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Explorer 355 and 532 - Spectra

1. 2 24 56 9 Y 0 20 5 M4 metric thread 2 places 2 56 All Measurements In lt 65 ES D inches lt 3 05 zi mm 77 5 hole 5 mm H7 3 74 2 places 95 2 13 54 A 1 00 25 4 Y y 6 47 The Explorer Laser System 164 9e ate OROLOLOLOLOLOLOLOR eS e ORORQSO OSOCO RO OR ORO ORO ORO OR OO OO OR OO COO ORO O OO ORORO OO OO OC COCHISE CC OO PON ORORO OFO CC BOQ 1 12 28 4 5 18 131 6 All Measurements In inches mm O POWER O EMISSION ERROR ANALOG IN Figure 3 9 Outline Drawing L Series Power Supply Explorer Actively Q Switched High Repetition Laser Systems 1 e9 S 0 6 697z gt lt GLO FPS10 I K X L OFS8L 00 92Z 956 p282 i L OFZ9L S 16L L Or6se 00 8 9 6697 660720201 Zl T 00 89L7 L OFOOL _ OFLE Soe eae 00 F297 Y Y Y Y Y yY Y L org zi T SEDED eo 20 00 7080 Lr Z S670 00 71680 di cee le Le EUSRE y c66 0 L Oz ze 00 616 2 8 T a r ol v00 600 F282 Ve cg P pP 4 001 gt g SHEE oO tt E gle E L OFZ S0L S SIE 00 Ferry Yn inst S p L OFZ ELL S 00 Gy v x p L OFY SZL N 00 7 6 v
2. liliis res D 9 Notes Report Form for Problems and Solutions Table of Contents List of Figures Figure 1 1 The Explorer Laser Head on left and L Series Power Supply 0005 1 1 Figure 2 1 These standard safety warning labels are appropriate for use as entry warning signs 2 2 Figure 2 2 Folded Metal Beam Target ilssseeeseeeeee rn 2 2 Figure 2 3 Laser Head Emission Indicator 0 0c eee eee 2 3 Figure 2 4 Power Supply Safety Devices 0 0 0c ccc eee 2 3 Figure 2 5 Explorer Radiation Control Drawing liliis 2 6 Figure 2 6 Explorer CE Warning Labels llisslselsee en 2 7 Figure 3 1 Optical Design of the Explorer Laser Head 0000 cece eee 3 2 Figure 3 2 Explorer System Control Hardware llssseeee tte ae 3 5 Figure 3 3 Variation of Energy and Pulse Width vs Current 00000 cece eee eee 3 6 Figure 3 4 Pulse Energy vs Pulse Repetition Rate 0 0 eee ee 3 7 Figure 3 5 Pulse Width vs Pulse Repetition Rate 0 0 0 ee 3 7 Figure 3 6 Burst Mode Timing Example 0 00 cece eh 3 8 Figure 3 7 The First Pulse Effect at High Repetition Rates 0 eee ee 3 9 Figure 3 8 Outline Drawing Explorer Laser Head 000 0c eects 3 12 Figure 3 9 Outline Drawing L Series Power Supply 060 000 c eee eee eee eee 3 13 Figure 3 10 Outline Drawing Heatsink Assembly 0000
3. CONT POW n4 xn2 na3 This command starts an automatic laser power adjustment The setting procedure lasts about 10 seconds lt n gt requested laser power in mW the range of n4 depends on the Explorer model See Table B 3 nz pulse repetition rate PRF for which the adjustment is to be executed the range of n depends on the Explorer model See Table B 3 na determines if the automatically adjusted parameters are stored or not after completion of the setting procedure N 0 The diode laser current is set to the adjusted current but is not saved to the internal EEPROM These settings can be manually stored by the user CONFIG PARSET STOR lt n gt This requires that the laser emission is disabled n 1 orn 2 The settings are automatically stored in user set 1 or 2 respectively Note 1 The command is rejected if the laser is not switched on During the adjustment procedure queries about the diode current pulse repetition frequency and temperatures are not valid Note 2 During the adjustment procedure the status may be queried using the command STAT COND OPER and checking if bit 13 Power setting is activated CONT POW 0 stops a launched adjustment procedure Examples gt CONT POW 50 20000 1 lt CR gt Request to set the laser power to 50 mW 20kHz After completion the found parameters diode current are stored in the user parameter set 1 lt lt CR gt lt LF gt g
4. Envelope FWHM Point z 6 10 GHz Gain Gain noon Frequency v Figure D 3 Frequency Distribution of Longitudinal Modes for a Sin gle Line The output of the laser is discontinuous within this line profile A standing wave propagates within the optical cavity and any frequency that satisfies the resonance condition _ mc or 3 will oscillate where v is the frequency c is the speed of light L is the opti cal cavity length and m is an integer Thus the output of a given line is a set of discrete frequencies called longitudinal modes that are spaced such that Av 2 4 A Brief Review of Laser Theory Nd as a Laser Medium In commercial laser designs the source of excitation energy for the gain medium is usually optical or electrical The output of one laser can be used to pump another e g a Ti sapphire laser can be pumped by an argon ion laser or a diode laser can be used to pump a solid state laser The Explorer uses the output from a diode laser to pump Nd ions doped in a yttrium crystalline matrix Nd YVO commonly known as Vanadate The properties of neodymium doped crystals such as Vanadate are the most widely studied of all solid state laser media The four level Nd ion scheme is shown in Figure D 4 The active medium is triply ionized neody mium which has principle absorption bands in the red and near infrared Following some non optical interactio
5. SUOOL lt P Jobi jeuj81u sojeniui 31 v5 jeusa xy g epojy Buneiedo JobBu 1 jeuj81uJ sejeniu AGG LS Ieujejx3l v epojy Buneaedo yo spor sing pue 19661 jeuj81u ejqeu3 Sd Buiunj 110g Bojeuy jeouoes ZL Nid NI 31vouexa g SI Nid NI Agals waxy V ith FPS and without Burst iggering w External Tri Figure 7 9 7 25 Explorer Actively Q Switched High Repetition Laser Systems ising ejou 40 peyesoueab si ou S ONAS LSHNA 1e58u 1 j euie1u uoee 10 paerua si ou S 0 ONAS LSHNG S SINNOO LSHNA 6L Nid LNO ouAs euJ91X3 z uondo 6I Nid LNO ou S jeu1 x4 Qinejap uondo indino Jose pes nd i Aeled Sdd lt s ureun Av130 sd4 AGGLS Ieujejxe AGGLS esau uey Aea suz e sw g uey 1e6uo Aga s Busa xe 4 40661 jeusa U queuing Jose epoiq A8lIS Jeu49ju Jo11uo2 jeuao1u SUOOL lt Il SUOOL lt x JebBu jeuj81u sejeniui 311 v5 JeuJo1x3 g epojy Buneiedo Jeb61 jeuJ81u sejeniur AGGLS Ieu481x3 v epojy Purjgaedo uo epojy 1sung pue 106611 jeuj91u ajqeuy Sd4 HOd Bojeuy Buiuirj je1euoes ZL Nid NI 31v5jeusex4 g SI Nid NI AS8GLIS Euje x3 WV th FPS and Burst iggering wi External Tri Figure 7 10 7 26 Chapter 8 Maintenance and Service Danger Spectra Physics Explorer lasers are Class IV High Power Lasers Laser Radiation whose beams are by definition safety and fi
6. This command sets the communication speed baud rate between the Explorer embedded controller and a customer control computer Range n 4800 9600 14400 19200 28800 38400 57600 bps bits per second Note At startup the system uses the last baud rate that was in effect Examples gt SYST COMM SER BAUD 14400 lt CR gt Set the actual baud rate to 14 400 bps gt SYST COMM SER BAUD CR lt 14400bps lt CR gt lt LF gt WDOG lt n gt WDOG This command sets the software watchdog alert time in seconds This is the watchdog timer for RS 232 communication between the embedded computer in the laser system and the host computer If the Explorer has not received commands from the customer s computer within the specified time the laser will turn off Unit sec Range lt n gt n 0 110 n 0 disables the watchdog timer default Values of 3 to 10 seconds would be typical Examples gt WDOG 10 lt CR gt Set the alert time to 10 seconds lt lt CR gt lt LF gt gt WDOG 0 lt CR gt Disable the software watchdog lt lt CR gt lt LF gt gt WDOG lt CR gt lt 0sec lt CR gt lt LF gt The software watchdog has been disabled B 34 Serial Commands and Queries Table B 3 Ranges for Automatic Energy Power Adjustment Voltage at Max Analog Min Pulse Pulse Min Pulse Max Pulse Min Average Max Average Port Pin 1 Repetition Repetition Energy Energy Power Power Output Freque
7. Before making any changes to the crystal temperatures record the starting values for the temperature settings in case you need to return to these settings When adjusting the temperatures for maximum UV pulse energy change the value for the THG crystal in maximum increments of 10 counts then allow the laser output to stabilize before making further changes Continue making small changes to the THG crystal temperature until a maximum pulse energy output has been achieved Next change the SHG crystal setting again by small increments wait ing for the laser output to stabilize before making further changes After a maximum value has been achieved by adjusting the SHG crys tal return to the THG adjustment Note the new starting values of the crystal temperature settings then see if making small changes to the THG temperature results in any further improvement in pulse energy If it improves make further small changes to the SHG crystal temper ature as well When optimum output has been achieved log the new temperatures along with the current and energy or power readings These settings can be saved in either User 1 or User 2 see Saving and Using Pre Set Operating Parameters on page 6 5 Return to the Main display to resume laser emission If the SHG and or THG temperature setpoints are changed too rapidly Explorer emission will be automatically switched off to prevent optical damage to the laser components The l
8. This command reads the measured THG temperature in counts Unit cnts Example gt READ SHG TEMP lt CR gt lt 2989cnts lt CR gt lt LF gt DIOD1 TEMP f DIOD1 TEMP This command sets the diode laser temperature in degrees C 18 0 lt f lt 38 0 Unit degC Examples gt DIOD1 TEMP 29 2 lt CR gt lt lt CR gt lt LF gt 2DIOD1 TEMP CR 29 2degC lt CR gt lt LF gt READ DIOD1 TEMP This command reads the actual laser diode temperature in degrees C Unit degC Example gt READ DIOD1 TEMP lt CR gt 29 2degC lt CR gt lt LF gt Q Switch Repetition Rate QSW PRF lt n gt QSW PRF This command sets the Q switch repetition frequency in Hertz 0 lt n lt maximum pulse repetition frequency i e the value returned by QSW PRF MAX n 0 is disables internal pulse triggering and allows external triggering Unit Hz Table B 3 lists the PRF range for the Explorer models Examples gt QSW PRF 50000 lt CR gt Set the pulse frequency to 50000 Hz lt lt CR gt lt LF gt gt QSW PRF lt CR gt 50000Hz CR LF gt QSW PRF 0 lt CR gt Set the system to external triggering mode lt lt CR gt lt LF gt B 6 Serial Commands and Queries QSW PRF MAX This command reads the maximum pulse repetition frequency Unit Hz Table B 3 lists the maximum pulse repetition frequencies for the Explorer models Examples gt Q
9. 20 to 60 C Maximum relative humidity lt 90 non condensing This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment This equip ment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instruction manual may cause harmful interference to radio communications Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense Modifications to the laser system not expressly approved by Spectra Physics could void your right to operate the equipment Table of Contents Preface wi Acahrieet isa Rari eee ditched ad Phas eR edenda iE eee iii CE Environmental Specifications llle V CE Electrical Equipment Requirements 0 000 cee tees V Environmental Specifications 0 0 0c err V FCC Reg lations 2 irme acm RE RU RT EE BE EC ee d Reo PEU ae V Warning Conventions c uuueo reum xxr eee eee ee xiii Standard Units cis issi eroki ausum ead m kw ee eee dae XV Abbreviations 6 cide t ceed ee Pk eee RR eek ewe EUR RR RR d xvii Unpacking and Inspection 0 0 eee eee xix Unpacking te Laser ot sees eed Phd Re
10. 4 factory settings 2 B 20 Serial Commands and Queries Example gt CONFIG PARSET LOAD 1 lt CR gt lt lt CR gt lt LF gt CONFIG PARSET STOR lt n gt This command stores actual parameters as parameter set lt n gt refer to Table B 7 User Parameters Range lt n gt 1 2 n 1 user parameter set 1 n 2 user parameter set 2 Example gt CONFIG PARSET STOR 1 lt CR gt lt lt CR gt lt LF gt CONT AUTOON lt n gt CONT AUTOON This command sets the Auto on feature of the laser system n 1 enables Auto on mode The ON command starts laser emission without a keyswitch reset i e turning the key OFF and ON n 0 disables Auto on mode After the system is booted or after a critical error a keyswitch reset i e turning the key OFF and ON is necessary to start laser emission with the ON command CONT PENER lt n4 gt lt n2 gt lt n3 gt This command starts an automatic pulse energy adjustment The setting procedure lasts about 10 seconds lt ni gt requested pulse energy in uJ The range of n4 depends on the Explorer model See Table B 3 lt n gt pulse repetition rate PRF for which the adjustment is to be executed see Table B 3 for the valid PRF range na determines if the automatically adjusted parameters are stored or not after completion of the setting procedure n 0 The diode laser current is set to the adjusted current but not saved
11. Host Analog TTL N Power Supply Rear Panel System Control LASERHEAD 2 o PS L08 Head2 Laser Head Rear Panel PS L08 Head1 Auxiliary Cooling Fan Figure 5 3 System Interconnect Drawing Explorer Actively Q Switched High Repetition Laser Systems Note g Laser Alignment 5 4 Attach the Laser Head 1 control cable PS L08 Head1 between the LASERHEAD 1 connector on the power supply and the Laser Head Cable 1 connector on the laser head Attach the Laser Head 2 control cable PS L08 Head2 between the LASERHEAD 2 connector on the power supply and the Laser Head Cable 2 connector on the laser head Attach a 2 wire or 4 wire cord suitable for 4 A between the DC IN connector on the power supply and the DC power source We recom mended using 2 pins of the 24 Vdc line and 2 pins of the return line to lighten the current load Refer to Figure 4 6 on page 4 5 for pin descriptions Make sure that the required voltage of 22 26 Vdc at 4 A is available at the DC IN connector Furthermore the off load voltage of the DC source cannot exceed 30 Volts Recall that pins 6 and 7 form a relay that can be used to turn on an emission indicator when the laser is on This relay is rated for a maxi mum 48 Vdc at 1 A It is recommended that the control circuitry provided for a user sup plied fan be used to maintain proper heatsink temperature Refer to the description of the FAN connector under Rear P
12. e Q switch trigger e pulse gating e synchronous output trigger signals To use this interface communication must first be established with the Explorer using either the L Win software or through serial commands from a host system Analog control is enabled by setting the Control mode switch to analog on the L Win Main display or by executing the serial com mand MODE RMT 0 A default state description of the pins of the ANALOG IN interface is given in Table 7 2 Configuring Analog Control on page 7 8 describes how the functions of some of the pins can be set to a different polarity Table 7 2 is followed by examples of how to use the ANALOG IN interface to perform some of the more common laser operations 7 15 Explorer Actively Q Switched High Repetition Laser Systems The configuration and status of the pins of the ANALOG IN interface are set and queried using serial commands This is accomplished by modifying or querying two bytes that encode some of the functions of the ANALOG IN connector pins The Analog Port Polarity Configuration byte and the Ana log Port Status byte Refer to Configuring Analog Control on page 7 8 for more information about using these bytes Tables of these two bytes are provided at the end of Appendix B Table 7 2 ANALOG IN Pin Description Pin Type Description Function 1 Output Analog Pulse Energy Pulse Energy monitor Average Energy monitor Output
13. 0 2 F 0 I li 0 10 20 30 40 Ambient Temperature C Figure 5 1 Laser Head Heatsink Thermal Impedance Requirement Spectra Physics offers an optional heatsink with an auxiliary fan that can be attached to the laser head and controlled through the L Series power 5 1 Explorer Actively Q Switched High Repetition Laser Systems Alignment Pin Laser Head Cables supply Refer to the fan connector description under Rear Panel Connec tions on page 4 6 for details A temperature sensor located inside the laser head continuously measures the laser head temperature and provides feed back for controlling fan RPM When active the servo loop maintains a constant laser head temperature at a value set using serial commands The default laser head temperature is 35 C The lower the environmental temperature the lower the fan speed will be A temperature setting below ambient will result in the fan operat ing at a constant maximum speed As soon as the head temperature exceeds 40 C typical Error Code 39 Warning Overtemp Laser Head is issued but the laser will continue to operate normally However exceeding 45 C will cause an emergency shut off whereby the laser is immediately placed into Sleep mode Sleep mode can be exited by restarting the laser after the laser head temperature has dropped below 40 C typical again Refer to System Temperature Management on page 7 10 for information on
14. 1 user parameter set 1 n 2 user parameter set 2 n 3 factory settings 1 n 4 factory settings 2 Example gt CONFIG PARSET ACT lt CR gt 1 CR LF Serial Commands and Queries CONFIG PARSET BOOT lt n gt CONFIG PARSET BOOT This command designates the parameter set indicated by number to be loaded at next startup refer to Table B 7 User Parameters Range lt n gt 1 4 n 1 user parameter set 1 n 2 user parameter set 2 n 3 factory settings 1 n 4 factory settings 2 Examples gt CONFIG PARSET BOOT 1 lt CR gt lt lt CR gt lt LF gt gt CONFIG PARSET BOOT lt CR gt lt 1 lt CR gt lt LF gt Status and Error Reporting READ FAULT This command reads the fault code refer to Table C 3 0 means there are no errors Example gt READ FAULT lt CR gt 12 CR LF The user interlock has been activated READ FAULT LIST This command reads a string of up to 16 status codes which are currently active refer to Table C 3 Entries are separated by blanks 0 means there are no errors Example gt READ FAULT LIST lt CR gt 12 23 24 25 lt CR gt lt LF gt READ FAULT HIST This command reads the history buffer which consists of up to 16 status codes activated after the most recent startup refer to Table C 3 Entries are separated by blanks Example gt READ FAULT HIST lt CR gt lt 0 12 24 13 12 23
15. 14 15 17 18 19 21 25 N A Do not connect 26 Reference EARTH PS chassis ground Low impedance DC path to supply return power interface See Table B 3 for calculating the pulse energy or average power The default polarity is falling edge high low but it can be changed to rising edge low high using the serial command CONFIG APORT POLAR n 3 Internal pull up 10 9 kQ to 5 V default or internal pull down 8 2 kQ to GND depending on user commanded polarity configuration CONFIG APORT POLAR lt n gt TTL levels apply The default active level is low but it can be changed to active high using the serial command CONFIG APORT POLAR n Explorer Actively Q Switched High Repetition Laser Systems Basic Analog Operation Turning the Laser On and Off 7 18 Setting the laser emission control to Analog Interface MODE RMT 0 through the RS 232 interface allows the Explorer laser to be turned on and off using a single analog control signal on pin 10 active low The laser uses either the last commanded diode current set point or the default preset values after turn on as the operating parameter The output of pin 11 is pulled low when the laser has reached a stable oper ating condition i e the TECs for the nonlinear crystals and the diode laser have reached the default temperature set points This signals that the laser is ready for use To turn the laser on using pin 10 pin 11 must be low
16. lt LF gt gt POW REFVOLT CNTS lt CR gt lt 456cnts lt CR gt lt LF gt CONT POW lt n gt lt n2 gt lt n3 gt This command starts an automatic laser power adjustment The setting procedure lasts about 10 seconds lt n gt requested laser power in mW the range of n4 depends on the Explorer model See Table B 3 lt n gt pulse repetition rate PRF for which the adjustment is to be executed the range of n depends on the Explorer model See Table B 3 lt n gt determines if the automatically adjusted parameters are stored or not after completion of the setting procedure n 0 The diode laser current is set to the adjusted current but is not saved to the internal EEPROM These settings can be manually stored by the user CONFIG PARSET STOR lt n gt This requires that the laser emission is disabled n 1 or n 2 The settings are automatically stored in user set 1 or 2 respectively Note 1 The command is rejected if the laser is not switched on During the adjustment procedure queries about the diode current pulse repetition frequency and temperatures are not valid Note 2 During the adjustment procedure the status may be queried using the command STAT COND OPER and checking if bit 13 Power setting is activated CONT POW 0 stops a launched adjustment procedure Examples gt CONT POW 50 20000 1 lt CR gt Request to set the laser power to 50 mW 20kHz After completion the found parameters di
17. mation concerning the proper disposal of this product Explorer Actively Q Switched High Repetition Laser Systems CE Declaration of Conformity 2 10 We Spectra Physics 3635 Peterson Way Santa Clara CA 95054 United States of America declare under sole responsibility that the Laser System Model Explorer 355 Explorer 532 manufactured after September 18 2008 meets the intent of EMC Directive 2004 108 EC for electromagnetic compatibility and LVD Directive 2006 95 EC for low voltage directives Compliance was dem onstrated to the following specifications as listed in the official Journal of the European Communities EMC Directive 2004 108 EC EN 55011 1998 A1 A2 industrial scientific and medical ISM radio fre quency equipment radio disturbance characteristics conducted and radiated emissions EN 61000 4 2 1995 A1 A2 Electrostatic discharge immunity test EN 61000 4 3 2002 A1 Testing and measurement techniques radiated radio frequency electromagnetic field EN 61000 4 4 1995 A1 A2 Testing and measurement techniques elec trical fast transient burst immunity test EN 61000 4 5 1995 A1 Testing and measurement techniques surge immunity test EN 61000 4 6 1996 A1 Testing and measurement techniques immunity to conducted disturbances induced by radio frequency fields Low Voltage Directive 2006 95 EC EN60825 1 2007 Equipment classification requirements and users guide EN60950 1
18. set point The maximum diode current is set at the factory A signal voltage of 4 095 V corresponds to 100 of the maximum diode current which is returned by DIOD1 MAXC To activate analog diode laser control pin 18 on the ANALOG IN port must be pulled low prior to enabling laser emission on pin 10 During emission the mode of operation cannot be changed Figure 7 3 shows an example of a circuit that can be used to supply the trigger signal External Q Switch Triggering Note Internal triggering is the default setting for the Explorer laser To switch to external triggering send the serial command QSW PRF 0 which enables pin 21 of the ANALOG IN port Once this command has been sent no emis sion will occur until a TTL signal is provided on pin 21 to trigger the laser The external trigger signal applied to pin 21 should be a TTL level falling edge input default setting see Appendix B and Table B 4 from single shot to 60 kHz or 20 to 150 kHz depending on the Explorer model Figure 7 3 shows an example of a circuit that can be used to supply the trigger signal Explorer lasers are designed for pulse repetition rates above 20 KHz Lower frequencies can result in unstable laser operation To avoid insta bility decrease the pump diode current or increase the pulse repetition rate Setting the Laser to Standby To place the Explorer in Standby mode force pin 15 low default setting see Appendix B and Table B 4 Again s
19. ture 34 Software watchdog trig gered Hardware watchdog trig gered User interlock activated 12 Keyswitch interlock acti vated 13 Analog mode EXT_DIODE_ON signal changed Diode temperature not stabilized signifi cant offset from set temperature or tem perature controller not working properly Diode cable not connected or connection faulty Diode current can not be adjusted by hardware control loop SHG crystal temperature not stabilized significant offset from set temperature or temperature controller not working properly THG crystal temperature not stabilized significant offset from set temperature or temperature controller not working properly Either the main PCB temperature or the digital controller PCB temperature in the power supply housing exceeded the safety shutdown temperature limit Either the heatsink temperature or the controller PCB temperature in the laser head exceeded the safety shutdown temperature limit The software watchdog is activated No serial command was sent to the Explorer within the adjusted alert time Unexpected behavior of the control soft ware e g infinite loop The user interlock was triggered by an external wiring loop or by removing the analog plug The keyswitch was turned off The level of the EXT_DIODE_ON signal changed from LOW to HIGH or from HIGH to LOW depending on the analog port polarity configuration Error LED is lit F
20. 2 Operating Status and Error Bits Continued Bit Active Description Condition Action Required System Condition ANALOG PORT Register Query STAT COND SYST APORT 0 MISSING EXT DIODE ON The laser is in Analog mode Apply an appropriate signal to To start laser emission a sig pin 10 nal must be applied to pin 10 of the ANALOG port System Condition DIODE Register Query STAT COND SYST DIOD1 0 ERROR CABLE The laser head cable is not Check the cable connection correctly connected between the power supply and laser head If the problem persist contact Spectra Physics service 1 ERROR CURRENT The diode current driver con Contact Spectra Physics service trol loop is at its limit System Condition COMPATIBILITY Register Query STAT COND SYST COMPAT O0 HARDWARE MISMATCH The PCB versions of power Contact Spectra Physics service supply and laser head do not match 1 N A 2 LASERHEAD SOFTWARE MIS The power supply software Contact Spectra Physics service MATCH does not match the laser head software version 3 TEMPCONTROLLER A SOFT The power supply software Contact Spectra Physics service WARE MISMATCH does not match the software version of the temperature controller A 4 TEMPCONTROLLER A SOFT The power supply software Contact Spectra Physics service WARE MISMATCH does not match the software version of the temperature controller B System Condition SOFTWARE EXCEPTION Register Query STAT CO
21. 2006 Safety of Information Technology Equipment EN61010 1 2001 Corr 1 Corr 2 General Requirements Safety require ments for electrical equipment for measurement I the undersigned hereby declare that the equipment specified above conforms to the above Directives and Standards Daek Dave Allen Vice President and General Manager Lasers Division of Newport Corporation September 18 2008 Laser Safety Sources for Additional Information Laser Safety Standards Safe Use of Lasers Z136 1 American National Standards Institute ANSI 25 West 43 Street 4 Floor New York NY 10036 Tel 212 642 4900 Occupational Safety and Health Administration Osha Standard 01 05 001 pub8 1 7 U S Department of Labor 200 Constitution Avenue N W Room N3647 Washington DC 20210 Tel 202 693 1999 Web site http www osha gov A Guide for Control of Laser Hazards 4th Edition Publication 0165 American Conference of Governmental and Industrial Hygienists ACGIH 1330 Kemper Meadow Drive Cincinnati OH 45240 Tel 513 742 2020 Web site http www acgih org home htm Laser Institute of America 13501 Ingenuity Drive Suite 128 Orlando FL 32826 Tel 800 345 2737 Web site http www laserinstitute org International Electrotechnical Commission Journal of the European Communities IEC 60825 1 Safety of Laser Products Part 1 Equipment classification requirements and user s guide Tel 41 22 919 0211
22. 21uJ CR LF READ PENER HIST This command reads the energy values of the first 50 pulses after switching on or after the last read out of the pulse history The values are given in ADC counts 0 1023 and are separated by blanks Pulse energy in uJ may be calculated by multiplying by the calibration factor output of query PENER CALF Examples gt READ PENER HIST lt CR gt 455 772 781 776 776 778 773 lt CR gt lt LF gt gt READ PENER HIST lt CR gt lt 0 lt CR gt lt LF gt No pulses have been emitted yet PENER CALF This command reads the calibration factor which is used to convert the pulse energy ADC counts 0 1023 to the displayed microjoule values The calibration factor is set at the factory Unit uJ cnt Example gt PENER CALF lt CR gt 0 5234yJ cnt lt CR gt lt LF gt PENER REFVOLT CNTS lt n gt PENER REFVOLT CNTS This command modifies the reference voltage of the pulse energy ADC It may be used to re calibrate the displayed pulse energy to match the values read at the user s energy meter Higher reference voltage counts result in lower pulse energy values Range n 200 1023 Unit cnts Examples gt PENER REFVOLT CNTS 456 lt CR gt lt lt CR gt lt LF gt gt PENER REFVOLT CNTS lt CR gt lt 456cnts lt CR gt lt LF gt B 9 Explorer Actively Q Switched High Repetition Laser Systems CONT PENER lt n gt lt
23. 6 1 lt CR gt lt LF gt READ PCUR lt n gt This command reads the actual diode laser current in of the diode current limit Unit 961 Example READ PCUR CR 67 6 1 lt CR gt lt LF gt B 4 Serial Commands and Queries DIOD1 STANDBYC This command reads the diode laser standby current in Amps Example gt DIOD1 STANDBYC lt CR gt 0 5A1 CR LF DIOD1 MAXC This command returns the diode laser current limit in Amps The diode current limit is set at the factory Example gt DIOD1 MAXC lt CR gt 5 5A1 CR LF Diode and Crystal Temperature Control CONT SHG TEMP n CONT SHG TEMP This command sets the SHG temperature in counts 100 lt n x 4000 Unit cnts Examples gt CONT SHG TEMP 1650 lt CR gt lt lt CR gt lt LF gt gt CONT SHG TEMP lt CR gt 1650cnts lt CR gt lt LF gt READ SHG TEMP This command reads the measured SHG temperature in counts Unit cnts Example gt READ SHG TEMP lt CR gt lt 1649cnts lt CR gt lt LF gt CONT THG TEMP lt n gt CONT THG TEMP This command sets the THG temperature in counts 100 x n x 4000 Unit cnts Examples gt CONT THG TEMP 2988 lt CR gt lt lt CR gt lt LF gt gt CONT SHG TEMP lt CR gt 2988cnts lt CR gt lt LF gt B 5 Explorer Actively Q Switched High Repetition Laser Systems READ THG TEMP
24. 8 8 8 8 81 CJ Y EE SS 81 9 11 TE E E E E S S SS ISIS SS SAAI SISSIES TISSI SSS 8 8 8 S N DIOL S ULV S Sz VL EL Q f ELE LS LVL EL ELV XS 0 System Identification IDN read system identification string read complete identification string including diode serial number and IDNC PWM temp controller SW versions Serial Communication Baudrate set baudrate for user communication SYST COMM SER BAUD lt n gt via RS232 be ie de eelael ie X X X read baudrate for user communication SYSTCOMMSSERBAUD va 85232 eT JE Hil x x Remote Computer or Analog Interface Mode place system in remote computer or MODE RMT n analog interface mode ERHEHEERFEBEF X X X MODE RMT read actual remote mode setting LI Tt tt ft IX X X Diode Current DIOD1 CURR lt f gt Set diode current X X X X X return the last commanded diode DIOD1 CURR current X X X X X READ DIOD1 CURR return the actual diode current X Xx XIX set diode current to f of PCUR lt f gt maximum current LESSE ETE Eb EE E X X X X return the last commanded diode PCUR current in of the maximum current PA Oe X X return the actual diode current in of READ PCUR the maximum current ca led Meal Et ela sl X X KIA return adjusted diode maximum DIOD1 MAX current PAE Wee Wiese dee X X X DIOD1 STANDBYC return adjusted diode standby current ASI Meee Meals Al X XXIX Pulse Repetition Frequency set pulse repetition frequency in Hz QSW PRF n O external trigger mode x x
25. 8 b sddea od ed Db Bere DP nite er eb acit ere ik s ood ds 5 6 TUtb Off 2 5 bot oet mue Dated oer e bar Deki Qe cege eet al aedes ios Shien i de aed 5 7 Chapter 6 Operating Using the L Win Software seleess 6 1 Basic Operating Control lsslelseeeeleele rre 6 2 Turningthe Easer On and Off socis e we eves od er tex dux uda ees 6 2 Adjusting the Pulse Energy and Average Power 000 c eee eee nee 6 3 Changing the Pulse Repetition Rate 0 0 tee 6 3 Setting the Laser to Standby 000 c cette 6 3 Sleep MOde i cute Sea eR eR dapes rte ell a pte m EY ee 6 4 Saving and Using Pre Set Operating Parameters 00 00 cece eae 6 5 Setting the Auto On Mode ssussselelsellle rre 6 5 Monitoring and Adjusting Performance 0 0 ccc eee 6 6 viii Table of Contents System Settings seus sepu Re eae led bee fy Aes ded te oda Heed bao ede eed ede 6 8 Calibrating the Pulse Energy Monitor Readings or Average Power Monitor Readings 6 8 Tracking Operating Hours er pexPeiseRhrexX eb aed ered ales QUEE Puls YE d 6 9 selecting Analog Control idu me a tie Pe HERR Me CREE e ee a eg 6 10 Changing the Q Switch Trigger Source 0 0 00 ett 6 10 Component Temperature Adjustment 0 00 ccc ren 6 11 Setting the Diode Pump Laser Temperature 0 0000 cece eee 6 11 Setting the SHG and THG Temperatures 0000 cece eee 6 13 Advanced Contro
26. Calibration Settings pulse energy calibration Factor GUI only Jj 1 00 Auto on Control J Start Emission without key switch reset Auto On Select Start up Parameter Set Activate Preset Store Settings in Boot with Preset Power Supply Preset Select Parameter Set to Activate Save Present Parameter Set Useri x Useri V Useri V Figure 6 3 Settings Tab Selecting Operating Parameters Pre sets can only be stored or activated when laser emission is off Clicking on the Settings tab in the Main display causes the Settings display to be shown Figure 6 3 This display is used to enable laser operation using a stored set of parameters either saved by the user or pre set at the factory To save the current operating parameters select either User 1 or User 2 in the Store Preset section of the display then click on OK to save To use a saved set of operating parameters select either User 1 or User 2 in the Activate Preset section of the display Factory 1 and Factory 2 are also available These factory parameter sets cannot be changed by the user Click on OK to operate the laser using the selected set of parameters Select a parameter set from the Boot with Preset section and click on OK to designate the parameter set to be activated the next time the system is booted Save these settings to make this change permanent Setting the Auto On Mode The Settings display may also be used to activate the Au
27. EXT DIODE ON W EC30 EXTERNAL DIODECURRENT SYNC OVER BURST STATus CONDition SYSTem PowerSUPPLY SYNC AFTER Q5W ERROR PS PCB OVERTEMP El EC33 38 ERROR DIGCONT PCB OVERTEMP EMI EC33 38 STATus CONDition SYSTem COMPATIibility HARDWARE MISMATCH TE EC35 POWERSUPPLY SOFTWARE MISMATCH W EC36 LASERHEAD SOFTWARE MISMATCH W EC36 TEMPCONTROLLER A SOFTWARE MISMATCH TE EC36 TEMPCONTROLLER B SOFTWARE MISMATCH T EC36 STATus CONDition SYSTem SOFTware EXC_ Figure A 12 Status and Error Display L Win GUI Reference STATus CONDition CoMmanD UNKNOWN COMMAND w COMMAND NOT ALLOWED Sal INVALID PARAMETER Sli COMMAND FAILED d STATus CONDition SYSTem PARAMETERSET LASERHEAD EN TEMPERATURE CONTROLLER STB LASERDIODE d ANALOG INTERFACE LASER EMISSIOM POWERSUPPLY reserved CMD_ERROR HW SW MISMATCH alll Bit 14 SYSTEM_ERROR SOFTWARE EXCEPTION WE Bit 15 reserved STANDARD_EVENT reserved STATus CONDition E ENts ee USER INTERLOCK W EC12 KEY INTERLOCK EE EC13 KEYLOCK WEN EC48 SYSTEM BOOT SOFTWARE WATCHDOG HARDWARE WATCHDOG STATus CONDition OPERational STANDBY ACTIVE TH BURST BUSY READY MODE SLEEP MODE CW MODE GATE Laser Serial Port ASRLI gt Loop Time s Jj 3 00 RANDOM PLILSING MODE j EXTERNAL_TRIGGER FIRST_PULSE_SUPPRESSION LASER WARMUP PULSE ENERGY SETTING Access Level USER The Status and Error display shows all the condition flags in a tree struc ture wi
28. Example gt STAT COND SYST DIOD1 lt CR gt lt 2 lt CR gt lt LF gt Diode laser current control error Serial Commands and Queries STAT COND SYST TCONT This command reads temperature controller status refer to Table C 2 Example gt STAT COND SYST TCONT lt CR gt 32 lt CR gt lt LF gt PWM controller for diode laser temperature failed STAT COND SYST APORT This command reads analog interface status refer to Table C 2 Example gt STAT COND SYST APORT lt CR gt lt 1 lt CR gt lt LF gt Missing EXTERNAL_DIODE_ON signal STAT COND EVEN This command reads system events status refer to Table C 2 Example gt STAT COND EVEN lt CR gt lt 4 lt CR gt lt LF gt Keyswitch is in OFF position STAT COND OPER This command reads system operational status refer to Table C 2 Example gt STAT COND OPER lt CR gt lt 8 lt CR gt lt LF gt System is in SLEEP mode Power Saving Modes MODE SLEEP lt n gt MODE SLEEP This command activates deactivates Sleep mode In Sleep mode the Q switch and the TECs for controlling the temperatures of the harmonic crystals and diode laser are turned off Range lt n gt n 1 Sleep mode on n 0 Sleep mode off Note in Sleep mode all commands besides status queries are rejected Examples gt MODE SLEEP 1 lt CR gt Activate Sleep mode lt lt CR gt lt LF gt gt MODE
29. Fax 41 22 919 0300 Web site http www iec ch Cenelec 35 Rue de Stassartstraat B 1050 Brussels Belgium Tel 32 2 519 68 71 Web site http www cenelec eu Document Center Inc 111 Industrial Road Suite 9 Belmont CA 94002 Tel 650 591 7600 Web site http www document center com Explorer Actively Q Switched High Repetition Laser Systems Equipment and Training 2 12 Laser Safety Guide Laser Institute of America 13501 Ingenuity Drive Suite 128 Orlando FL 32826 Tel 800 34LASER Web site http www laserinstitute org Laser Focus World Buyer s Guide Laser Focus World Pennwell Publishing 98 Spit Rock Road Nashua NH 03062 Tel 603 891 0123 Web site http pennwell 365media com laser focus world search html Photonics Spectra Buyer s Guide Photonics Spectra Laurin Publications Berkshire Common PO Box 4949 Pittsfield MA 01202 4949 Tel 413 499 0514 Web site http www photonics com Chapter 3 Note 6 The Explorer Laser System An Explorer laser system consists of an Explorer laser head an L Series power supply and control software The following sections briefly describe the design of the laser head and power supply Controls and connections are described in Chapter 4 and the methods of operating the laser are described in Chapters 6 and 7 Appendix D provides an introduction to the physical principles that underlie the design of the Explorer laser T
30. Low active Polarity active level can be changed using the serial command CONFIG APORT POLAR n Examples To set the polarity of the External trigger pin to rising edge while keeping all other polarities to defaults the command to change the polarity is CONFIG APORT POLAR 4 bit 2 gt 2 To set both the polarity of the External trigger pin and of the External Gate pin to rising edge while keeping all other polarities to defaults the command to change the polarity is CONFIG APORT POLAR 12 bit 2 bit 3 gt 2 2 4 8 12 Table B 6 Analog Port Signal Status Bits Bit Description Bit is high O External diode current source if pin 18 ILD SOURCE is active 1 reserved N A 2 External trigger if pin 21 EXT TRIG is active 3 External gate if pin 17 EXT GATE is active 4 reserved N A 5 External standby if pin 15 STANDBY is active 6 External diode on if pin 10 EXT_DIODE_ON is active 7 reserved N A Active low or high depends on ANALOG port polarity configuration B 37 Explorer Actively Q Switched High Repetition Laser Systems Table B 7 User Parameters The parameters in this table comprise a user parameter set Two different sets can be defined and stored as User Set 1 and User Set 2 Parameter Description SHG temperature THG temperature Diode temperature Diode current Pulse repetition frequency Operating mode for fan heat sink Set tempe
31. Noise Display A 16 SEET Statistics vi E j xj FS Laser SerialPort komi v Statistics Statistics calc every X measurements Jo max value 14950 Pulses 63 48 61 25 mean min value 58 72 61 23 ms value max min mean 6 in 1 04 sigma in 11 30 9 Online Histogram Histo Intervals 20 2200 2000 7 Or 58 000 59 000 60 000 61 000 62 000 63 000 64 000 Energy p Figure A 16 Pulse Noise Display The Pulse Noise display can be used to monitor performance in terms of pulse to pulse stability by monitoring the pulse energies and displaying their distribution in a histogram with other statistical data Note this dis play only applies to EXPL xxx yyy E lasers Used concurrently with this display the L Win Main display can be used to improve performance by adjusting operational parameters such as diode laser current and repetition rate Laser Serial Port field shows the active serial port for communica tion with the system Clear button clears all data fields QUIT button closes the display Pulses field displays the number of pulses sampled mean field displays the calculated mean energy of sampled pulses rms value field displays the root mean square value of the sam pled values excluding that of the first pulse L Win GUI Reference sigma in field displays the value of the standard deviation of all pulses excluding the first Statistic
32. Power Energy Measurement Calibration Figure A 10 Tools Menu Pulse Energy The Tools pull down menu provides the following functions Terminal opens a terminal emulation program window see Termi nal Display on page A 9 that can be used to communicate with the laser system via serial commands Refer to Appendix B for a complete list of serial commands queries and responses Terminal Display L Win GUI Reference Status Bits Viewer provides tools for troubleshooting the system by displaying various status and error bits of the system components Refer to Status Bits Viewer on page A 11 Pulse Noise Measurement displays performance statistics such as pulse to pulse stability Refer to Monitoring and Adjusting Perfor mance on page 6 6 FPS Burst Setup allows adjustment and performance monitoring of the FPS and Burst mode settings Refer to FPS and Burst Control Display on page A 14 and Advanced Control of the Pulsed Output on page 6 14 Dump System Settings stores a snapshot of all relevant settings of the Explorer system in an external file Just follow the on screen instructions This information can be used for troubleshooting the sys tem by Spectra Physics service engineers Set Output Power Energy opens a new window where the output pulse power high rep rate systems or average energy low rep rate systems can be set Refer to Set Output Power Energy on page A 12 M
33. Power Scale 0 4V Tolerance 5 10 Maximum load 2 kQ 2 Input Analog EXT External diode current control Active if ILD SOURCE Pin 18 is pulled low high Scale 0 4V 096 1009 6 of diode current limit 3 N A Do not connect 4 N A Do not connect 5 N A Do not connect 6 N A Do not connect 7 Output Power USR ILK 12 V line with 470 Q source impedance Must be shorted to Pin 8 by a floating contact to complete the interlock return cir cuit 8 Input Power USR ILK RTN Must be shorted to Pin 7 by a floating contact to complete the interlock return circuit Typical current is 10 mA The floating contact resistance must be 100 O see Note 9 Output Digital EMISSION L Open Collector OC line pulls low when laser emission is active TTL level see Figure 7 4 10 Input Digital EXT DIODE ON Internal pull up Pull and keep low high to trigger the diode laser on Release high low to shut laser emission off Disabled in remote computer mode 11 Output Digital READY Open Collector OC line pulls low when the laser is opera tional TTL level see Figure 7 4 12 N A Do not connect 13 Output Digital ILK FAULT Open Collector OC line pulls low when the laser interlock is open TTL level see Figure 7 4 14 Output Digital PULSE Pulls low high when an optical pulse has been detected MONITOR May not appear at 596 maximum specified pulse energy OPTO SYNC Source HCT gate 5 V 50 Q series resis
34. Q Switched High Repetition Laser Systems Basic Operating Methods 000 c eee 7 22 Method A xu eser enes Rie n d bur ePUPPex Edu eI I Ee dU ahd lube ese 7 23 Method B ssi nscpensturpu eaten eka ad shale ein dee eae ied ds eas Pee ee ana 7 23 Advanced Control of the Pulsed Output 20 0000 0c ete ee 7 24 GAtING s ote eine E ek Her EE eis cathe ewlauede e ots few oie E bus vis 7 24 Burst O tput coc erede LR EE AE RRRAAI PRG Iu OR Sia ed onmuhea dd E 7 24 Chapter 8 Maintenance and Service 0 00 cece eee eee eee 8 1 Troubleshooting ille eee a ed eee dk bd added MOD RR ERU pe ie ded we 8 1 Corrective Procedures 0 0 c cette ae 8 3 The L Series Power Supply ssussessleselsee rn 8 3 Removing and Cleaning the Output Window 0000 ae 8 3 Service Training Programs 0 0 eae 8 7 Replacement Parts reple ata Dy en kee Pee e rx xe RID RA RE UR ba ae evens 8 7 Customer Service case ien keia aaia aa i a a nnn ete eee eas 8 8 Warratity zo dote cod a Mn acc a eus otk me rcp bar EA A EER TA 8 8 Mule 8 9 Return of the Instrument for Repair iiilseeeeeee nh 8 9 Service Centers a2 ET 8 10 Appendix A L Win GUI Reference 000c cece eee eee eee eee A 1 E Win Main Display oues paw Gwe Foe eee he bg ER RE pee ce Paar qe bani A 1 Status Panel 4 notre ot tere Ea odis Ex as PAS epa Miche cuu dice tare ara A 2 Gontrol Sectlon vid iio lr dem eens aie l
35. READ FAULT LIST This command reads a string of up to 16 status codes which are currently active Entries are separated by blanks refer to Table C 3 0 means there are no errors Example READ FAULT LIST CR 12 23 24 25 lt CR gt lt LF gt READ HEAD BAS TEMP This command reads the temperature of the laser head base plate in degrees C Unit degC Example gt READ HEAD BAS TEMP CR lt 34 5degC lt CR gt lt LF gt READ HEAD HOUR This command reads the laser head hours Laser head hours are incremented every 6 minutes 0 1 hour that power is supplied to the laser head Unit HrsHd Example gt READ HEAD HOUR lt CR gt lt 456 2HrsHd lt CR gt lt LF gt The laser head has been supplied with power for 456 2 hours READ PCUR This command reads the actual diode laser current in of the diode current limit Unit 961 Example gt READ PCUR lt CR gt lt 67 6 1 lt CR gt lt LF gt B 30 Serial Commands and Queries READ PENER This command reads the actual pulse energy in pJ Unit uJ Example READ PENER CR 21uJ lt CR gt lt LF gt READ PENER HIST This command reads the energy values of the first 50 pulses after switching on or after the last read out of the pulse history The values are given in ADC counts 0 1023 and are separated by blanks Pulse energy in uJ may be calculated by multiplying by the
36. SLEEP lt CR gt 1 CR LF Explorer Actively Q Switched High Repetition Laser Systems Laser Head Temperature Control HEAD BAS TEMP MAX This indicates the warning level of the laser head base plate temperature in degrees C An over temperature warning will be issued if the temperature rises above this maximum and a safety shutdown occurs if the temperature rises 5 C above the warning level Example gt HEAD BAS TEMP MAX CR lt 40degC lt CR gt lt LF gt READ HEAD BAS TEMP This command reads the temperature of the laser head base plate in degrees C Unit degC Example gt READ HEAD BAS TEMP CR lt 34 5degC lt CR gt lt LF gt HEAD FANCONT MODE lt n gt HEAD FANCONT MODE This command sets the operation mode of a connected fan either to Control mode where the base plate temperature is regulated to the adjusted set point refer to command HEAD FANCONT TEMP lt f gt or to Drive mode which provides a constant but adjustable voltage Range n n 1 control mode n 0 drive mode default Examples gt HEAD FANCONT MODE 1 lt CR gt lt lt CR gt lt LF gt gt HEAD FANCONT MODE lt CR gt 1 lt CR gt lt LF gt HEAD FANCONT TEMP lt f gt HEAD FANCONT TEMP This command sets the temperature set point for the fan control the setting has no effect if no fan is connected The command is rejected if the fan operation mode is s
37. STAT APORT SIGNAL This command reads the status of the analog interface pins Use this command to query the activity level of the individual signals applied to the analog port refer to Table B 6 Individual bit position 1 signal on pin is active Individual bit position 0 signal on pin is not active Example gt STAT APORT SIGNAL lt CR gt lt 64 lt CR gt lt LF gt Standby line is active STAT COND CMD This command reads the status of the last command refer to Table C 2 Example gt STAT COND CMD lt CR gt lt 0 lt CR gt lt LF gt The last command was successfully completed STAT COND EVEN This command reads system events status refer to Table C 2 Example gt STAT COND EVEN lt CR gt lt 4 lt CR gt lt LF gt Keyswitch is in OFF position STAT COND OPER This command reads system operational status refer to Table C 2 Example gt STAT COND OPER lt CR gt lt 8 lt CR gt lt LF gt System is in SLEEP mode STAT COND SYST This command reads the system status refer to Table C 2 Example gt STAT COND SYST lt CR gt lt 2 lt CR gt lt LF gt There is a laser head fault B 32 Serial Commands and Queries STAT COND SYST APORT This command reads analog interface status refer to Table C 2 Example gt STAT COND SYST APORT lt CR gt lt 1 lt CR gt lt LF gt Missing EXTERNAL_DIODE_ON s
38. active 1 Only EXPL xxx yyy E models Only EXPL xxx yyy P models 6 3 Explorer Actively Q Switched High Repetition Laser Systems Sleep Mode If the system enters Sleep mode most commands become inactive For safety reasons this can happen if one of the temperature controllers fails for example The Emission button is deactivated and Sleep Mode is dis played in the Emission control field see Figure 6 2 Tools View Power Control Temp Control Settings e ad S Spectra Physics L Win LASER CONTROL 1 2 0 Emission SPECTRA PHYSICS EXPLORER 532 1000 100KP PV 0080 B amp 2 ENG P5 0272 B02 ENG V4 00 39Q 100 Sleep Mode V400 111 PEE or S Standby Utilities Control Pump Repetition Rate mode Current set r Trigger ana RS joo 0 00 A a 232 7 internal Paena measured Y current set 0 0 4 Set Jo emission Average Power mW command error TT system error 1 1 1 std event 500 i000 1500 2000 iA System Status Error Laser Diode Temp RS 232 comm error 23 Figure 6 2 Sleep Mode Sleep mode can be activated by using the software command Mode Sleep 1 To exit Sleep mode use the command Mode Sleep 0 or turn the power supply off then on if the unit was put into Sleep mode by the system itself Operating Using the L Win Software Saving and Using Pre Set Operating Parameters Note Gwin uns Power Control Temp Control Settings
39. actual error code X X X X X x READ FAULT HIST READ FAULT LIST STB read error code history FIFO list of 16 entries return list of all active error codes max 16 read status byte STAT COND CMD read serial command status TAT COND OPER STAT COND SYST read system status STAT COND EVEN read events status read operational condition status S STAT COND SYST PARSET S read parameter set status load storage TAT COND SYST PSUPPLY read powersupply status STAT COND SYST HEAD read laserhead system condition STAT COND SYST DIOD1 read laserdiode condition TAT COND SYST TCONT read temperature controller condition S STAT COND SYST APORT STAT COND SYST SOFT read analog port condition return software exception status STAT COND SYST COMPAT return hardware software compatibility status History Pulse Counts Operating Hours READ HEAD HOUR READ PSUPPLY HOUR READ QSW CNTS read laserhead ON time read power supply ON time read actual pulse counter x x x ENEEEEN Io es os E LL LLLI LLL LLLI LL I LLLI L ILLI L ILLI 1 READ DIOD1 HOUR Auto On Feature CONT AUTOON n CONT AUTOON Configuration Parameter Sets CONFIG PARSET BOOT n CONFIG PARSET BOOT CONFIG PARSET STOR n CONFIG PARSET LOAD n read diode operating hours set AUTO ON feature on off read the AUTO ON setting set parameter set n when
40. also provides a status output that can be used to drive an emission indicator Refer to Table 7 2 on page 7 16 for a com plete description of these pins and to The Analog Interface on page 7 15 for instructions on how to use this connector to control advanced features of the Explorer laser Controls Indicators and Connections RS 232 input connector 9 pin D sub female provides attachment for a serial cable from a control device such as a personal computer Refer to Table 4 1 below for a complete description of these pins and to Serial Communication on page 7 2 for instructions on how to control the laser using this connector 5 1 00000 o0ooo 9 6 Figure 4 5 The 9 Pin RS 232 Port Connector Table 4 1 IBM PC AT Serial Port Pinout Computer or Terminal L Series RS 232 C Signal Pin No Pin No Pin No Signal Signal Name 25 Pin 9 Pin Transmit Data TXD 2 3 3 RXD Receive Data RXD 3 2 2 TXD Signal Ground 7 5 5 Protective Ground 1 SHELL SHELL DC IN power connector 8 pin high current connector female provides attachment for the cable from the 24 2 Vdc 4 A electrical source with a current ripple of lt 100 mV rms The DC IN power connector is an 8 pin DIN 45326 socket Table 4 2 below describes the pins of this interface Pins 6 and 7 of this connector form a floating relay that can be used to con trol an external emission indicator An internal relay switch is closed when e
41. and pin 13 INTER LOCK active indicator must be high otherwise laser emission is inhibited Once pin 10 has gone low pin 9 the EMISSION indicator reports active low immediately and laser emission occurs about 3 seconds after activat ing pin 10 If pin 9 does not report active low immediately after activating pin 10 an internal system error may have occurred Refer to the trouble shooting procedures provided in Chapter 8 for resolution The output of pin 11 can be used to control an emission indicator Refer to Figure 7 4 for an example of a circuit that implements this function Using the Control Inputs An example of a simple circuit used to pull one of the Explorer analog pins low is shown in Figure 7 3 Note that pin 24 is the ground pin on the ANALOG IN connector This circuit can be used with pin 10 to turn on the diode laser It can also be used with other pins that are described later in this section 45V Pin 10 2 Diode Laser ON Pin 15 Standby Mode Pin 17 Gate Pulses Active Level Pin 21 External Trigger Input Command S 5 l o o i 7 A gt c d x N Pin n lt 9 ANN o o 7AACTxx Oo n Input A D Pin 24 Gnd a Oo 0 o Gnd m Di id L SERIES External Circuit Figure 7 3 Laser Control Circuit Example Operating with Commands and Signals Adjusting the Pump Diode Current Using Analog Signals Pin 2 of the ANALOG IN port can be used to adjust the diode laser current
42. c eee 3 14 Figure 3 11 Interlock Safety Block Diagram 0 0 0 ccc tees 3 15 Figure 4 1 Explorer Laser Head Emission Indicator 0 0000 eee eee eee 4 1 Figure 4 2 Explorer Laser Head Rear Panel Connections 00 0c eee eee eee 4 2 Figure 4 3 Power Supply Front Panel 00 0c cece eet 4 3 Figure 4 4 ANALOG IN Connector 00 000 cect eee 4 4 Figure 4 5 The 9 Pin RS 232 Port Connector 00000 c cee teens 4 5 Figure 4 6 DC IN Power Connector 0 0c cee eee ee 4 5 Figure 4 7 Power Supply Rear Panel lslsselessese tetas 4 6 Figure 5 1 Laser Head Heatsink Thermal Impedance Requirement 20 00s eee 5 1 Figure 5 2 Air Flow through the Spectra Physics Heatsink 0 00 e eee eee eee 5 2 Figure 5 3 System Interconnect Drawing 0 0c cece ett eee 5 3 Figure 5 4 The L Win Power Control Display 0 0000 cece eee ee 5 6 Figure 6 1 The L Win Main Display 00 0 0 eee 6 2 Figure 6 2 Sleep Mode sssssesseeesellell eet 6 4 Figure 6 3 Settings Tab Selecting Operating Parameters lllllies lisse 6 5 Figure 6 4 Tools Menu Accessing the Energy Statistics Display llis ilis 6 6 Figure 6 5 Energy Statistics Display 2 0 0 0 0c ne 6 7 Figure 6 6 Settings Tab Calibration Factor liliis res 6 8 Figure 6 7 Tracking Operating Hours l sssiselseseee tenes 6 9 Figu
43. calibration factor output of query PENER CALF Examples gt READ PENER HIST lt CR gt 455 772 781 776 776 778 773 lt CR gt lt LF gt gt READ PENER HIST lt CR gt lt 0 lt CR gt lt LF gt No pulses have been emitted yet READ POW This command reads the actual laser power in mW EXPL xxx yyy P models only Unit mW Example gt READ POW lt CR gt 21mW lt CR gt lt LF gt READ PSUPPLY HOUR This command reads the power supply hours Power supply hours are incremented every 6 minutes 0 1 hour that power is supplied to the power supply Unit HrsPS Example gt READ PSUPPLY HOUR lt CR gt lt 478 7HrsPS lt CR gt lt LF gt The power supply has been supplied with power for 478 7 hours READ QSW CNTS This command reads the pulse counter in kilocounts or megacounts depending on Explorer model Unit kcnts or ments Examples gt READ QSW CNTS lt CR gt 34121kcnts lt CR gt lt LF gt The system has issued 34 121 000 pulses READ SHG TEMP This command reads the measured SHG temperature in counts Unit cnts B 31 Explorer Actively Q Switched High Repetition Laser Systems Example gt READ SHG TEMP lt CR gt 1649cnts lt CR gt lt LF gt READ THG TEMP This command reads the measured THG temperature in counts Unit cnts Example gt READ SHG TEMP lt CR gt 2989cnts lt CR gt lt LF gt
44. incident light Using frequency doubling as an example the crystal is oriented so that it produces a frequency doubled beam with a polarization orthogonal to that of the fundamental beam The doubled beam is the extraordinary ray which has a refractive index that depends on the path it takes through the crystal The crystal can than be rotated into a position where the refractive indices for the fundamental and the frequency doubled beams are the same So called non critical phase matching relies on the temperature depen dence rather than the angular dependence of the refractive index of the extraordinary ray The crystal is heated to a point where the refractive index for the extraordinary ray equals the index for the ordinary ray Thus the fundamental and harmonic wavelengths remain in phase As the name implies non critical phase matching is much less sensitive to the alignment of the crystal Lithium triborate LBO is a nonlinear optical crystal characterized by a relatively high optical damage threshold a good nonlinear optical coeffi cient and excellent material properties The optical qualities of an LBO crystal allow for non critical phase matching and its large acceptance angle results in high efficiency frequency conversion The crystal is heated and temperature stabilized to maintain good efficiency Second harmonic generation or frequency doubling is a nonlinear optical effect that takes place when a large frac
45. incremented every 6 minutes 0 1 hour that the diode laser is turned on Emission mode or in Standby mode Unit HrsD1 Example gt READ DIOD1 HOUR lt CR gt 234 8HrsD1 lt CR gt lt LF gt The diode laser has been operated for 234 8 hours Analog Interface CONFIG APORT POLAR lt n gt CONFIG APORT POLAR This command sets the polarity of the analog interface lines refer to Table B 5 Range n 0 511 Individual bit position 1 line is high active rising edge Individual bit position 7 0 line is low active falling edge default Examples gt CONFIG APORT POLAR 96 lt CR gt Set polarity of pins EXTERNAL_DIODE_ON and STANDBY to high active lt lt CR gt lt LF gt gt CONFIG APORT POLAR CR 96 lt CR gt lt LF gt STAT APORT SIGNAL This command reads the status of the analog interface pins Use this command to query the activity level of the individual signals applied to the analog port refer to Table B 5 Individual bit position 1 signal on pin is active Individual bit position 0 signal on pin is not active Example gt STAT APORT SIGNAL lt CR gt lt 64 lt CR gt lt LF gt Standby line is active B 8 Serial Commands and Queries Pulse Energy Commands related to pulse energy are only valid for EXPL xxx yyy E models READ PENER This command reads the actual pulse energy in pJ Unit uJ Example READ PENER CR
46. mode is activated No action is required Explorer Actively Q Switched High Repetition Laser Systems Table C 2 Operating Status and Error Bits Continued Bit ana 2 Active Description Condition Action Required 12 LASER WARMUP Laser system is warming up No action is required If an automatic pulse energy adjustment is to be performed it is recommended to wait until this bit is cleared typically 10 minutes after a cold start or 2 minutes after a warm start 13 PULSE ENERGY SETTING An automatic pulse energy No action is required adjustment is taking place 14 BURST ENABLED Burst mode is enabled i e To perform a burst enter the burst counts is set to lt n gt BURST command To disable counts the burst mode set the burst counts to O 15 ANALOG ENABLED The Explorer laser system is in The laser may be switched on analog mode and off applying appropriate electric signals to the analog port pins To disable the analog mode enter the command MODE RMT 0 System Condition Parameter Set Register Query STAT COND SYST PARSET 0 ERROR LOAD PS GLBL An error occurred while retriev Contact Spectra Physics service ing global data from the power supply EEPROM 1 ERROR LOAD PS USER An error occurred while retriev Contact Spectra Physics service ing the actual user parameter set from the power supply EEPROM 2 ERROR LOAD PS HISTORY An error occurred when Contact Spectra Physics service retrieving from the
47. n2 gt lt n3 gt This command starts an automatic pulse energy adjustment The setting procedure lasts about 10 seconds lt n gt requested pulse energy in uJ The range of n4 depends on the Explorer model See Table B 3 lt n gt pulse repetition rate PRF for which the adjustment is to be executed see Table B 3 for the valid PRF range na determines if the automatically adjusted parameters are stored or not after completion of the setting procedure n 0 The diode laser current is set to the adjusted current but not saved to the internal EEPROM These settings can be manually stored by the user CONFIG PARSET STOR lt n gt This requires that the laser emission is disabled n 1 orn 2 The settings are automatically stored in the user set 1 or 2 respectively Note 1 The command is rejected if the laser is not switched on During the adjustment procedure queries about the diode current pulse repetition frequency and temperatures are not valid Note 2 During the adjustment procedure the status may be queried using the command STAT COND OPER and checking if bit 13 Power setting is activated CONT PENER 0 stops a launched adjustment procedure Examples gt CONT PENER 20 50000 1 lt CR gt Request to set the pulse energy to 20 uUJ 50kHZz After completion the found parameters diode current are stored in the user parameter set 1 lt lt CR gt lt LF gt gt CONT PENER 10 50000 1 lt CR gt Request to set
48. optic Q switch 3 1 Explorer Actively Q Switched High Repetition Laser Systems End Output Mirror Coupler i xr Al Diode B 7 Laser SHG THG Laser Crystal Crystal Q Switch Crystal Telescope SaS om Sealed Cavity Output Beam Figure 3 1 Optical Design of the Explorer Laser Head The Q switched output of the IR laser beam is converted to shorter wave lengths inside the laser head by means of nonlinear optical crystals Frequency Doubling and Tripling Materials with certain crystalline properties will transform a fraction of intense incident laser light into coherent light output at shorter wave lengths For efficient conversion care must be taken to keep the incident beam and the converted beam in phase within the crystal The intense pulses produced by Q switching are much more efficient than a continuous laser beam at producing the shorter wavelengths obtained through this non linear harmonic generation also referred to as frequency conversion Green output at 532 nm is generated by frequency doubling the fundamen tal IR laser output at 1064 nm in a crystal of lithium triborate LBO a pro cess also referred to as second harmonic generation SHG The nonlinear wavelength conversion takes place entirely inside the laser head A spe cially coated mirror directs the green light out of the laser cavity while con fining the infrared wavelength inside Ultraviolet output at 355 n
49. orbitals lille D 2 Figure D 2 Typical Four level Transition Scheme 000 00 e eee eee eee D 3 Figure D 3 Frequency Distribution of Longitudinal Modes for a Single Line D 4 Figure D 4 Energy Level Scheme for the Nd lon lliilllesesessse eee D 5 Figure D 5 Nd absorption spectra compared to emission 2 0 0 0 0c cence D 6 Figure D 6 Mode Matching seesi aerae panne WEE Na EEE E e m aR Aa D 7 Figure D 7 An Intracavity Acousto Optic Modulator ssa sasaaa aaaea D 9 List of Tables Table 1 1 High Repetition Rate Explorer OEM Models 0000 0c cece e eens 1 2 Table 2 1 Maximum Emission Levels from Laser Head 2 5 Table 2 2 Label Translations 0 0 0 hen 2 8 Table 3 1 Explorer Performance Specifications sasaaa cae 3 10 Table 3 2 Electrical and Cooling Specifications 0 0 0 0 cee ee 3 11 Table 3 3 Dimensions and Weight 0 cee e eh 3 11 Table 4 1 IBM PC AT Serial Port Pinout 0 0 000000 4 5 Table 4 2 DC IN Power Connector Pinout 0 0 0000 cece tees 4 5 Table 4 3 FAN Connector Pinout 0 000 c tees 4 6 Table 7 1 System Response to Over Temperature Conditions 0000 0c een eee 7 10 Table 7 2 ANALOG IN Pin Description 0 0 000000 eet 7 16 Table 7 3 Operating Mode Summary 000 0c cette tees 7 22 Table 8 1 Field Replaceable Units 0 0 0 eee 8 7 Table C 1 System Statu
50. power supply is turned on the keyswitch is on and the laser has warmed to operating temperature If you are uncertain about the status of the laser return to Chapter 5 and verify that it has been installed correctly and that L Win is operating LabView is a trademark of National Instruments Inc 6 1 Explorer Actively Q Switched High Repetition Laser Systems Basic Operating Control Turning the Laser On and Off This procedure assumes that the laser is already at operating temperature a warm start condition If this is not the case follow the procedure in Ini tial Turn On Turn Off Using the L Win Software on page 5 5 for starting the laser from a cold start condition If not already active enable the Power Control display by clicking on the Power Control tab near the menu bar See Setting the Auto On Mode on page 6 5 for a description of the inter action of the keyswitch on the L Series power supply with the functionality of the software Tools View D Power Control Temp Control Settings serial port G Spectra Physics L Win ASER CONTROL v1 2 0 Emission ISPECTRA PHYSICS EXPLORER 532 1000 100KP PV 0080 B62 ENG P5 0272 B02 ENG V4 00 33Q 100 Emission Control V4 00 111 Seri Utilities Terminal Standby Control f i f m Control Pump Repetition Rate d nci Current set Tracer Diode Laser o gt B ee og 232 internal external Pump Current ce Pulse Rate Setting Pulse Energy Read
51. setting other temperature limits Alternatively the thermal servo loop can be deactivated via serial com mand and the fan speed set by the user This allows the heatsink to be con trolled by the operator through the L Series power supply interface Air Inlets Laser Oc o e ol Alignment Pin 2 amp x A oO Explorer E 9 2 Head SI E LLI 2 o z Alignment pin Thermal Washer Fan Connector Fan Connector Air Cable Outlets Figure 5 2 Air Flow through the Spectra Physics Heatsink 5 2 Installation Mounting the Hardware Following standard practice mount the laser head on a suitable heatsink as described in the preceding section Warning Never use thermal grease when mounting the laser head on the heatsink This will contaminate the laser package and the output window Use three 8 32 SAE or M4 metric bolts and washers to mount the laser head Tighten the bolts and torque them to 1 N m 9 in Ib Refer to Out line Drawings on page 3 12 for dimensions and hole locations Using the slots shown in Figure 3 9 mount the power supply to a suitable surface using four 4 20 SAE or M6 metric bolts and washers Connecting the System Refer to the Interconnect Drawing in Figure 5 3 to connect the Explorer laser system components Power Supply Front Panel O POWER O EMISSION CERRO DC Power Source Host Serial Control
52. that DC power is being supplied to the laser head EMISSION indicator blue illuminates to indicate that laser emission is present or imminent This happens right after the keyswitch is turned on and an appropriate serial On command or analog signal is provided ERROR indicator red turns on when the software has detected an error condition It is normal for this indicator to turn on when the power switch is turned on and it will remain on for about 5 minutes during the warm up sequence from a cold start condition Front Panel Connections 4 4 Note S Warning m ANALOG IN connector 26 pin D sub HD male provides attachment for a control cable to an analog control device The female mating connector is TYCO AMP 1658682 1 housing RoHS compliant using pins TYCO AMP 1658686 1 crimp socket RoHS com pliant ANALOG IN Figure 4 4 ANALOG IN Connector In order for the laser to turn on pins 7 and 8 of this connector must be shorted together either directly as when using the supplied shorting jumper or through a user supplied normally closed interlock switch This connector is identical to the LASERHEAD 2 connector on the back of the laser head Interchanging the cables to these connectors may cause damage to the laser Among its many functions this connector can be used to provide an inter lock to turn off laser emission in the event that a safety switch is opened unexpectedly This connector
53. the emission indicators The laser has a watchdog timer that if enabled turns off the laser if it does not receive a communication from the host computer within a user speci fied interval The default setting for the watchdog timer is OFF Set the watchdog timer interval using the following command WDOG n where n interval time from 0 to 110 seconds WDOG 0 turns off the watchdog timer To query the status of the watchdog timer enter WDOG 25 where 25 is the interval time in seconds 7 3 Explorer Actively Q Switched High Repetition Laser Systems Adjusting the Pulse Energy or Average Power To read the actual pulse energy in uJ use the query READ PENER To read the actual average power in mW use the query READ POW To change pulse energy adjust the diode laser current using the command DIOD1 CURR lt f gt where lt f gt is a decimal value for current in Amps Example DIOD1 CURR 4 56 READ DIOD1 CURR 4 56 diode current 4 56 A DIOD1 CURR returns the value last commanded The current can also be set as a percentage of its maximum allowed value thus allowing the operator to change the current relative to its present value Use the following command to change the current as a percentage of maxi mum current PCUR f where f is a decimal value for the percent of maxi mum current In necessary the maximum current value can be found using the query DIOD1 MAXC returns the di
54. the parameter sets listed above Use CONFIG PARSET STOR 1 or CONFIG PARSET STOR 2 to make this setting permanent 7 7 Explorer Actively Q Switched High Repetition Laser Systems Setting the Auto On Mode Warning M Auto On mode overrides the need for a keyswitch reset i e turning the keyswitch off then back on to turn the system on using only serial com mands This is the normal mode for operating the laser using remote con trol To enable Auto On mode enter the command CONT AUTOON 1 To disable Auto On mode enter the command CONT AUTOON 0 To return the status of Auto On mode enter the query CONT AUTOON Over riding the keyswitch does not comply with CDRH regulations With Auto On enabled and the keyswitch in the ON position the laser can be turned on using software commands without having to switch the keyswitch off and on again Laser System Settings Configuring Analog Control Serial commands can be used to configure and monitor the individual pins of the ANALOG IN connector Refer to The Analog Interface on page 7 15 for a description of the ANALOG IN connector The serial commands and queries act on an 8 bit Analog Port Status Byte where each bit corresponds to a particular laser function controlled by an analog signal If a bit in the Analog Port Status Byte is set to 1 the corresponding ana log signal is either set to high for a command or is read as high in respo
55. the window FPS and Burst Control Display SiBurst Mode CFG vi O x Laser Serial Port Pulse Energy Eom Pulses l Burst Jj 50 FPS Delaytime us Jizd Repetition Rate Hz Ji 50000 Waveform Graph isPuse EM ist Pulse uJ Other Pulses AG 14 24 1st Pulse Error in 27 g Pulse Ener Pulses 2nd to end mean 14 64 sigma in 95 Waz Pump Current A Jen L 1 I 1 1 1 L 1 at iy at er 3I ayo i a Pulses Graph Displa c Status Burst done Loop Time ms Jj 200 Figure A 15 FPS and Burst Control Display The FPS and Burst Control display is used to adjust the First Pulse Sup pression parameter FPS Delay Time in such a way that the first pulse has approximately the same energy as subsequent pulses Note this display only applies to EXPL xxx yyy E lasers Laser Serial Port field shows the active serial port for communica tion with the system A 14 L Win GUI Reference Pulses Burst field sets the number of pulses per burst FPS Delay Time field sets the FPS delay interval in microsec onds This value can be varied until either the red bar which repre sents the first pulse in the Waveform Graph is approximately the same height as the other bars or the First Pulse Error is about 0 Repetition Rate field sets the pulse frequency repetition rate in Hertz Pump Current field sets the current of the diode pump laser in Amps Status field d
56. to a percentage Changing the pump current can affect other aspects of the laser perfor mance Refer to Important Notes on Controlling Explorer Output on page 6 17 for more information The energy of individual pulses or the average power can be read from the pulse monitor on the status panel at the bottom of the Main display Figure 6 1 The status panel readings are updated once a second Changing the Pulse Repetition Rate To change the pulse repetition frequency click on the up down arrows to the left of the Set field of the Repetition Rate section of the display or type a value directly into the text field Using L Win the repetition rate can be varied depending on the Explorer model from single shot to 60 kHz or from 20 kHz to 150 kHz there may be a small difference between the set rate and the actual repetition rate refer to Changing the Pulse Repetition Frequency on page 7 5 for more information Note that external triggering is also available Refer to External Q Switch Triggering on page 7 19 for more information Setting the Laser to Standby Click on the Standby button to set the diode laser to standby current which is below the threshold for Explorer lasing This extends diode laser lifetime when the laser is inactive but it keeps the laser at operating temperature for immediate use Clicking this button again will return the system to normal operation This button turns yellow when Standby mode is
57. whether the user parameters will be stored after completion If this procedure is successful the diode current and repetition rate are set as the new input values if internal triggering mode is on This can be ver ified by using the command CONT POW which displays the new diode current and power If this procedure fails the command CONT POW displays a question mark 4 Review the chart in Figure 3 4 on page 3 7 to make sure the laser is capable of delivering the power requested for the given pulse frequency See Table B 3 for the valid n range Operating with Commands and Signals The Analog Interface Caution n ANALOG IN Figure 7 2 The 26 Socket ANALOG IN Connector The L Series 26 pin D sub ANALOG IN port is used to control the laser sys tem via user supplied DC voltages and or TTL level signals In order for the system to operate pins 7 and 8 must be shorted together either directly using the supplied shorting jumper plug or through a user supplied normally closed interlock switch The ANALOG IN interface accommodates a variety of control modes and timing requirements and it is used in conjunction with serial commands that are executed through the RS 232 interface The ANALOG IN interface provides the following controls e laser on off e standby mode e diode laser current set e safety interlock emission output e ready and fault indicators e pulse energy monitor average power monitor
58. 0 kHz Measured at 50 kHz and nominal average power Measured at 10 kHz and nominal average power Range varies with models 7 Specified at the beam waist with beam diameter at 1 e2 points Diameter at 1 e2 full angle Cold start to gt 95 of full power 3 10 The Explorer Laser System Table 3 2 Electrical and Cooling Specifications Operating voltage Power consumption typical maximum Maximum inrush current Cooling L Series power supply Explorer Laser head Laser head thermal heat dissipation Operating temperature lt 80 relative humidity Laser head Power supply Storage temperature lt 90 relative humidity non condensing 24 Vdc 2 V lt 50 W 25 C lt 75 W lt 4A Air cooled Air and conduction cooled lt 40 W 18 to 35 C 18 to 35 C 20 to 60 C Table 3 3 Dimensions and Weight Explorer Laser Head Size L x W x H Weight typical L08 Power Supply Size Lx W x H Weight typical Laser Head Cable Length 165 x95 x 54 mm 6 50 x 3 74 x 2 13 in 1 2 kg 2 64 Ib 164 x 130 x 66 mm 6 46 x 5 12 x 2 56 in 0 9 kg 2 0 Ib 2 0 m 6 ft Length is approximate flexible 5 m cable available on request 3 11 Explorer Actively Q Switched High Repetition Laser Systems Outline Drawings Reference Pin 3 places 4 5 mm 3 places e ajin gt e Emission Indicator
59. 24 25 12 lt CR gt lt LF gt STB This command reads the system status byte refer to Table C 1 Example gt STB lt CR gt lt 1 lt CR gt lt LF gt Laser emission is present Explorer Actively Q Switched High Repetition Laser Systems STAT COND CMD This command reads the status of the last command refer to Table C 2 Example gt STAT COND CMD lt CR gt lt 0 lt CR gt lt LF gt The last command was successfully completed STAT COND SYST This command reads the system status refer to Table C 2 Example gt STAT COND SYST lt CR gt 2 CR LF There is a laser head fault STAT COND SYST PARSET This command reads data administration status refer to Table C 2 Example gt STAT COND SYST PARSET lt CR gt lt 16 lt CR gt lt LF gt An error occurred while loading the user parameter set STAT COND SYST PSUPPLY This command reads power supply status refer to Table C 2 Example gt STAT COND SYST PSUPPLY lt CR gt lt 1 lt CR gt lt LF gt There is an overtemp condition on the power supply board STAT COND SYST HEAD This command reads laser head status refer to Table C 2 Example gt STAT COND SYST HEAD lt CR gt lt 1 lt CR gt lt LF gt There was a communication error with the laser head STAT COND SYST DIOD1 This command reads diode laser status refer to Table C 2
60. 32 nm wavelengths might also be present The Explorer laser must be started initially using either the serial com mands outlined in this chapter or the L Win software described in Chapter 6 Once the Explorer system is turned on it can also be controlled using signals applied to the ANALOG IN interface on the L Series power supply or through a combination of serial commands and analog signals Maximum control of laser output is provided by combining the flexibility of serial commands with the speed of analog signals Note The procedures in this chapter assume that the Explorer laser has been installed according to the instructions in Chapter 5 This means that the laser was installed with proper attention to heat removal the laser head power supply and computer were properly connected and that DC power is supplied to the power supply the interlock relay and emission circuits if installed are properly wired or the jumper plug is installed the power supply has been turned on the keyswitch is on and the laser is warmed up to operating temperature If you are uncertain about the status of the laser return to Chapter 5 and verify that it has been installed correctly Appendix B lists all of the serial commands and analog signals available to the user This chapter provides instructions and examples on how to use some of these commands and signals to control laser output 7 1 Explorer Actively Q Switched High Re
61. 355 300 E ICT 355 300 P Explorer 532 nm DPSS Laser Head single shot 60 kHz 20 kHz 60 kHz 20 kHz 150 kHz L Series Power Supply 8A ICD 532 200 E ICD 532 1W E ICD 532 2W E ICD 532 1W P ICD 532 2W P Extended Model PS L08 Where XX is 0520 5 m l0 1 m 20 2 m and 50 5 m Explorer Actively Q Switched High Repetition Laser Systems Customer Service Warranty 8 8 At Spectra Physics we take great pride in the reliability of our products Considerable emphasis has been placed on controlled manufacturing meth ods and quality control throughout the manufacturing process Neverthe less even the finest precision instruments will need occasional service We feel our instruments have excellent service records compared to competi tive products and we hope to demonstrate in the long run that we provide excellent service to our customers in two ways first by providing the best equipment for the money and second by offering service facilities that get your instrument repaired and back to you as soon as possible Spectra Physics maintains major service centers in the United States Europe and Japan Additionally there are field service offices in major United States cities When calling for service inside the United States dial our toll free number 1 800 456 2552 To phone for service in other coun tries refer to Service Centers on page 8 10 Order replacement parts directly from Spectra Physics Fo
62. 4 am Reserved 5 m POWERSUPPLY 5 gt STANDARD EVENT 6 EC37 Reserved 7 m gt OPERATIONAL 8 Ec45 HW SW MISMATCH 14 SWEXCEPTION 15 ls A P STATus CONDition EVENts 2 x userntertock o Jecie KEY INTERLOCK 1 EC13 1 KEYLOCK 2 Ecae Zine SYSTEM BOOT 3 2 EOM SOFTWARE WATCHDOG 4 oRd 4E HARDWARE_WATCHDOG 5 4 5 EC23 od 6 EC24 25 15 J 15 J STATus CONDition OPERational STANDBY_ACTIVE 0 o ec BURST BUSY 1 1 Eca2 Reserved 2 ORd SLEEP MODE 3 CW MODE 4 cate 5 15 J EXTERNAL_DIODECURRENT 6 SYNC_OVER_BURST 7 OR d Reserved 8 o RANDOM PULSING MODE 9 1 EXTERNAL TRIGGER 10 ORd FIRST PULSE SUPPRESSION 11 LASER WARMUP 12 PULSE ENERGY ADJUSTMENT 13 15 Jj BURST ENABLED 14 ANALOG ENABLED 15 9 0 Jecssise 1 EC383 38 OR EXPLORER Status Error Reporting Command 15 J A EC Error Code Command READ FAULT o Ecas i 2 Ecae 3 Ecae OR 4 EC36 15 J ORd 15 J o s o o 5 o w Serial Commands and Queries Table B 5 Analog Port Polarity Configuration Bits Bit Description Signal Default Setting 0 Sync out Low active falling edge 1 Pulse monitor Low active falling edge 2 External trigger Low active falling edge 3 External gate Low active 4 reserved N A 5 X External standby Low active 6 External diode on Low active falling edge 7 reserved N A 8 External diode current source
63. 750 To optimize laser performance using the FPS feature the recommended start value is the inverse of the applied pulse repetition frequency For example if the PRF is 20 kHz the recommended FPS starting value is 50 us FPS DELAY lt n gt sets the FPS delay time where lt n gt is an integer value in microseconds up to 2000 Example FPS DELAY 50 FPS DELAY reads the value of the FPS delay time FPS DELAY 0 exits FPS mode When an external trigger is used for the Q switch FPS mode must be enabled separately as well Refer to Appendix B for details For laser heads without an internal pulse energy detector the user must measure the pulse energy of the first pulse using an external meter How ever the adjustment of the FPS delay time is the same as described above Automatic Pulse Energy or Power Adjustment The automatic pulse energy or average power setting procedure allows the diode laser current to be automatically adjusted to achieve the desired pulse energy or output power see Table B 3 for the ranges of automatic energy or power adjustment Note that maximum output power or pulse energy varies with the pulse repetition rate as shown in Figure 3 4 and Figure 3 5 on page 3 7 The duration depends on the model and the requested pulse energy or power The maximum duration is 50 seconds To use this feature 1 Turn on the laser using either the ON command computer mode must be activated or an external signal appl
64. 9 Specifications 2 32 dei ead te Mt REST Egon DPA edat Re Ves maed ed in e 3 10 Outline Drawings 5 oie ce iene when ace ar e DR FRATRI ERR US eU QNT te PORA ea ey 3 12 Interlock Block Diagram smise e ara e a AA A RR 0e rr 3 15 Chapter 4 Controls Indicators and Connections 4 1 The Explorer Laser Head dari ca ees coe sh ie EY eR st eal ER X RT ERES 4 1 Gontlols v iom our eue RR we AA REGU aes See CO I b doi ESOS 4 1 IridiCatorS 2 5 6 eae eh Eee cx AE e D DOPERENECRUPDATPSmeCh Led ELT 4 1 Connections esek be Beeches dha pass de RERO REPOS PNE E e epu Ed peu dara 4 2 The L Series Power Supply 0 000 shes 4 3 Front Panel Controls aue xr dew ERREUR RR CUR cede etat dte eat e dea p eaa 4 3 Front Panel Indicators i2 csse dee eta whe dete eed Lee gg e zn4 e d ewe RT 4 4 Front Panel Connections lissseseeselee hh 4 4 Rear Panel Connections oye ca neck XE ee eR ege ck eue deque p eR 4 6 Chapter 5 Installation 2 erre ronem xim Roe on ee RR 5 1 Thermal Management srda roa dp eies eO a tenes 5 1 Mounting the Hardware 0 0 ccc teens 5 3 Connecting the System 0 ccc eee ae 5 3 Laser Alignment 2 Ree Be ae eek ac gr e og dae Rete WE De ee 5 4 Initial Turn On Turn Off Using the L Win Software sslsssee ree 5 5 Installing the L Win Software llsisesselseslele tenes 5 5 Setting Up Initial L Win Communications 0 0 0000 00 cette 5 6 TUE Of esee
65. A to pin 17 A timing diagram for Methods A and B is shown in Figure 7 8 7 23 Explorer Actively Q Switched High Repetition Laser Systems Voltage Pin 17 Laser pulse Voltage Pin 17 Voltage Pin 21 Laser pulse Method A Jo Ld L AUUE Ub Pe Delay is not defined Method B Tdo LJ L EM User specified delay UUL UUL L 300 ns delay Figure 7 8 Timing Diagrams for Methods A and B Advanced Control of the Pulsed Output Figure 7 9 and Figure 7 10 illustrate the timing relationships using either Standby pin 15 or Gate pin 17 to control internal triggering Figure 7 9 shows operation using FPS but not Burst mode while Figure 7 10 shows operation using both FPS and Burst Gating The laser output pulses can be shut off by pulling pin 17 low Figure 7 3 shows an example circuit The External Gate must provide at least 1 us prior to the estimated start of the optical pulse until at least 1 us after the estimated end of the optical pulse Burst Output Burst mode timing is illustrated in Figure 7 10 on page 7 26 7 24 Operating with Commands and Signals 6L uld LNO ou S uiJ8 X3 indino Jose pes ndg i Aeled Sd4 srl ul eun Av13q Sd4 AGGLS eurejxe AALS jeujejurueu ejeg swz E SWZ uey 136u0 AALS Ieuja1xo JI H Jeu491u queuing Jose opoiq AALS JeuJ91u Jo31uo2 jeu4o1u suoot lt le gt
66. D DIODE1 HOUR Example READ DIODE1 HOUR 456 2HrsD1 total operation time is returned in hours Changing the Pulse Repetition Frequency The QSW PRF command sets the pulse repetition frequency PRF To set the pulsed output to 50 kHz for example enter the command QSW PRF 50000 To return the last commanded value for the PRF enter the query SW PRF To return the present value of the PRF enter the query READ QSW PRF Because of the minimum interval of the timer clock there is an inaccuracy regarding the frequency adjustment However the real frequency fpa can be calculated from the adjusted frequency faq using the following equa tion 4 MHz 4 MHz Jadi The command READ QSW PRF returns the real frequency The maximal difference between the real frequency and the adjusted frequency can be calculated from the equation f real round 4 MHz Af s max ius zx 4 MHz t 0 5 Sea The correction is shown graphically in Figure 7 1 7 5 Explorer Actively Q Switched High Repetition Laser Systems Discrepancy to Real Pulse Rep Rate kHz 0 20 40 60 80 100 120 140 Adjusted Pulse Repetition Rate kHz Figure 7 1 Repetition Rate Correction Setting the Laser to Standby or Sleep Mode 7 6 There are two Standby modes for the Explorer laser Standby and Sleep The modes differ in the time required for the laser to return to normal oper ation and the a
67. EEPROM the accumulated seconds that the power sup ply has been supplied with power 3 ERROR LOAD HEAD GLBL An error occurred when Check the cable connection retrieving the laser head glo between the power supply and bal data from the laser head laser head EEPROM Contact Spectra Physics service 4 ERROR LOAD HEAD USER An error occurred when Check the cable connection retrieving the actual user between the power supply and parameter set of the laser laser head head from the laser head Contact Spectra Physics service EEPROM 5 ERROR LOAD HEAD HISTOR An error occurred while retriev Check the cable connection Y ing the diode laser operating hours and the pulse counts from the laser head EEPROM between the power supply and laser head Contact Spectra Physics service C 4 Table C 2 Operating Status and Error Bits Continued Operating Status Codes Bit Active Description Condition Action Required 6 ERROR_STORE_LOAD_PS_ GLBL ERROR_STORE_PS_USER An error occurred while storing global data to the power sup ply EEPROM An error occurred while storing the actual user parameter set to the power supply EEPROM ERROR STORE PS HISTORY An error occurred while storing ERROR STORE HEAD GLBL ERROR STORE HEAD USER ERROR STORE HEAD HISTORY the power supply switch on time to the power supply EEPROM An error occurred while storing the laser head global data to the laser head EEPR
68. EP return sleep status xIx Pulse Energy Setting CONT PENER lt n gt lt n gt lt n gt start pulse energy setting procedure X X X X X X X X CONT PENER 0 stop pulse energy setting procedure X X X X X X X X return the result of the pulse energy CONT PENER setting procedure X X XI X X X Laser Power Setting CONT POW lt n gt lt n gt lt n gt start power setting procedure X X X X X return the result of the power setting CONT POW procedure X X XI X X X X Command is not allowed a will be returned B 41 Explorer Actively Q Switched High Repetition Laser Systems B 42 Appendix C Operating Status Codes This appendix contains the following tables e Table C 1 System Status Byte on page C 1 e Table C 2 Operating Status and Error Bits on page C 2 e Table C 3 Fault Codes on page C 8 e Table C 4 Non Critical Fault Codes on page C 8 e Table C 5 Laser Emission Shutdown Conditions on page C 9 The query STB returns an 8 bit byte that yields the following information about the system status Table C 1 System Status Byte Bit Description Bit is activated 0 Laser emission if the diode laser is on or is in Standby mode 1 reserved N A 2 Command error if a serial command could not be executed correctly 3 System error if a system error is present e g temperature control configuration 4 reserved N A 5 Event summary if one or more events h
69. Explorer Actively Q Switched High Repetition Laser Systems User s Manual This laser product is intended to be sold to a manu facturer of OEM products for use as a component or replacement thereof in those products As such this product is exempt from performance standards of United States Code of Federal Regulations Title 21 Chapter 1 Food and Drug Administration Depart ment of Health and Human Services Subchapter J Parts 1040 10 a 1 or 2 G Spectra Physics A Newport Corporation Brand 3635 Peterson Way Santa Clara CA 95054 Part Number D 000 2140 Rev B March 2010 Preface This manual contains information for safely installing operating and ser vicing your Explorer actively Q switched high repetition laser system The system consists of an OEM Explorer laser head L Series power sup ply and customized operating software This manual covers several Explorer models with output wavelengths at either 355 nm or 532 nm These lasers use the same L Series power supply Chapter 1 Introduction contains a brief description of the Explorer laser systems Chapter 2 Laser Safety contains essential information for the safe use of these products The Explorer is a Class IV laser that emits laser radiation that can permanently damage eyes and skin This section contains informa tion about these hazards and offers suggestions on how to safeguard against them To minimize the risk of injury
70. HG Crystal Temperature THG Crystal Temperature Control THG Tjo cts TTHG 0 es Diode Hours 2 7 Pulse Count Mcts 311 Figure 6 9 Temperature Control Display When the L Win software is started the system enters Standard mode The set temperature and the measured temperature can be displayed but it is not possible to change the temperature setting while in this mode To change the temperature setting switch to Expert mode by selecting View GUI Mode from the L Win Main menu Figure 6 10 Do not change the temperatures of these components unless instructed to do so by an authorized Spectra Physics service representative 6 11 Explorer Actively Q Switched High Repetition Laser Systems 6 12 Tools re GUI Mode Power Control Temp Control Settings zE port S Spectra l KASRLI v Lou d L Win LASER cont Emission Laser 1D SPECTRA PHYSICS EXI 532 1000 100KP PV 008 ON P5 0272 B02 ENG V4 00 On V4 00 111 Figure 6 10 Selecting the GUI Mode Upon selecting GUI Mode a dialog box with a warning message appears Figure 6 11 I Switch_GUI_Mode vi rev 3 xi Expert Mode Do not activate Expert Mode if you are not absolutely sure that you know and understand what you are doing Changing settings in Expert Mode may result in serious changes of system performance or may even permanently damage the system ewe Lo Figure 6 11 Warning Entering Expert Mode
71. Heatsink Assembly Outline Drawing Figure 3 10 3 14 The Explorer Laser System Interlock Block Diagram e e ESD Er NE 12V protection User Interlock ot x EE 8 O33 S oO E5 S o 0 wi DE eo Software Interlock v v Keyswitch monitor Keyswitch Figure 3 11 Interlock Safety Block Diagram 3 15 Explorer Actively Q Switched High Repetition Laser Systems 3 16 Chapter 4 Controls Indicators and Connections This section describes the user controls indicators and connections of the Explorer laser head and power supply Connector types are also listed For a functional description of the ANALOG IN connector refer to Table 7 2 To control the system using either the L Win control software provided with the laser or serial commands and analog signals via the RS 232 and ANALOG IN connectors refer to the operating procedures described in Chapters 6 and 7 respectively The Explorer Laser Head Controls Indicators There are no controls on the Explorer laser head itself no adjustment is required The laser is controlled through the L Series power supply Note that there is no shutter on the Explorer laser head The laser head is designed for integration into a master OEM system that possesses the required safety features Emission indicator white turns on when an ON command is issued indicating that laser emission may be present The indicator remains on during las
72. IS PRODUCT IS MANUFACTURED UNDER ONE OR MORE OF THE FOLLOWING PATENTS U S PATENT NUMBERS S Spectra Physics 14532 STAHNSDORF Germany Serial Label Laser Head and Power Supply 6 4 653 056 4 872 177 5 080 706 5 504 762 5 651 020 5 999 544 6 890 474 4 656 635 4 894 839 5 127 068 5 561 547 5 745 519 6 185 235 RE 34 192 4 665 529 4 913 533 5 155 631 5 577 060 5 801 403 6 504 858 4 701 929 4 977 566 5 410 559 5 579 422 5 812 583 6 697 390 4 723 257 4 979 176 5 412 683 5 608 742 5 835 513 6 816 536 4 761 786 5 018 152 5 436 990 5 638 397 5 907 570 6 822 978 150 0123 Patent Label 8 Warranty Seal 9 Figure 2 6 Explorer CE Warning Labels WEEE Label 10 Explorer Actively Q Switched High Repetition Laser Systems Label Translations For safety the following translations are provided for non English speak ing personnel The number in parentheses in the first column corresponds to the label number listed on the previous page Table 2 2 Label Translations Label No French German Spanish Dutch Aperture Warning Label 2 Emission Indicator Label 3 Class 4 CE Warning Label 7 Ouverture Laser Exposition Dange reuse Un rayon nement laser visible et ou invisible est mis par cette ouverture Indicateur d mis sion Rayonnement laser visible et ou invisi ble Exp
73. J 532 nm Pulsduur 5 20 ns 2 8 Laser Safety Waste Electrical and Electronic Equipment WEEE Recycling Label To Our Customers in the European Union As the volume of electronics goods placed into commerce continues to grow the European Union is taking measures to regulate the production and disposal of waste from electrical and electronic equipment Toward that end the European Parliament has issued directives instructing Euro pean Union member states to adopt legislation concerning the reduction recovery re use and recycling of waste electrical and electronic equipment The directive that addresses the reduction recovery re use and recycling of waste electrical and electronic equipment is referred to as WEEE In accordance with this directive the accompanying product has been marked with the WEEE symbol See Label 10 in Figure 2 6 The main purpose of the symbol is to designate that at the end of its useful life the accompanying product should not be disposed of as normal munic ipal waste but should instead be transported to a collection facility that will ensure the proper recovery and recycling of the product s components The symbol also signifies that this product was placed on the market after 13 August 2005 At this time regulations for the disposal of waste electrical and electronic equipment vary within the member states of the European Union Please contact a Newport Spectra Physics representative for infor
74. L ERROR THG TEMPCONTROL ERROR DIODE1 PWM ERROR XTAL PWM ERROR DIODE1 PWM REBOOT ERROR XTALS PWM REBOOT STATus CONDition SYSTem DIODe1 ERROR CABLE ERROR CURRENT STATus CONDition SYSTem AnalogPORT WARNING MISSING EXT DIODE ON Reserved STATus CONDition SYSTem PowerSUPPLY ERROR PS PCB OVERTEMP ERROR DIGCONT PCB OVERTEMP STATus CONDition SYSTem COMPATibility HARDWARE MISMATCH reserved LASERHEAD SOFTWARE MISMATCH TEMPCONTROLLER A SOFTWARE MISMATCH TEMPCONTROLLER B SOFTWARE MISMATCH STATus CONDition SYSTem SOFTware EXC B 36 STATus CONDition CoMmanD o Ecss UNKNOWN_COMMAND o 1 COMMAND NOTALLOWED 1 2 Ecss wWAUD PARAMETER 2 3 Ec4e COMMAND_FAILED 3 ORd 4 EC46 5 EC46 6 7 ORd 15 8 9 10 m 12 13 EC58 14 15 J STATus CONDition SYSTem STB o Ecas L PARAMETERSET o LASER EMISSION 1 Ec4e E S LASERHEAD 1 Reserved 2 ECa4 30 gt TEMPERATURE CONTROLLER 2 CMD_ERROR 3 LASERDIODE 3 m gt SYSTEM ERROR 4 E3439 Gag r ANALOG INTERFACE
75. ND SYST SOFT 0 EXC An internal software exception Contact Spectra Physics service status was activated during the execution of the control ler software The laser remains fully operational Explorer Actively Q Switched High Repetition Laser Systems Table C 3 Fault Codes Code Description Code Description 0 No errors present 12 User interlock open 13 Keyswitch interlock open 23 Error diode laser temperature 24 Error SHG temperature 25 Error THG temperature 31 Error diode laser cable 32 Error diode laser current control 33 Power supply overtemperature 34 Laser head overtemperature 35 Error hardware mismatch 36 Error software mismatch 45 Laser head not connected 46 Laser head EEPROM malfunction 48 Error keyswitch reset required Turn the keyswitch OFF then back ON again 58 Bad configuration Power supply EEPROM error Table C 4 Non Critical Fault Codes Code Description 37 Warning undertemp heatsink 38 Warning overtemp power supply 39 Warning overtemp laser head These are notifications the laser is fully functional Table C 5 Laser Emission Shutdown Conditions Operating Status Codes Laser Emission Shutdown Condition Cause Indication Diode temperature error 23 Diode cable error 31 Diode current error 32 SHG xtal temperature error 24 THG xtal temperature error 25 Power supply over tempera ture 33 Laser head over tempera
76. NT TEMP This command sets the temperature set point for the fan control the setting has no effect if no fan is connected The command is rejected if the fan operation mode is set to Drive mode Unit degC Range f 18 0 degC s f lt 34 0 degC Examples gt HEAD FANCONT TEMP 33 5 lt CR gt lt lt CR gt lt LF gt gt HEAD FANCONT TEMP lt CR gt 33 5degC lt CR gt lt LF gt B 25 Explorer Actively Q Switched High Repetition Laser Systems IDN This command returns the product identification string Returned is a four comma separated field manufacturer model serial number laser head power supply firmware version laser head power supply If the laser head controller is not communicating with the power supply controller the laser head firmware version is replaced by 999 Examples Typical response SPECTRA PHYSICS EXPLORER 532 1000 100KP PL 0332 02 PS 0129 01 V4 00 44 V4 01 154 lt CR gt lt LF gt If the laser head communication fails SPECTRA PHYSICS EXPLORER 532 1000 100KP XXXXXXX PS 01 29 01 999V4 01 154 lt CR gt lt LF gt MODE RMT lt n gt MODE RMT This command enables n 1 or disables n 0 Computer remote mode Computer mode must be enabled to turn the laser on or off via the RS232 serial port Examples gt MODE RMT 1 lt CR gt Places the system in Computer mode and the laser is turned on by sending the ON command while the power s
77. OM An error occurred while storing the actual user parameter set to the laser head EEPROM An error occurred while storing the diode laser operating hours and the pulse counts to the laser head EEPROM Contact Spectra Physics service Contact Spectra Physics service Contact Spectra Physics service Check the cable connection between the power supply and laser head Contact Spectra Physics service Check the cable connection between the power supply and laser head Contact Spectra Physics service Check the cable connection between the power supply and laser head Contact Spectra Physics service System Condition HEAD Register Query STAT COND SYST HEAD ERROR COMMUNICATION ERROR CONFIGURATION ERROR PCB OVERTEMPERATURE ERROR QSWITCH RF POWE R ERROR_HEATSINK_ OVERTEMPERATURE ERROR_QSWITCH_TIMING HEATSINK_UNDERTEMPER ATURE An error occurred while com municating with the laser head An error occurred while retriev ing or updating the configura tion parameters of the laser head The laser turned off because the maximum printed circuit board temperature was exceeded The Q switch does not work properly The laser turned off because the maximum heatsink tem perature was exceeded Invalid Q switch timing param eters not lasing The heatsink temperature is below the minimum of 18 C typical The laser system remains fully operational Check the cable connection be
78. Q and allows the gain to rebuild to a high level This process is repeated at the frequency at which pulsed laser output is desired taking into consideration the characteristics of the laser The result is a concentra tion of the otherwise continuous laser beam into pulses of extremely high peak power Beam directed AOM on out of cavity Cavity Beam directed End to other cavity AOM off Mirror end mirror RF Drive Transducer Figure D 7 An Intracavity Acousto Optic Modulator Explorer Actively Q Switched High Repetition Laser Systems D 10 Notes Notes 1 Explorer Actively Q Switched High Repetition Laser Systems Notes 2 Notes Notes 3 Explorer Actively Q Switched High Repetition Laser Systems Notes 4 Notes Notes 5 Explorer Actively Q Switched High Repetition Laser Systems Notes 6 Report Form for Problems and Solutions We have provided this form to encourage you to tell us about any difficulties you have experienced in either using your Spectra Physics instrument or its manual problems that did n
79. RNING OVERTEMP POWERSUPPLY Issue error 33 ERROR POWERSUPPLY OVERTEMP Power unit returns to Clear error 33 supply lt 50 C ERROR POWERSUPPLY OVERTEMP User may exit Sleep mode All temperatures listed are typical values Operating with Commands and Signals Controlling the Laser Head Temperature The fan control has two modes drive mode and control mode In Drive mode a percentage value of the maximum voltage 13 V can be set In this mode the speed of the fan is independent of the laser head tem perature In Control mode the fan speed is dependent on the laser head temperature which can be set by the user To set the fan control mode enter the command HEAD FANCONT MODE lt n gt where drive mode is n 0 and Control mode isn 1 To read the current fan control mode enter query HEAD FANCONT MODE To set the fan speed enter the command HEAD FANCONT PVOLT lt f gt where lt f gt is an integer between 0 and 100 Example HEAD FANCONT PVOLT 50 To read the fan speed enter the query HEAD FANCONT PVOLT To set the laser head temperature in C enter the command HEAD FANCONT TEMP lt f gt where f is a decimal number 24 0 lt f lt 40 0 Example HEAD FANCONT TEMP 33 5 To read the laser head temperature in C enter the query READ HEAD BAS TEMP heatsink and fan only when the ambient temperature is about 10 lower Note gl the laser head temperature can be kept at a constant temperat
80. SW PRF MAX lt CR gt lt 60000Hz lt CR gt lt LF gt QSW PRF MIN This command reads the minimum pulse repetition frequency Unit Hz Table B 3 lists the minimum pulse repetition frequencies for the Explorer models Example gt QSW PRF MIN lt CR gt lt 20000Hz CR LF Pulse Counts and Operating Hours READ QSW CNTS This command reads the pulse counter in kilocounts or megacounts depending on Explorer model Unit kcnts or ments Examples gt READ QSW CNTS lt CR gt 34121kcnts lt CR gt lt LF gt The system has issued 34 121 000 pulses READ HEAD HOUR This command reads the laser head hours Laser head hours are incremented every 6 minutes 0 1 hour that power is supplied to the laser head Unit HrsHd Example gt READ HEAD HOUR lt CR gt lt 456 2HrsHd lt CR gt lt LF gt The laser head has been supplied with power for 456 2 hours READ PSUPPLY HOUR This command reads the power supply hours Power supply hours are incremented every 6 minutes 0 1 hour that power is supplied to the power supply Unit HrsPS Example gt READ PSUPPLY HOUR lt CR gt lt 478 7HrsPS lt CR gt lt LF gt The power supply has been supplied with power for 478 7 hours B 7 Explorer Actively Q Switched High Repetition Laser Systems READ DIOD1 HOUR This command reads the diode laser operating hours Diode laser operating hours are
81. TR etc in the Serial Port field instead of COMI COM2 etc Quit button exits the program All program settings serial port cal ibration settings are stored in the file L Win ini in the program directory Emission ON OFF button provides a switch to turn the laser on and off Click on it once to turn on the laser and the Emission indica tor turns green if no error is present Actual emission will occur after a 3 second safety delay Click on it again to turn the laser off immedi ately Explorer Actively Q Switched High Repetition Laser Systems Standby button sets the diode laser to standby current which is below the threshold for lasing and turns on the indicator it turns yel low Clicking this button again will return the laser to normal opera tion and the indicator will turn off it turns gray Control mode analog RS 232 control selects the control mode When set to analog the repetition rate and pump diode current are con trolled via the 26 pin ANALOG IN port In Program mode the controls for on off diode current and repetition rate are disabled When set to RS 232 those parameters are controlled by serial commands Control mode current set A control determines whether the pump current is set and displayed in Amperes or as a percentage of the maximum current setting which is the value returned by DIOD1 MAXC Pump Current fields provide a means to set the diode laser current and displa
82. To enter Expert mode press the Expert Mode button it turns red and con firm by clicking on OK The temperature controls are now activated To return to Standard mode select View GUI Mode again and press the Expert Mode button once more it turns black or restart the L Win software Depending on the Explorer model the THG crystal may not be available When this is the case the temperature control fields display 0 and are grayed out as shown in Figure 6 9 Before changing the diode laser temperature record the present values for operating current and temperature as well as the other laser parameters output power etc in the event that they need to be restored later To maintain the diode laser wavelength at its optimum value of 808 nm make small adjustments to the diode laser temperature in maximum increments of 0 5 C then wait a few seconds to see what effect the change has on pulse energy or average power before continuing Set the desired temperature of the pump diode using the Diode T set con trols The T Diode field displays the measured temperature in C If the ini tial operating parameters are lost restore the original temperature set points by activating the preset Factory 1 Operating Using the L Win Software Setting the SHG and THG Temperatures Note g Caution M The Explorer models that produce output at 532 nm do not contain a THG crystal only the SHG crystal temperature can be adjusted
83. VOLT CNTS This command modifies the reference voltage of the laser power ADC It may be used to re calibrate the displayed power to match the values read at the user s power meter Higher reference voltage counts result in lower power values Range lt n gt 200 1023 Unit cnts Example gt POW REFVOLT CNTS 456 lt CR gt lt lt CR gt lt LF gt gt POW REFVOLT CNTS lt CR gt lt 456cnts lt CR gt lt LF gt QSW PRF lt n gt QSW PRF This command sets the Q switch repetition frequency in Hertz 0 lt n lt maximum pulse repetition frequency i e the value returned by QSW PRF MAX n 0 disables internal pulse triggering and allows external triggering Unit Hz Table B 3 lists the PRF range for the Explorer models Examples gt QSW PRF 50000 lt CR gt Set the pulse frequency to 50000 Hz lt lt CR gt lt LF gt gt QSW PRF lt CR gt 50000Hz CR LF gt QSW PRF 0 lt CR gt Set the system to external triggering mode lt lt CR gt lt LF gt QSW PRF MAX This command reads the maximum pulse repetition frequency Unit Hz Table B 3 lists the maximum pulse repetition frequencies for the Explorer models B 28 Serial Commands and Queries Examples gt QSW PRF MAX lt CR gt lt 60000Hz lt CR gt lt LF gt QSW PRF MIN This command reads the minimum pulse repetition frequency Unit Hz Table B 3 lists the minimum pulse repetiti
84. WATCHDOG The software watchdog for Check the serial communication communication between the between your PC software and laser system and the host com the power supply puter is tripped Lengthen the watchdog alert time or disable the software watchdog 5 HARDWARE WATCHDOG The system has rebooted Contact Spectra Physics service because the hardware watch dog was activated System Operational Condition Register Query STAT COND OPER 0 STANDBY Standby mode is active was No action is required activated by software or by an external analog signal 1 BURST_BUSY Burst mode is activated and a No action is required burst is being carried out Check this bit before sending a new BURST command 2 NA 3 SLEEP MODE Sleep mode is activated the To re enable normal operation Q switch and TECs are use the MODE SLEEP 0 com switched off All serial com mand mands besides status que ries will be rejected 5 GATE The Gate signal is being No action is required applied to the analog port 6 EXT DIODE CURRENT External diode current control Apply a voltage of to pin 2 of the is activated pin 18 of the ANALOG port to adjust the analog port diode current 7 SYNC OVER BURST The SYNC pulse duration is No action is required extended to include the whole burst sequence 8 N A 9 NA 10 EXTERNAL TRIGGER External triggering mode is Apply a suitable trigger signal to activated pin 21 of the analog port FIRST PULSE SUPPRESSION FPS
85. X X X QSW PRF 0 set external trigger mode X X X X X X read last commanded pulse repetition QSW PRF frequency X X X X read actual pulse repetition frequency returns 0 Hz in external triggering READ QSW PRF mode X X X X return actual lower pulse repetition QSW PRF MIN frequency limit X X x return actual pulse repetition HAs eon al lls T2 T e Te thelist QSW PRF MAX frequency limit x x Diode Xtal Temperatures set the SHG crystal temperature in CONT SHG TEMP lt n gt DAC counts x X X X X X read last commanded SHG crystal CONT SHG TEMP temperature in DAC counts X x XIXIX read actual SHG crystal temperature READ SHG TEMP control loop in ADC counts X X XXIX set the THG crystal temperature in CONT THG TEMP n DAC counts X X X X X X X read last commanded THG crystal CONT THG TEMP temperature in DAC counts X X X X X X read actual THG crystal temperature difference control loop in ADC READ THG TEMP counts X X X X X X set the diode temperature in degrees DIOD1 TEMP f Celsius X XIXIX X read last commanded diode DIOD1 TEMP temperature X X XIX read actual diode temperature control READ DIOD1 TEMP loop in deg C x XIXIX Head Housing Temperature read actual laserhead housing READ HEAD BAS TEMP temperature x x x x read laserhead housing temperature HEAD BAS TEMP MAX limit in C unit degC x x B 39 Explorer Actively Q Switched High Repetition Laser Systems Laserhead Fan Control
86. ads Dh ee E aa e NG Jee en Veh ede See A 3 Power Control Tab Display 00000 cece ae A 3 Temperature Control Tab Display 0 000 eee A 4 Settings TaD Display neri EE E ER tae A op eect en o OP RR ed weet A 7 Menu Bar corse bsp Roe ped eee x ep ble E GU de AT bette gles aad des A 8 Tools MENU urhe d epu e Deren Exi pP RII QE ES Ia e d A 8 Terminal Display uini EX EPEISETIeUENFE VY Eu Sane MER SED MEME A 9 Status Bits VIeWOE s eir Pee ERECTO RIEN PERWAWIEEPEYEI ENS A 11 Set Output Power Energy 000 hh rrr A 12 Energy Power Measurement Calibration ssles ee A 13 FPS and Burst Control Display llilslleseee re A 14 Pulse Noise Display se tare uss ead prada E UMEN RPESERIMRNERY ESTEE EM A 16 System Settings Summary ze resar berks urt eioh eaa EE rn A 17 Appendix B Serial Commands and Queries B 1 Appendix C Operating Status Codes lllllllee C 1 Appendix D A Brief Review of Laser Theory lessen D 1 Emission and Absorption of Light 0 2 0 0 0c e m D 1 Population Inversion cerus Trens aa ren aa Ea a E aa e E A a hm hl D 2 Resonant Optical Cavity assess aaaea D 4 Nd as a Laser Medium 05 5186 6 fut eue eT LS ESL arranoa annanru itle DU del aa D 5 Diode Pumped Laser Design 00 e rr D 6 Harmonic Generation llsilelellelllll ehh rre D 7 Acousto Optic Modulation and Q Switching
87. als that convert the fundamental infrared light into the output beam The nonlinear crystals are temperature controlled to maintain the phase matching condi tion for efficient nonlinear optical conversion The laser head also contains the Q switch and its RF driver The diode laser pump source is typically operated at a derated power level in order to ensure extended lifetime In the context of this manual the diode laser module is sometimes referred to simply as the diode e g the diode current Introduction The L Series Power Supply System Control Patents The L Series power supply provides the low voltage high amperage drive current necessary to power the diode laser in the laser head A parallel interface on the power supply connects to the laser head to provide monitor and control functions The power supply requires a single 24 Vdc 4 A power source has an inte grated cooling fan and requires no water or external cooling connections The L Series power supply complies with the requirements of the Euro pean Union for safety noise and regulation of hazardous component mate rials See Chapter 2 for certification details As a component in a master system the Explorer system is designed to be controlled via serial commands and queries and or analog signals provided by the host system The host connects to the L Series through the power supply serial port The analog TTL control signals can either be used al
88. anel Connections on page 4 6 for details about using this option Attach a standard 9 pin M F serial cable between the RS 232 connector on the front of the power supply and the serial port on your computer Do NOT use a null modem cable Note the computer port number Refer to Table 4 1 on page 4 5 for a functional description of this con nector If analog signals are to be used to control the laser attach an analog control cable not provided between the analog port of your host con troller and the ANALOG IN connector on the power supply Refer to Table 7 2 for a functional description of each pin Note that pins 7 and 8 must be shorted together in order for the laser to operate A shorting jumper plug is provided for this purpose in case the ANALOG IN connector is not used These pins can used in a circuit to shut the laser off if a normally closed emergency switch is opened unex pectedly Pin 7 provides up to 100 mA at 12 Vdc Note also that pin 9 of this connector can be used to control an emission indicator Figure 7 4 on page 7 20 provides an example circuit No alignment is necessary for the Explorer laser head there are no controls to adjust nor optics to align Installation Initial Turn On Turn Off Using the L Win Software Danger Laser Radiation Eyewear m Required A Spectra Physics Explorer lasers are Class IV High Power Lasers whose beams are by definition safety and fire hazards Take precau
89. any unnecessary specular reflections or beams from escaping the laser operation area Set up a beam dump to capture the laser beam and prevent accidental exposure Figure 2 2 2 1 Explorer Actively Q Switched High Repetition Laser Systems VISIBLE AND OR INVISIBLE VISIBLE AND OR INVISIBLE LASER RADIATION LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT AVOID EYE OR SKIN EXPOSURE TO o SCATTERED RADIATION DIRECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT POWER WAVELENGTH S AND PULSE WIDTH DEPEND ON PUMP WIDTH DEPEND ON PUMP OPTIONS AND OPTIONS AND LASER CON POWER WAVELENGTH S AND PULSE FIGURATION LASER CONFIGURATION CLASS IV LASER PRODUCT SEE MANUAL 0451 8080 Figure 2 1 These standard safety warning labels are appropriate for use as entry warning signs EN 60825 1 2007 ANSI Z136 1 Section 4 7 Figure 2 2 Folded Metal Beam Target Caution Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure Danger Operating this laser without due regard for these precautions or in a U manner that does not comply with recommended procedures may be dangerous At all times during installation maintenance or service of the laser avoid unnecessary exposure to laser or collateral radiation that exceeds the accessible emission limits listed in Performance Standards for Laser Products United States Code
90. as well as specular beam reflections can cause severe an eye or skin damage The ultraviolet beam at 355 nm is invisible and is Eyewear g therefore especially dangerous Residual light at 1064 nm 808 nm and Required 532 nm wavelengths might also be present L Win is a LabView based graphical user interface GUI that provides a simple and direct method of controlling the Explorer laser as a stand alone system from a personal computer For example it can be used when install ing or servicing the laser system This chapter provides instructions for using L Win to control the most com monly used features of the laser For a complete description of each of the L Win displays refer to Appendix A L Win GUI Reference For instructions on operating the Explorer system using serial commands or analog signals see Chapter 7 Operating with Commands and Signals Note The procedures in this chapter assume that the Explorer laser has been S installed according to the instructions in Chapter 5 and that the laser has been installed with proper attention to heat removal the laser head power supply and computer have been properly con nected and that DC power is being supplied to the power supply the interlock relay and emission circuits if installed have been prop erly wired or the interlock jumper plug has been correctly installed the L Win software has been installed and appears to be functioning the
91. aser will remain off until the SHG and or THG temperatures have reached a stable operating condition Return to the Main display to resume laser emission 6 13 Explorer Actively Q Switched High Repetition Laser Systems Advanced Control of the Pulsed Output Burst Control The Explorer laser allows pulses to be grouped in packets that are sepa rated by periods of no laser output This is called Burst mode To set up Burst mode select FPS Burst Setup from the Tools menu as shown in Figure 6 12 Win vi rev 505 Terminal Status Bits Viewer Pulse Noise Measurement FPS Burst Setup Dump System Settings Set Output Power Energy Measurement Calibration L Wi Emission mai 478 Burst Mode and FPS Display Access Figure 6 12 Tools Menu The Burst mode display will appear as shown in Figure 6 13 BiBurst Mode cFG vi PIS x Laser Serial Port Pulse Energy Orta istPulse IB 1st Pulse pJ Other Pulses MN 14 24 Number of Pulses 1st Pulse per Burst FPS Delaytime us 14 Error in 27 1 ition Rate Hz Repetition Rate 50000 Current 4 Pump Current gr 9 5 10 15 20 25 30 35 40 45 50 55 Burst Loop Delay Pulses Status Burst done Figure 6 13 Burst Mode and FPS Display Note that the current and pulse repetition frequency can be changed using this display Use this display to set the laser to operate at the energy level and frequency desired for pulses that will com
92. at appears This will activate a display that can be used to type in serial com mands manually Operating with Commands and Signals Basic Serial Operating Control Note S Refer to Important Notes on Controlling Explorer Output on page 6 17 before making significant changes to the operation of the Explorer Serial vs Analog Control Before the laser can be operated using serial commands on off control must be transferred to the RS 232 serial port The following commands enable and disable any command signals applied to the ANALOG IN interface MODE RMT 1 puts the system in a mode where the system is con trolled only by commands sent via the serial port Any signals at the ANALOG IN interface are ignored MODE RMT 0 puts the system in analog mode where the laser system is the controlled by signals applied to the ANALOG IN interface the in addition to any serial commands Use the following query to determine if the laser is in Serial or Analog mode MODE RMT 1 the system is in Serial mode 0 the system is in Analog mode Turning the Laser On and Off The Watchdog Timer If the power switch and the keyswitch are both on and control has been transferred to remote operation turn the laser on and off by entering ON emission begins after a safety delay of about 3 seconds laser emission indicators on the laser head and power supply turn on immediately OFF causes laser emission to stop immediately and turns off
93. atic and coherent Radiant emission and absorption take place within the atomic or molecular structure of materials The contemporary model of atomic structure describes an electrically neutral system composed of a nucleus with one or more electrons bound to it Each electron occupies a distinct orbital that represents the probability of finding the electron at a given position relative to the nucleus Each orbital has a characteristic shape that is defined by the radial and angular dependence of that probability e g all s orbitals are spherically symmetrical and all p orbitals surround the x y and z axes of the nucleus in a double lobed configuration Figure D 1 The energy of an electron is determined by the orbital that it occupies and the over all energy of an atom its energy level depends on the distribution of its electrons throughout the available orbitals Each atom has an array of energy levels the level with the lowest possible energy is called the ground state and higher energy levels are called excited states If an atom is in its ground state it will stay there until it is excited by external forces Movement from one energy level to another a transition happens when the atom either absorbs or emits energy Upward transitions can be caused by collision with a free electron or an excited atom and transitions in both directions can occur as a result of interaction with a photon of light Con sider a transition from a lo
94. ature rises 5 C above the warning level Example gt HEAD BAS TEMP MAX CR lt 40degC lt CR gt lt LF gt B 24 Serial Commands and Queries HEAD FANCONT MODE lt n gt HEAD FANCONT MODE This command sets the operation mode of a connected fan either to Control mode where the base plate temperature is regulated to the adjusted set point refer to command HEAD FANCONT TEMP lt f gt or to Drive mode which provides a constant but adjustable voltage Range n n 1 control mode n 0 drive mode default Examples HEAD FANCONT MODE 1 lt CR gt lt lt CR gt lt LF gt gt HEAD FANCONT MODE lt CR gt lt 1 lt CR gt lt LF gt HEAD FANCONT PVOLT lt f gt HEAD FANCONT PVOLT This command sets the fan voltage in percent of the maximum voltage of 13 V if the fan operation mode is set to Drive mode The command is rejected if the fan operation mode is set to Control mode Unit Range lt f gt 0 100 Examples gt HEAD FANCONT PVOLT 50 0 lt CR gt Set the fan voltage to 50 6 5 Volt lt lt CR gt lt LF gt gt HEAD FANCONT PVOLT lt CR gt 50 lt CR gt lt LF gt HEAD FANCONT SPEED This command may be used to check proper operation of the fan control It returns the actual fan speed in counts range 200 1023 counts Example gt HEAD FANCONT SPEED lt CR gt 456cnts lt CR gt lt LF gt HEAD FANCONT TEMP lt f gt HEAD FANCO
95. ault list contains error 23 READ FAULT LIST Error LED is lit Fault list contains error 31 READ FAULT LIST Error LED is lit Fault list contains error 432 READ FAULT LIST Error LED is lit Fault list contains error 24 READ FAULT LIST Error LED is lit Fault list contains error 25 READ FAULT LIST Error LED is lit Fault list contains error 433 READ FAULT LIST Error LED is lit Fault list contains error 34 READ FAULT LIST Bit 44 of the event status byte is set STAT COND EVEN After start up bit 5 of the event status byte is set STAT COND EVEN Error LED is lit Fault list contains error 12 READ FAULT LIST Error LED is lit Fault list contains error 13 READ FAULT LIST Bit 0 of the analog interface sta tus byte is set STAT COND SYST APORT C 9 Explorer Actively Q Switched High Repetition Laser Systems C 10 Appendix D A Brief Review of Laser Theory Emission and Absorption of Light Laser is an acronym derived from Light Amplification by Stimulated Emission of Radiation Thermal radiators such as the sun emit light in all directions the individual photons having no definite relationship with one another But because the laser is an oscillating amplifier of light and because its output comprises photons that are identical in phase and direc tion it is unique among light sources Its output beam is singularly direc tional monochrom
96. ave taken place e g interlocks system boot software watchdog 6 reserved N A 7 Operational if one or more system conditions are enabled e g Standby external triggering mode Burst mode Explorer Actively Q Switched High Repetition Laser Systems Table C 2 Operating Status and Error Bits Bit a a Active Description Condition Action Required Serial Commands Register Query STAT COND CMD 0 UNKNOWN_CMD Unknown command Use allowed command from list 1 CMD_NOT_ALLOWED Command is not allowed e g Prepare system to accept the BURST when Burst mode is command not activated 2 INVALID PAR Command was sent using Make sure valid parameters are invalid parameter s used e g DIOD1 CURRENT 10 3 when the maximum diode current is set to 5 0 A 3 CMD FAILED A communication error with Check the cables to the laser the laser head or an internal head If the problem persists bus error occurred contact Spectra Physics ser vice System Condition Register Query STAT COND SYST 0 PAR SET There is a problem with the Retrieve detailed information by configuration set s commu querying the individual configu nication error invalid check ration set conditions sums 1 LASER HEAD There is a problem with the Retrieve detailed information to laser head communication pinpoint the cause of the prob error temperature etc lem 2 TEMP CONTROLLER Temperature controller failure Query temperature controll
97. booting return actual boot parameter set number store actual parameters as parameter set lt n gt load parameter set lt n gt x x x lt x lt x lt x gt lt CONFIG PARSET ACT Laser On Off Standby O MODE STBY B 40 return current parameter set number turn the laser diode on at the last commanded current N MODE STBY lt n gt place diode in STANDBY mode return computer standby mode x lt PERE bel Serial Commands and Queries First Pulse Suppression set the delay time of first pulse FPS DELAY lt n gt suppression to n secs X X X XX return delay time of first pulse suppression set number of pulses to be issued on next burst command enables disables burst mode return number of set pulses in burst mode X BURST perform burt ee e a enable disable SYNC signal over burst X X X return SYNC signal over burst setting X return analog port polarity CONFIG APORT POLAR configuration byte X X X CONFIG APORT POLAR n set analog port polarity configuration X X X X X STAT APORT SIGNAL return analog port pin status byte X X X Software Watchdog set the software watchdog alert time lt n gt 0 disables SW watchdog X x X X return the software watchdog alert time in seconds x X X Power Saving Mode MODE SLEEP n switch on off q switch TECs X xX X X X XIX MODE SLE
98. command sets the polarity of the analog interface lines refer to Table B 5 Range n 0 511 Individual bit position 1 line is high active rising edge Individual bit position 0 line is low active falling edge default Examples gt CONFIG APORT POLAR 96 lt CR gt Set polarity of pins EXTERNAL_DIODE_ON and STANDBY to high active lt lt CR gt lt LF gt gt CONFIG APORT POLAR CR 96 lt CR gt lt LF gt CONFIG PARSET ACT This command reads the active parameter set number refer to Table B 7 User Parameters Range lt n gt 1 4 n 1 user parameter set 1 n 2 user parameter set 2 n 3 factory settings 1 n 4 factory settings 2 Example gt CONFIG PARSET ACT lt CR gt lt 1 lt CR gt lt LF gt CONFIG PARSET BOOT lt n gt CONFIG PARSET BOOT This command designates the parameter set indicated by number to be loaded at next startup refer to Table B 7 User Parameters Range n 1 4 n 1 user parameter set 1 n 2 user parameter set 2 n 3 factory settings 1 n 4 factory settings 2 Examples gt CONFIG PARSET BOOT 1 lt CR gt lt lt CR gt lt LF gt gt CONFIG PARSET BOOT lt CR gt 1 lt CR gt lt LF gt CONFIG PARSET LOAD lt n gt This command loads parameter set lt n gt refer to Table B 7 User Parameters Range n 1 4 n 1 user parameter set 1 n 2 user parameter set 2 n 3 factory settings 1 n
99. ctra Physics field sales office service center or local distributor for shipping instructions or an on site service appointment You are responsible for one way shipment of the defective part or instru ment to Spectra Physics Equipment must be returned in the original shipping containers to secure instruments during shipment or the laser warranty is void If shipping boxes have been lost or destroyed new ones must be ordered We can return instruments only in Spectra Physics containers 8 9 Explorer Actively Q Switched High Repetition Laser Systems Service Centers 8 10 Belgium Telephone 0800 11 257 Fax 0800 11 302 China Newport Corporation Beijing Representative Office Room 2305 Building B Tri Tower No 66 Zhongguancun East Road Beijing 100080 P R China Telephone 86 10 6254 7746 Fax 86 10 6255 6373 France MICRO CONTROLE Spectra Physics S A 1 rue Jules Guesde Bat B ZI Bois de l Epine BP189 9106 Evry CEDEX France Telephone 33 1 60 9 1 68 68 Fax 33 1 60 9 1 68 69 E mail france newport fr com Germany and Export Countries Newport Spectra Physics GmbH Guerickeweg 7 D 64291 Darmstadt Germany Telephone 49 0 06151 708 0 Fax 49 0 0615 1 708 217 E mail verkauf newport de com Japan East Spectra Physics K K 4 6 1 Nakameguro Meguro ku Tokyo 153 0061 Japan Telephone 8 1 3 3794 5511 Fax 8 1 3 3794 5510 E mail spectra physics splasers co jp Japa
100. d has been issued by the software This L Win indicator turns on about 3 seconds before actual emission occurs e Pin9 of the ANALOG IN connector or the relay formed by pins 6 and 7 of the DCIN power connector can be used to control an external emission indicator Refer to Front Panel Connections on page 4 4 for more information The Explorer lasers are OEM systems that are designed to be integrated into a master system that itself complies with regulatory requirements As such it provides no internal shutter Diode Laser ON OFF Keyswitch The keyswitch on the front panel of the power supply Figure 2 4 provides power to the diode laser when it is turned on and it prevents unauthorized use of the laser when it is turned off and the key is removed Placing this switch in the ON position enables the laser to be turned on via serial com mands or analog signals DC Power ON OFF Switch Safety Interlocks The ON OFF power switch on the front panel of the power supply Figure 2 4 provides electrical power to the laser system when turned on External Interlock Pins 7 and 8 of the ANALOG IN connector must be shorted together for nor mal system operation They can be used in an interlock circuit to terminate laser emission when a normally closed safety switch wired to these pins is opened Such a switch can be attached to an access point such as an entry panel that might be opened unexpectedly See Chapter 7 for the circuit requireme
101. d alphabetically BURST This command performs a burst of the specified pulse count Note The command is executed only if the laser system is put into Computer REMOTE mode and the laser diode is ON Example of how to perform a burst 1 Set system in remote mode MODE RMT 1 lt CR gt 2 Select the desired pulse count per burst e g 100 BURST CNTS 100 lt CR gt 3 Switch laser on ON lt CR gt 4 Launch a burst BURST gt CR gt 5 Launch next burst BURST lt CR gt BURST CNTS lt n gt BURST CNTS This command sets the number of pulses issued at next BURST command using the currently active pulse repetition rate Unit cnts Range lt n gt O lt n lt 4000 n 0 disables Burst mode Examples gt BURST CNTS 100 lt CR gt Set burst count to 100 counts lt lt CR gt lt LF gt 2BURST CNTS CR 100cnts lt CR gt lt LF gt gt BURST CNTS 0 lt CR gt Disable Burst mode lt CR gt lt LF gt BURST SYNC lt n gt BURST SYNC This command sets synchronize over burst mode Range lt n gt n 1 span sync pulse over burst duration n 0 sync pulse will have standard duration Examples gt BURST SYNC 1 lt CR gt Span sync pulse over burst duration lt lt CR gt lt LF gt 2BURST SYNC CR 1 lt CR gt lt LF gt Explorer Actively Q Switched High Repetition Laser Systems CONFIG APORT POLAR lt n gt CONFIG APORT POLAR This
102. damage holes in the containers crushing etc insist that a representative of the carrier be present when you unpack the contents Keep the shipping container If you file a damage claim you may need it to demonstrate that the damage occurred as a result of shipping If you need to return the system for service at a later date the specially designed con tainer assures adequate protection Equipment must be returned in the designated Spectra Physics shipping container or the laser warranty is void System Components Accessory Kit Two components comprise an Explorer laser system e Explorer laser head e L Series power supply If ordered an optional custom heatsink with fan and or a wall plug auto ranging ac dc converter will also be included with the shipment Verify that all components are present The laser system is shipped in a single con tainer The power supply weighs approximately 0 9 kg 21b The laser head weighs approximately 1 2 kg 2 6 Ib Both can be handled easily by one person Included with the laser system is this manual a packing slip listing all the parts shipped and an accessory kit containing the following items Spectra Physics part numbers are given in parentheses e l laser head cable 1 15 pin PS L08 XX Headl e l laser head cable 2 26 pin PS L08 XX Head2 e 1 jumper plug for the ANALOG IN connector e 2 keys for the L Series power supply e 1 heat conducting foil for mounting
103. e 0 emm 7 8 Laser System Settings 0 0 ccc teens 7 8 Configuring Analog Control llssssssssseee emm rr 7 8 Component Temperature Adjustment 0 00 ren 7 9 Setting the Diode Pump Laser Temperature 0 0000 cece tte 7 9 Setting the SHG and THG Crystal Temperatures 0 00000 cece eee 7 9 System Temperature Management 000 cece rns 7 10 Controlling the Laser Head Temperature 0 00 tt eee 7 11 Control of the Pulsed Output 0 0 0 0 cette 7 12 Burst Control ez mat r astia ha a de EAS SW cole Rot pe Be edes rd 7 12 EPS ObperatlOn iaee nan expe acd PGi AAG uen IUS bbe een Go eee eG ead PORE RUE 7 13 Automatic Pulse Energy or Power Adjustment llle eee 7 13 The Analog Interface cn kA Sate lu x eere b ete edo uv Ue Red n 7 15 Basic Analog Operation 0 000 c ccc mmm 7 18 Turning the Laser On and Off 00 ccc hr 7 18 Adjusting the Pump Diode Current Using Analog Signals lille leeren 7 19 External Q Switch Triggering 2 lliiislelsesseele tees 7 19 Setting the Laser to Standby 0 0 c ccna 7 19 Monitoring Laser Status 0 0 c cnt eee eee 7 20 Using the Indicator Outputs 2 0 0 saaana aa 7 20 Pulse Energy Monitor Average Power Monitor liliis 7 20 External Syne aa xem er eae Ea ae keg be P des 7 21 OptoSynG oeste sag ate ert Ses ee Re ed ay qiie e tal Sh ae ee on 7 21 Explorer Actively
104. e conditions favorable to light amplification The follow ing paragraphs describe these conditions Population Inversion D 2 The net absorption at a given frequency is the difference between the rates of emission and absorption at that frequency It can be shown that the rate of excitation from E to E is proportional to both the number of atoms in the lower level N and the transition probability Similarly the rate of stimulated emission is proportional to the population of the upper level N3 and the transition probability Moreover the transition probability depends on the flux of the incident wave and a characteristic of the transition called its cross section The absorption coefficient depends only on the differ ence between the populations involved N and N and the flux of the inci dent wave A Brief Review of Laser Theory When a material is at thermal equilibrium there exists a Boltzmann distri bution of its atoms over the array of available energy levels with most atoms in the ground state Since the rate of absorption of all frequencies exceeds that of emission the absorption coefficient at any frequency is positive If enough light of frequency v is supplied the populations can be shifted until N N Under these conditions the rates of absorption and stimulated emission are equal and the absorption coefficient at frequency vis zero If the transition scheme is limited to two energy levels it is impossible t
105. e diode laser current as a percentage of the maximum current limit f current in percent of value returned by DIOD1 MAXC Unit 961 Examples gt PCUR 34 6 lt CR gt lt lt CR gt lt LF gt gt PCUR lt CR gt 34 6 1 lt CR gt lt LF gt PENER CALF This command reads the calibration factor which is used to convert the pulse energy ADC counts 0 1023 to the displayed microjoule values The calibration factor is set at the factory Unit uJ Example gt PENER CALF lt CR gt 0 5234yuJ 1 CR LF PENER REFVOLT CNTS n PENER REFVOLT CNTS This command modifies the reference voltage of the pulse energy ADC It may be used to re calibrate the displayed pulse energy to match the values read at the user s energy meter Higher reference voltage counts result in lower pulse energy values Range n 200 1023 Unit cnts Examples gt PENER REFVOLT CNTS 456 lt CR gt lt lt CR gt lt LF gt B 27 Explorer Actively Q Switched High Repetition Laser Systems gt PENER REFVOLT CNTS lt CR gt lt 456cnts lt CR gt lt LF gt POW CALF This command reads the calibration factor which is used to convert the laser power ADC counts 0 1023 to the displayed milliwatt values The calibration factor is set at the factory Unit mW cnt Example gt POW CALF lt CR gt lt 0 044mW cnt lt CR gt lt LF gt POW REFVOLT CNTS lt n gt POW REF
106. e is much greater than the rest This first pulse anomaly can be avoided by using the Explorer s First Pulse Suppression FPS feature FPS allows the user to adjust the first pulse in a train so that it has approximately the same energy as the rest of the pulses FPS reduces the pump energy for the first pulse by reducing the time allowed for light to circulate within the laser resonator before the first pulse is emitted thereby reducing the disproportionally large amount of energy initially absorbed by the laser crystal FPS implementation requires the monitoring and measurement of the energy of individual pulses This capability is built into the lower repetition rate range versions of the Explorer laser system The higher repetition rate models require the user to provide an external measurement of the pulse energy in order to implement FPS Refer to Advanced Control of the Pulsed Output on page 6 14 and Con trol of the Pulsed Output on page 7 12 for examples of how FPS can be implemented First pulse energy r w o First Pulse Suppression w o FPS First pulse energy ll with EPS with First Pulse Suppression Pulse Energy 1 2 3 4 5 6 7 8 9 10 Pulse Number Figure 3 7 The First Pulse Effect at High Repetition Rates 1 Only EXPL xxx yyy E models Explorer Actively Q Switched High Repetition Laser Systems Specifications Table 3 1 Explorer Performance Specifications Environmental s
107. easurement Calibration opens a new window where the output pulse power high rep rate systems or average energy low rep rate systems that is displayed on the Main menu can be calibrated against an external source Refer to Energy Power Measurement Calibra tion on page A 13 Sy Terminal 1 vi L Win Terminal Communication Serial Port Wo f mue C a Command String ne head bas temp System Answer 33 SdegCirin Figure A 11 Terminal Display A 9 Explorer Actively Q Switched High Repetition Laser Systems A 10 The Terminal display can be used to communicate with the laser system via serial commands Refer to Appendix B for a complete list of serial commands queries and responses The termination characters r carriage return and n new line shown in the System Answer box correspond to lt CR gt and lt LF gt respectively as described in Serial Communication on page 7 2 The L Win Main display remains active while the Terminal window is active and it is continually updated to reflect any new settings or condi tions that result from serial commands in the Terminal window display Serial Port field provides a pull down menu for manually selecting the serial port of the control computer to which the power supply is connected init port button initializes communication with the power supply The indicator is on red while the link is active QUIT button exi
108. ed High Repetition Laser Systems Burst Mode BURST CNTS lt n gt BURST CNTS This command sets the number of pulses issued at next BURST command using the currently active pulse repetition rate Unit cnts Range lt n gt O lt n lt 4000 n 0 disables Burst mode Examples gt BURST CNTS 100 lt CR gt lt CR gt lt LF gt Set burst count to 100 counts gt BURST CNTS lt CR gt 100cnts lt CR gt lt LF gt gt BURST CNTS 0 lt CR gt lt CR gt lt LF gt Burst mode is disabled BURST SYNC lt n gt BURST SYNC This command sets synchronize over burst mode Range lt n gt n 1 span sync pulse over burst duration n 0 sync pulse will have standard duration Examples gt BURST SYNC 1 lt CR gt gt BURST SYNC 1 lt CR gt Span sync pulse over burst duration gt BURST SYNC lt CR gt lt 1 lt CR gt lt LF gt BURST This command performs a burst of the specified pulse count Note The command is executed only if the laser system is put into Computer REMOTE mode and the laser diode is ON Example of how to perform a burst 1 Set system in remote mode MODE RMT 1 lt CR gt 2 Select the desired pulse count per burst e g 100 BURST CNTS 100 CR 3 Switch laser on ON lt CR gt 4 Launch a burst BURST gt CR gt 5 Launch next burst BURST lt CR gt B 18 Serial Commands and Queries Table B 2 Serial Commands and Queries liste
109. ed which is typical of any pulsed laser The duration of pulses is commonly measured at their full width at half maxi mum or FWHM The graphs in Figure 3 3 show the typical results of these effects T 2 S E gt gt oO c LL o p 2 a 1 0 2 0 3 0 4 0 5 0 6 0 7 0 Diode Laser Current A o 2 is fo E S z fb 2 2 a 1 0 2 0 3 0 4 0 5 0 6 0 7 0 Diode Laser Current A Figure 3 3 Variation of Energy and Pulse Width vs Current At a given diode laser pump current the individual pulse energy itself will decrease as the repetition rate is increased as shown in Figure 3 4 The lower the diode laser pump current i e the lower the average output power the less pronounced this effect will be Pulse width broadens in a strictly linear manner when the pulse repetition rate is increased The Explorer Laser System EXPL 532 2W P EXPL 355 300 P Pulse Energy uJ 0 50 100 150 Pulse Repetition Rate KHz Figure 3 4 Pulse Energy vs Pulse Repetition Rate EXPL 532 2W P EXPL 355 300 P Pulse Width ns Pulse Repetition Frequency kHz Figure 3 5 Pulse Width vs Pulse Repetition Rate Explorer Actively Q Switched High Repetition Laser Systems Control Features OptoSync Output Burst Mode 3 8 The OptoSync output provides a TTL level signal that is in high coinci dence with the p
110. ee Figure 7 3 for an example of a circuit that can be used to control this function 7 19 Explorer Actively Q Switched High Repetition Laser Systems Monitoring Laser Status Using the Indicator Outputs Figure 7 4 shows an example of a circuit that can be used to turn one of three Explorer analog interface indicators on and off This circuit works for the indicators available on pin 9 EMISSION indicator pin 11 READY indi cator and pin 13 INTERLOCK active indicator When the condition corre sponding to the pin output is active the internal transistor connected to the pin will turn on The LED shown in the figure will then turn on indicating that the laser condition is active e g pin 9 will indicate that the Explorer is emitting optical pulses 5 V Pin 9 Emission Pin 11 Ready L Pin 13 2 Interlock 9 c gt x xX 74ACTxx E o Pin n a AA N o0 0 dH AA o 5 V BAV99 1000 18 Pin 24 Gnd a o o o Gnd co L Series External Circuit Figure 7 4 Laser Indicator Circuit Example Note that pin 24 is the reference ground pin on the ANALOG IN connector and should be used with pins 9 11 and 13 Pulse Energy Monitor Average Power Monitor 7 20 Figure 7 5 shows the circuit for the output signal at Pin 1 of the ANALOG IN port Pin 1 provides a calibrated feedback signal from the power detector that is integrated into the laser head see Table B 3 The resolutio
111. ee eae 8 5 Figure 8 3 Loosen the bottom retaining screw 0 0 ce eae 8 5 Figure 8 4 Remove the window assembly 0 c cece eee rh 8 6 Figure 8 5 Replace the window assembly 00 0 cece teeta 8 6 Figure A 1 L Win Main Display 0 0 00 RII Ir A 1 Figure A 2 Status Panel Pulse Energy 0 000 cece eee tte A 2 Figure A 3 Status Panel Average Power 0000 cece n A 2 Figure A 4 Power Control Tab Display 0 000 cents A 3 Figure A 5 Temperature Control Tab Display 0 0000 0 cece tees A 4 Figure A 6 Selecting the GUI Mode 000 ccc rers A 5 Figure A 7 Warning Entering Expert Mode 0 0 0 eee eee eee A 6 Figure A 8 Settings Tab Display sselseeseeeee hrs A 7 Figure A 9 Tools Menu Average Power 0 00 eee rr A 8 Figure A 10 Tools Menu Pulse Energy lsseleeeee tee eae A 8 Figure A 11 Terminal Display sirens adede eeu a a a E e RR m A 9 Figure A 12 Status and Error Display 00 0c eect ee A 11 Figure A 13 Set Output Energy Display 0 0000 cette A 12 Figure A 14 Energy Power Measurement Calibration Display 000000 ies A 13 Figure A 15 FPS and Burst Control Display 00 0c ee A 14 Figure A 16 Pulse Noise Display cosis cs ya perean ira EE EERE eee m ERE A 16 Figure A 17 System Settings Summary sslsllseeleelee ren A 17 Figure D 1 Electrons occupy distinct
112. energy can be reduced so that all pulses in a sequence have approximately the same energy See First Pulse Suppression on page 3 9 for a further description of the first pulse effect The first pulse suppression feature can be used independently from burst mode e g when using external gating via TTL signals on the ANALOG IN port In this case the burst mode setup tool can be used to setup the correct FPS timing Useful operating modes of the Explorer laser using FPS are FPS with Gat ing and FPS with Burst mode Refer to Control of the Pulsed Output on page 7 12 for more information For convenience both the current and the pulse repetition frequency can be changed using the FPS and Burst mode display Figure 6 14 FPS with Models with an Internal Pulse Monitor To use FPS set the FPS Delay Time parameter in microseconds so that the first pulse has approximately the same energy as subsequent pulses in a Only EXPL xx yyy E models 6 15 Explorer Actively Q Switched High Repetition Laser Systems burst The recommended starting value of the FPS delay time is the inverse of the applied pulse repetition frequency For example if the pulse repeti tion frequency is 50 kHz the recommended FPS starting value is 20 us Iterate the FPS delay time around this starting value to minimize the differ ence between the first pulse energy and the energy of subsequent pulses in the chain Burst Mode cFG
113. ent WEEE Recycling Label 0 2 9 CE Declaration of Conformity 0 0 0 00 ete teen eee 2 10 Sources for Additional Information 00 teens 2 11 Laser Safety Standards 0 0 a eee eee 2 11 Equipment and Training xm ket en dE dme dO gre os Ease o a nee eis 2 12 vii Explorer Actively Q Switched High Repetition Laser Systems Chapter 3 The Explorer Laser System 000 cece eee eee eee 3 1 The Explorer Laser Head orris ecarri eaae a A tet eee 3 1 OVEIWIEW rion tu Bua hehe ee cee ane Mapas coe bo Rare od a Reread Atay aces acide 3 1 OpticaliDesign x x3 or ML e cm hate a Ltd a ir c ed MUNG Eel AD LE AE 3 1 Frequency Doubling and Tripling 0 cece RII 3 2 Pulse Energy and Average Power Monitors 0 0c ete 3 3 Replaceable Output Window sssseeseesel rs 3 3 Laser Head Thermal Management sese ren 3 3 The L Series Power Supply ssesslseeeeeeeellll hh 3 4 SYStEM Controls ark he erbe due E A ere NE Sce REN REDE A DR FUR olea e ai ela 3 4 System Control Hardware 2 0 00 cece eee 3 4 Laser Performance 000 e a A ee eee eee 3 6 Control Features oiri sare Haein aa ete Mee eee Gee bi Malta A es e s 3 8 OptoSync Output oi uet cou Sach ereed wag be EA ee Mi ed ache bate dy de dye ens 3 8 Burst Mode isses eec REGULA E EAS sce Em ee ar P eae he qr Ee 3 8 First Pulse Suppression iiississesseeleeeeel tees 3
114. ent display shows the average power or pulse energy averaged over 100 pulses as internally measured using the current calibration factor stored in the laser head Noise display displays the pulse energy noise in a window 1 sigma value Refer to Pulse Noise Display on page A 16 This display is only active on models with single pulse energy measurement EXPL xxx yyy E lasers ADC Reference voltage Old Value display shows the current reference voltage calibra tion value in counts New Value display shows the new reference voltage calibration that was calculated after the externally measured power pulse energy was entered Calibration Factor fixed display shows the internal calibra tion factor This is variable is non changeable for certain systems and is for Spectra Physics use only A 13 Explorer Actively Q Switched High Repetition Laser Systems Set Calibration button allows the operator to activate the new ref erence voltage calibration the calculated New Value After pressing this button the Old Value equals the New Value and the value displayed as Internal Measurement should be the same as that shown in External Measurement Note The new calibration can be permanently stored in one of the user defin able parameter sets User Setting 1 or 2 The power energy calibration is a global parameter that is the same for all parameter sets Quit button quits the application and closes
115. eplacing either the entire power supply or laser head Unauthorized repair will void the warranty Spectra Physics offers Service Training Programs to train personnel in the diagnosis of problems and repair of the power supply These training programs are tailored to suit the needs of the customer and can be conducted on site or at our factory For more information or to schedule a training program contact your sales rep resentative For information concerning the repair of your unit by Spectra Physics please call your local service representative A list of world wide service sites is included at the end of this chapter Before calling however note the serial numbers of the laser and power supply The following is a list of parts that can be purchased to replace broken worn out or misplaced components The replacement of internal Explorer system components must only be performed by personnel trained in these specific procedures by Spectra Physics Do not order a field replaceable unit or attempt to replace an internal system component without first receiving proper training Table 8 1 Field Replaceable Units Description Part Number Output window customer exchangeable 355 nm systems 532 nm systems Cable Laser head cable 1 Cable Laser head cable 2 EXPL 355 OW EXPL 532 OW 15 pin PS LO8 XX HEAD1 26 pin PS L08 XX HEAD2 Explorer 355 nm DPSS Laser Head 20 kHz 60 kHz 20 kHz 150 kHz ICT
116. er crystals and or diode laser conditions 3 J LASER DIODE There is a problem with the Query diode laser conditions diode laser e g cable cur rent control 4 ANALOG INTERFACE There is a problem with the Query analog port conditions analog port pins 5 POWER SUPPLY There is a problem with the Query power supply conditions power supply 14 HARDWARE SOFTWARE The updated software does Contact Spectra Physics service MISMATCH not match the hardware found 15 SW EXCEPTION An internal software exception Contact Spectra Physics service status was activated during the execution of the control ler software The laser remains fully operational System Events Condition Register Query STAT COND EVEN 0 USER INTERLOCK The user interlock is activated Check the cause of the activated KEY INTERLOCK The keyswitch is OFF interlock Reset the keyswitch if Auto On mode is disabled Turn keyswitch to ON position C 2 Table C 2 Operating Status and Error Bits Continued Operating Status Codes Bit cor n Active Description Condition Action Required 2 KEY LOCK A keyswitch reset is necessary Reset the keyswitch turn the this condition can only occur key to the OFF position and if Auto On mode is disabled then to the ON position again 3 SYSTEM BOOT Notification the laser system No action is required by the user has been booted the bit is cleared automatically after a reading 4 SOFTWARE
117. er emission and turns off when current to the diode laser is termi nated Emission Indicator white Output Beam Figure 4 1 Explorer Laser Head Emission Indicator 4 1 Explorer Actively Q Switched High Repetition Laser Systems Connections 4 2 Emission Indicator o o o o o o o o oooooooo ooooooooo 90990000029 o o o o o o o Laser Head Laser Head Cable 1 Cable 2 Connector Connector Figure 4 2 Explorer Laser Head Rear Panel Connections Laser Head Cable 1 connector 15 pin D sub male provides connec tion for the control cable from the LASERHEAD 1 connector on the back of the L Series power supply It provides the diode laser drive current and the current for the thermoelectric coolers TEC that cool the optical compo nents in the laser head Laser Head Cable 2 connector 26 pin D sub HD male provides con nection for the control cable from the LASERHEAD 2 connector on the back of the L Series power supply which provides monitoring and control func tions for the laser head Controls Indicators and Connections The L Series Power Supply ANALOG Input Connector RS 232 Input Connector Diode Laser LED ON OFF indicators Keyswitch O POWER EMISSION 1 O ss DC Power SHBRROR ON OFF Switch o9 o9 DC Power Input Connector Figure 4 3 Power Supply Front Panel Front Panel Controls DC power ON OFF switch provides DC power to the las
118. er head LASERHEAD 2 connector 26 pin D sub HD female provides attach ment for a control cable that connects to the laser head Laser Head Cable 2 male 26 pin connector This connector provides monitoring and control signals to and from the laser head Chapter 5 Installation Thermal Management Warning m Proper heat conduction is essential to allowing the Explorer laser to per form according to specifications Determine the heat removal capacity of your heatsink mounting before installing the laser head At a normal operating temperature of 25 C the laser head produces about 30 W of waste heat At the maximum specified operating temperature of 35 C the heat load that must be removed is about 40 W The laser head should be mounted on a heatsink capable of maintaining its baseplate tem perature below 40 C but greater than 18 C Cooler ambient temperatures makes it easier to dissipate waste heat through the baseplate Refer to Figure 5 1 for the thermal impedance required for the heatsink The heatsink surface must be flat to 0 050 mm or better if no heat conducting material is used such as the included silicone thermal pad Never use thermal grease when mounting the laser head on the heatsink Doing so will contaminate the laser package and the output window 1 0 Heatsink Thermal Impedance for Maximum 0 8 L Laser Head Baseplate Temperature of 40 C EE SP o6 b ea S 5 EG 04r x o Wo zt
119. er head when set to the ON position When the laser is installed in its final configuration leave this switch in the ON position in order to control the laser remotely When this switch is turned on the red ERROR LED turns on and remains on during the power supply warm up sequence which takes a few minutes from a cold start While the ERROR LED is on the Explorer laser cannot produce laser light This safety feature prevents possible damage to the internal optical compo nents that might result if intense intracavity laser light is produced before the laser components have achieved proper operating temperature Once the ERROR LED turns off the laser can be turned on Diode laser ON OFF keyswitch provides power to the diode laser in the laser head when it is set to the ON position For safety when the system is not installed in the master OEM system and or is not in use turn the key switch to OFF and remove the key to prevent unauthorized use of the laser The function of this switch depends upon the software mode setting Plac ing this switch in the ON position allows the laser to be turned on via serial commands or analog signals When the laser is installed in its final config uration leave this switch in the ON position in order to control the laser remotely Explorer Actively Q Switched High Repetition Laser Systems Front Panel Indicators POWER indicator yellow turns on when the power switch is turned on indicating
120. er if the screws at least the bottom screw remain in place 8 5 Explorer Actively Q Switched High Repetition Laser Systems 3 The window assembly can now be removed using tweezers Figure 8 4 Alternatively the window assembly can be removed using gloved fingers by handling the rim mount remember never touch the win dow itself NN Figure 8 4 Remove the window assembly 4 Inspect the window surface and clean it if necessary following stand ard practice for ultraviolet optics feel free to consult Spectra Physics regarding these procedures If necessary replace the window assem bly with a new assembly 5 Carefully place the window in the holder and while holding the win dow in position tighten the bottom retaining screw until the screw head gently touches the window mount Figure 8 5 Make sure that the screw head fits into the clearance in the mount Figure 8 5 Replace the window assembly 6 Tighten the top retaining screw until the screw head touches the mount Carefully tighten both screws using the minimum torque needed to secure the assembly 8 6 Maintenance and Service Service Training Programs Replacement Parts Warning n The Explorer diode pumped Q switched laser is designed for hands off operation This laser system does not require daily alignment nor routine cleaning of cavity optics With the exception of the laser output window servicing components is generally limited to r
121. erature for the SHG or THG crystal in counts Example CONT SHG TEMP 1650 System Temperature Management 7 10 The Explorer system continuously monitors component temperatures dur ing operation If a laser head or power supply over temperature condition is detected the system will perform a safety shut down by entering Sleep mode in order to prevent any damage Before the shut down condition is reached however warning codes are issued and the system continues to operate normally The temperature conditions of the laser system may be checked using serial commands or the Status Viewer display of L Win The laser head temperature can be checked with the READ HEAD BAS TEMP query Table 7 1 System Response to Over Temperature Conditions Component Temperature Action Laser head lt 18 C Issue error 37 WARNING UNDERTEMP HEATSINK Laser remains fully operational Laser head gt 35 C Issue error 39 WARNING OVERTEMP HEATSINK Laser remains fully operational Laser head gt 40 C Safety shutdown Sleep mode is activated Clear error 38 WARNING OVERTEMP LASERHEAD Issue error 34 ERROR LASER HEAD OVERTEMP Laser head unit returns to Clear error 34 lt 50 C ERROR LASER HEAD OVERTEMP User may exit Sleep mode MODE SLEEP 0 Power gt 50 C Issue error 38 supply WARNING OVERTEMP POWERSUPPLY Laser remains fully operational Power gt 55 C Safety shutdown Sleep mode is activated supply Clear error 38 WA
122. es design ensures reliable operation even in harsh environments The L Series power supply has been certified to comply with the requirements of the RoHS Directive the Restriction of Hazardous Substances of the European Union Spectra Physics offers an optional wall plug auto ranging ac dc converter to provide 24 V power the Explorer laser Contact your Spectra Physics representative for more information As a component in a master system the Explorer is controlled using either the serial command language or analog signals described in Chapter 7 or a combination of both The ports for the serial and analog interfaces are located on the power supply The most common methods of operating the laser are described in Chapters 6 and 7 The Explorer can also be operated as a stand alone system using the custom L Win software provided with the laser System Control Hardware 3 4 Note Figure 3 2 is a schematic of the main logic components in the laser head and L Series power supply The microprocessor inside the L Series power supply controls the power supply itself and communications with the laser head The laser head has its own microprocessor for controlling laser head functions such as maintaining the harmonic crystal temperature control ling diode laser current and receiving and storing operating parameters The versatility of the L Series results in part from the use of a CPLD Com plex Programmable Logic Device By setting operati
123. eset User 1 X Store Settings in Power Supply Preset User 1 xi Boot with Preset User 1 E Figure 6 6 Settings Tab Calibration Factor The Pulse energy calibration factor or Average Power Calibration Factor avail able under the Settings tab enables a calibration factor for the internal pulse energy monitor readings A value of 1 shows the unchanged pulse energy values as reported by the Explorer laser This factor can be changed to correct the displayed values to correspond with an external energy power meter This calibration only adjusts the L Win display readings It does not calibrate the values reported by the pulse energy monitor itself To permanently change the internal calibration of the power pulse energy monitor see Appendix A Energy Power Measure ment Calibration 6 8 Operating Using the L Win Software Tracking Operating Hours Pulse Counter Diode Pump Laser Hours of Operation Figure 6 7 Tracking Operating Hours The Diode Hours field shown on the Temp Control display tracks the total number of hours the diode pump laser has been operated This information is also useful for monitoring the lifetime of the nonlinear crystals in the laser head The Pulse Count Mcts field displays the total number of pulses in millions of pulses Mcts that the laser has emitted during its lifetime The pulse counter is set to O prior to shipment Explorer Actively Q S
124. et to Drive mode Unit degC Range lt f gt 18 0 degC lt f x 34 0 degC Examples gt HEAD FANCONT TEMP 33 5 lt CR gt lt lt CR gt lt LF gt gt HEAD FANCONT TEMP lt CR gt 33 5degC lt CR gt lt LF gt B 16 Serial Commands and Queries HEAD FANCONT PVOLT lt f gt HEAD FANCONT PVOLT This command sets the fan voltage in percent of the maximum voltage of 13 V if the fan operation mode is set to Drive mode The command is rejected if the fan operation mode is set to Control mode Unit Range lt f gt 0 100 96 Examples gt HEAD FANCONT PVOLT 50 0 lt CR gt Set the fan voltage to 50 6 5 Volt lt lt CR gt lt LF gt gt HEAD FANCONT PVOLT lt CR gt 50 lt CR gt lt LF gt HEAD FANCONT SPEED This command may be used to check to proper operation of the fan control It returns the actual fan speed in counts range 200 1023 counts Example gt HEAD FANCONT SPEED lt CR gt 456cnts lt CR gt lt LF gt First Pulse Suppression FPS FPS DELAY lt n gt FPS DELAY This command sets the FPS delay time to lt n gt usec Unit usec Range lt n gt Osns 2000 n 0 disables FPS Examples gt FPS DELAY 678 lt CR gt Set FPS delay is 678 usec lt lt CR gt lt LF gt gt FPS DELAY lt CR gt lt 678usec lt CR gt lt LF gt gt FPS DELAY 0 lt CR gt Disable FPS lt CR gt lt LF gt Explorer Actively Q Switch
125. ets of operating parameters Two sets can be saved by the user two are read only factory pre sets The parameters are loaded automatically at boot up and can also be activated after operation has begun A user set comprises the parameters listed in Table B 7 In addition to parameters that are specific for one of the four parameter sets a set of glo bal parameters exists see Table B 8 These are also stored each time a specific parameter set is stored To save the current operating parameters enter the following command CONFIG PARSET STOR lt n gt where lt n gt specifies User Set 1 or User Set 2 To use one of the two user saved sets or one of the read only factory sets enter the following command CONFIG PARSET LOAD lt n gt where lt n gt specifies one of the following parameter sets 1 user set 1 2 user set 2 3 factory set 1 n 4 factory set 2 n n n To return which set of parameters is presently active enter the query CONFIG PARSET ACT where 1 2 3 or 4 is returned corresponding to the parameter sets listed above To designate which parameter set will be used the next time the system is booted enter the command CONFIG PARSET BOOT n where n specifies 1 2 3 or 4 to correspond to the parameter sets listed above To find out which set of parameters will be activated the next time the sys tem is booted enter the query CONFIG PARSET BOOT where 1 2 3 or 4 is returned corresponding to
126. ghly coincident with the laser pulses OptoSync as well as Burst mode and First Pulse Suppres sion A description of these capabilities is provided in Chapter 3 1 1 Explorer Actively Q Switched High Repetition Laser Systems Table 1 1 High Repetition Rate Explorer OEM Models Explorer Part Number Wavelength nm Ave Power mW Max PRF kHz EXPL 355 300 E 355 300 60 EXPL 355 300 P 355 150 150 EXPL 532 1W E 532 1000 60 EXPL 532 1W P 532 1000 150 EXPL 532 2W E 532 2000 60 EXPL 532 2W P 532 1800 150 EXPL 532 200 E 532 2000 60 Some of the advantages of the Explorer laser are e Actively Q switched e High peak power e Variable repetition rate e Superior pulse to pulse stability e Variable pulse energy e Reliable rugged design e Excellent mode quality e Low jitter The Explorer Laser Head Note g The Explorer laser system was specifically designed for applications requiring a Q switched high quality beam with an adjustable repetition rate along with good mode quality in a cost effective package Explorer is a rugged sealed unit designed for simple hands free operation Sufficient cooling for the laser head must be provided The laser head can be air cooled using the optional fan cooled heat sink or it can be cooled by con duction through a user provided heat sink All optical components are contained in the laser head itself These include the laser crystal the diode laser pump source and the nonlinear cryst
127. ginal temperature set points by activating the preset Factory 1 Settings Tab Display Note g L Win GUI Reference Si win vi E 0 xl Power Control Temp Control Settings Calibration Settings pulse energy calibration Factor GUI only Jj 1 00 Start Emission without key switch reset Auto On Activate Preset Store Settings in Boot with Preset Power Supply Preset User 1 T User 1 vg User 1 vy Figure A 8 Settings Tab Display The Settings tab display has controls for setting storing and loading system parameter sets called presets that are defined by the user or by the fac tory This tab also allows the calibration display factor to be set and the Auto On mode to be enabled disabled Pulse energy calibration factor field sets a correction factor for the measured pulse energy or average power display in the Status Panel see Figure A 2 on page A 2 With a value of 1 the display shows the unchanged pulse energy values delivered by the power sup ply in response to the query READ PENER READ POW The calibra tion factor can be changed to correct the displayed values to correspond to your external energy meter This factor is used only for the GUI display It is not stored in the power supply Auto On button enables or disables the Auto On mode which overrides the need for a keyswitch reset turning the keyswitch off and on to turn the system on with a serial command N
128. gt lt LF gt gt DIOD1 CURR lt CR gt lt 4 56A1 lt CR gt lt LF gt The diode laser current has been set to 4 56 Amps DIOD1 MAXC This command returns the diode laser current limit in Amps The diode current limit is set at the factory Example gt DIOD1 MAXC lt CR gt 5 5A1 CR LF B 23 Explorer Actively Q Switched High Repetition Laser Systems DIOD1 STANDBYC This command reads the diode laser standby current in Amps Example gt DIOD1 STANDBYC lt CR gt lt 0 5A1 lt CR gt lt LF gt DIOD1 TEMP f DIOD1 TEMP This command sets the diode laser temperature in degrees C 18 0 lt f lt 38 0 Unit degC Examples gt DIOD1 TEMP 29 2 lt CR gt lt lt CR gt lt LF gt gt DIOD1 TEMP lt CR gt 29 2degC lt CR gt lt LF gt FPS DELAY lt n gt FPS DELAY This command sets the FPS delay time to lt n gt usec Unit usec Range lt n gt O lt ns 2000 n 0 disables FPS Examples gt FPS DELAY 678 lt CR gt Set FPS delay is 678 usec lt lt CR gt lt LF gt gt FPS DELAY lt CR gt lt 678usec lt CR gt lt LF gt gt FPS DELAY 0 lt CR gt Disable FPS lt CR gt lt LF gt HEAD BAS TEMP MAX This indicates the warning level of the laser head base plate temperature in degrees C An over temperature warning will be issued if the temperature rises above this maximum and a safety shutdown occurs if the temper
129. he Explorer Laser Head Overview Optical Design The Explorer laser head is designed for maximum reliability with mini mum complexity No adjustments to the laser head are needed for normal operation In addition to the optical components see Figure 3 1 the laser head contains microprocessors and memory for storing system parameters for example the last operating settings These parameters are up loaded to the L Series power supply when the system is turned on The Explorer laser head integrates several key components including a newly developed fiber coupled single emitter pump laser diode as well as the 40 MHz Q switch driver Models include detection circuitry to either measure the energy of individual pulses or measure the average output power of the laser The 808 nm output of the single emitter diode laser inside the laser head is coupled into the laser crystal by means of a fiber optic cable The diode laser itself is incorporated in a module that is mounted directly on a tem perature regulated cold plate to stabilize its output wavelength The Explorer software allows the diode laser current and temperature to be adjusted when necessary The output of the fiber is focused into the laser crystal by a beam shaping telescope The laser crystal absorbs the 808 nm pump light and is energized to produce a high quality laser beam at 1064 nm The energy of this output is concentrated into a series of intense pulses using an acousto
130. his Spectra Physics manual Quantity Unit Abbreviation mass kilogram kg length meter time second S frequency hertz Hz force newton N energy joule J power watt W electric current ampere A electric charge coulomb C electric potential volt V resistance ohm Q temperature Celsius C angle radian rad Prefixes tera 107 T deci 10 d nano 109 n giga 10 G centi 107 c pico 107 p mega 10 M milli 10 m femto 10 f kilo 10 k micro 109 u atto 10 a XV Abbreviations The following is a list of abbreviations used in this manual ac AOM AR CDRH CW dc FPS fs HR IR OEM OC ps RF rpm SHG TEC TEM THG UV alternating current acousto optic modulator anti reflection Center of Devices and Radiological Health continuous wave direct current first pulse suppression femtosecond or 10 second high reflector infrared original equipment manufacturer output coupler picosecond or 107 second radio frequency rotations per minute second harmonic generation thermoelectric cooler transverse electromagnetic mode third harmonic generation ultraviolet wavelength xvii Unpacking and Inspection Unpacking the Laser Your Explorer laser was packed with great care and its container was inspected prior to shipment it left Spectra Physics in good condition Upon receiving your system immediately inspect the outside of the ship ping containers If there is any major
131. ical Four level Transition Scheme A four level scheme has a distinct advantage over three level systems where E is both the origin of the pumping transition and the terminus of the lasing transition Over half of the atoms must be pumped from E before an inversion is established in the three level system D 3 Explorer Actively Q Switched High Repetition Laser Systems Resonant Optical Cavity D 4 To sustain lasing action the gain medium must be placed in an optical cav ity The latter can be defined by two mirrors which provide feedback to the active medium i e photons emitted parallel to the cavity axis are reflected back into the cavity to interact with other excited states Stimulated emis sion produces two photons of equal energy phase and direction from each interaction The two photons become four four become eight and the numbers continue to increase geometrically until an equilibrium between excitation and emission is reached The laser oscillates within a narrow range of frequencies around the transi tion frequency The width of the frequency distribution the linewidth and its amplitude depend on the gain medium its temperature and the magnitude of the population inversion Line width is determined by plotting gain as a function of frequency and measuring the width of the curve where the gain has fallen to one half max imum full width at half maximum or FWHM Figure D 3 Longitudinal Modes
132. ical response SPECTRA PHYSICS EXPLORER 532 1000 100KP PL 0332 02 PS 0129 01 V4 00 44 V4 01 154 lt CR gt lt LF gt If the laser head communication fails SPECTRA PHYSICS EXPLORER 532 1000 100KP XXXXXXX PS 0129 01 999V4 01 154 lt CR gt lt LF gt MODE RMT lt n gt MODE RMT This command enables n 1 or disables n 0 Computer remote mode Computer mode must be enabled to turn the laser on or off via the RS232 serial port Examples gt MODE RMT 1 lt CR gt Places the system in Computer mode and the laser is turned on by sending the ON command while the power supply key switch is in the ON position gt MODE RMT 0 lt CR gt Places the system in Local analog mode and the laser is turned on by turning the key switch to the ON position or by processing the EXTERNAL_DIODE_ON line of the analog interface gt MODE RMT lt CR gt Queries the setting for the Remote mode CONT AUTOON lt n gt CONT AUTOON This command sets the Auto on feature of the laser system n 1 enables Auto on mode The ON command starts laser emission without a keyswitch reset i e turning the key OFF and ON n 0 disables Auto on mode After the system is booted or after a critical error a keyswitch reset i e turning the key OFF and ON is necessary to start laser emission with the ON command SYST COMM SER BAUD lt n gt SYST COMM SER BAUD This command sets the communication speed baud rate between the Ex
133. ice provided by the user or by software written by the user the following criteria must be met in order to comply with recognized safety agency requirements e A keyswitch must be employed that limits access to the laser and prevents it from being turned on It can be a real key lock a removable computer disk a password that limits access to computer control software or any similar key implementation The laser must only operate when the key is present and in the on position e An emission indicator must be used to indicate that laser energy is present or can be accessed It can be a power on lamp a computer display that flashes a statement to this effect or an indicator on the control equipment for this purpose It need not be marked as an emission indicator as long as its function is obvious Its presence is required on any control panel that affects laser output 2 5 Explorer Actively Q Switched High Repetition Laser Systems CE Radiation Control Drawings Refer to CE Warning Labels on page 2 7 Emission Indicator white LASER HEAD Diode Laser ON OFF Keyswitch POWER SUPPLY LED indicators DC Power ON OFF Switch Figure 2 5 Explorer Radiation Control Drawing CE Warning Labels VISIBLE AND OR INVISIBLE LASER RADIATION IS EMITTED FROM THIS APERTURE SEE MANUAL Laser Safety AVOID EXPOSURE EMISSION CONTROL Aperture Symbol Aperture Warning Emission Indica
134. ied to the EXT DIODE ON pin pin 10 of the ANALOG IN port Either internal or external triggering may be used Only EXPL xxx yyy E models 2 Only EXPL xxx yyy P models 7 13 Explorer Actively Q Switched High Repetition Laser Systems 7 14 2 Wait until the laser system temperature has stabilized before starting the pulse energy adjustment procedure i e wait until operational bit 12 is activated use the command STAT COND OPER to query this pin For EXPL xxx yyy E Lasers Start this procedure using the command CONT PENER n n n4 where n is the requested pulse energy nz states the desired pulse rep etition frequency and n4 determines whether the user parameters will be stored after completion If this procedure is successful the requested diode current and repetition rate are set as the new input values if internal triggering mode is on These values can be verified by using the command CONT PENER which displays the new diode current and pulse energy If this procedure fails the command CONT PENER displays a question mark Review the chart in Figure 3 4 on page 3 7 to make sure the laser is capable of delivering the energy requested for the given pulse frequency For EXPL xxx yyy P Lasers Start this procedure using the command CONT POW n n n4 where n is the requested average pulse power n states the desired pulse repetition frequency and n5 determines
135. ignal STAT COND SYST DIOD1 This command reads diode laser status refer to Table C 2 Example gt STAT COND SYST DIOD1 lt CR gt lt 2 lt CR gt lt LF gt Diode laser current control error STAT COND SYST HEAD This command reads laser head status refer to Table C 2 Example gt STAT COND SYST HEAD lt CR gt lt 1 lt CR gt lt LF gt There was a communication error with the laser head STAT COND SYST PARSET This command reads data administration status refer to Table C 2 Example gt STAT COND SYST PARSET lt CR gt lt 16 lt CR gt lt LF gt An error occurred while loading the user parameter set STAT COND SYST PSUPPLY This command reads power supply status refer to Table C 2 Example gt STAT COND SYST PSUPPLY lt CR gt lt 1 lt CR gt lt LF gt There is an overtemp condition on the power supply board STAT COND SYST TCONT This command reads temperature controller status refer to Table C 2 Example gt STAT COND SYST TCONT lt CR gt 32 lt CR gt lt LF gt PWM controller for diode laser temperature failed B 33 Explorer Actively Q Switched High Repetition Laser Systems STB This command reads the system status byte refer to Table C 1 Example gt STB lt CR gt lt 1 lt CR gt lt LF gt Laser emission is present SYST COMM SER BAUD lt n gt SYST COMM SER BAUD
136. igure A 2 Status Panel Pulse Energy emission Average Power mW command error system error std event i 1018 500 1000 1500 A 2000 status byte operational System Status No Error RS 232 comm error 0 Figure A 3 Status Panel Average Power The Status Panel displays system status information There are two possi ble editions one for lower rep rate systems that shows pulse energy Fig ure A 2 and one for higher rep rate systems that shows average output power Figure A 3 The display is updated once per second Status byte indicators display bits of the system status byte This byte can be also be read with the STB serial query Refer to Table C 1 on page C 1 for a description Emission indicator turns on when laser emission is present Command error indicator turns on when a command fault is detected such as an unknown command or invalid parameter System error indicator turns on when a system fault is detected such as a temperature fault Std event indicator turns on if a standard event occurs e g interlock active system boot watchdog tripped etc Operational indicator turns on if certain operational conditions are fulfilled e g Standby Burst mode RS 232 comm error indicator turns on when an error is detected on the RS 232 communication link caused for example by a missing RS 232 cable or a switched off power supply Pulse Energy bar and number field display
137. in Software Important Notes on Controlling Explorer Output Explorer laser output power is controlled by changing the diode laser cur rent Diode current can be varied as needed but the maximum diode laser current allowed is pre set at the factory There is no lower diode current limit However no laser light will be emit ted if the diode current is lowered below the laser threshold If the diode current is lowered close to the laser threshold unstable operation might result Changing diode current will change the temperature of the diode laser and hence the wavelength of its emission Failure to maintain the diode emis sion at the proper wavelength can actually cause a decrease in output power when diode current is increased A Cautionary Note on Changing Power Caution Explorer systems are specified and tested for the highest power they can reliably output The laser must not be operated at power levels higher than this tested level refer to the Ship Report included with the system Over driving the system can cause spatial mode degradation and Q switch hold off problems which can shorten the diode laser lifetime Output power levels may be reduced if the application requires lower power Since diode laser lifetime is strongly a function of current reducing this current can extend the lifetime of the diode laser However reducing pump power might impact other performance parameters of the laser out put For examp
138. ing current set Set actual 1j 50000 Hz 50000 Hz emission Average Power mW 822 system error 1 1 I std event 500 1000 1500 2000 operational System Status No Error RS 232 comm error 0 Figure 6 1 The L Win Main Display To start the laser set the Trigger switch to Internal and click on the Emission button The button will turn green the power supply and laser head emis sion indicators will turn on immediately and a pulsed beam at the dis played pulse repetition rate will be emitted after a 3 second safety delay To turn the laser off click on the Emission button again The button will turn gray and the laser will turn off Operating Using the L Win Software Note 9 If the Control mode toggle switch on this display is set to Analog for external control the Emission control switch on this display is disabled Keep the toggle switch set to RS 232 to operate the laser using the L Win controls Adjusting the Pulse Energy and Average Power Note To change the pulse energy and the average power of the laser beam adjust the diode laser current The current can be changed by clicking on the up down arrows to the left of the Current Set field or a value can be typed directly into the text field Note that the current can also be varied as a percentage of the maximum pre set current limit This is enabled by set ting the Current Set toggle switch to The display will then switch from Amps
139. invisible and is therefore especially dangerous Residual light at 1064 nm 808 nm and 532 nm wavelengths might also be present Note g This is an OEM laser product and as such does not conform to the safety specifications and performance standards required of a Class IV laser as defined by the Center for Devices and Radiological Health CDRH 21 CFR 1040 Precautions For The Safe Operation of Class IV High Power Lasers Wear protective eyewear at all times Selection depends on the wavelength and intensity of the radiation the conditions of use and the visual function required Protective eyewear is available from suppliers listed in the Laser Focus World Lasers and Optronics and Photonics Spectra buyer s guides Consult the ANSI and ACGIH standards listed at the end of this section for guidance Maintain a high ambient light level in the laser operation area so that the eye s pupil remains constricted reducing the possibility of damage Avoid looking at the output beam even diffuse reflections are hazardous Avoid blocking the output beam or its reflections with any part of the body Establish a controlled access area for laser operation Limit access to personnel trained in the principles of laser safety Enclose beam paths wherever possible Post prominent warning signs near the laser operating area Figure 2 1 Install the laser so that the beam is either above or below eye level Set up shields to prevent
140. is key to achieving proper system performance including cold start performance At normal ambient operating temperature 25 C the Explorer laser head generates about 40 W of heat that must be dissipated by the heatsink to which the laser head is mounted Spectra Physics offers an optional custom heatsink that includes a fan for use with the Explorer laser head contact your Spectra Physics representa tive for more information The auxiliary fan attached to the heatsink is controlled through the L Series power supply A temperature sensor inside the housing continuously measures the laser head temperature and its feed back is part of an active servo loop that is used to set the fan RPM For more information refer to Thermal Management in Chapter 5 and Con trolling the Laser Head Temperature in Chapter 7 Explorer Actively Q Switched High Repetition Laser Systems The L Series Power Supply System Control The L Series power supply provides the drive current for all of the active components inside of the laser head including the thermoelectric coolers TEC the diode laser the Q switch driver the microprocessors and non volatile memory It also provides the communication and control interface for the user The air cooled power supply requires a 24 2 Vdc 4 A electrical source and it is capable of suppling up to 10 A of diode laser drive current A small fan inside the supply ensures proper cooling The rugged L Seri
141. isplays Burst mode status Loop Time field sets the delay time between the end of one burst until the next burst command is sent to the system in milliseconds For example setting the interval to 200 ms will cause an interval of approximately 200 ms plus number of pulses per burst times the 1 pulse repetition frequency between two bursts Please note that the interval between two bursts is not very precise because the system sta tus is polled via RS232 commands For more precise burst timing use TTL triggering on the ANALOG IN port or for less precision use the BURST command via RS232 using a well defined software timing loop STOP button closes the window Pulse energy field chronologically displays the energy of each pulse in a burst 1st Pulse field displays the energy of the first pulse of the burst 1st Pulse Error in field displays the discrepancy as a percent age between the first pulse s energy and the mean energy of the other pulses Pulses 2nd to end mean field displays the calculated mean energy of all pulses except the first sigma in field displays the value of the standard deviation of all pulses excluding the first Waveform Graph display shows one vertical bar for each pulse in a burst showing its energy in relation to other pulses Graph Display button turns the graphical pulse display on and off Explorer Actively Q Switched High Repetition Laser Systems Pulse
142. l may not be available When this is the case the temperature controls are displayed with 0 and are greyed out as shown in Figure A 5 Diode temperature fields provide a means to set the desired temper ature of the pump diode and to display the measured temperature in C SHG temperature fields provide a means to set the desired temper ature of the second harmonic crystal and to display the measured tem perature in counts THG temperature fields provide a means to set the desired temper ature of the third harmonic crystal and to display the measured temper ature in counts Diode Hours field displays the total number of hours the diode pump laser has been operated Pulse Count kcts or Mcts field displays the total number of pulses in thousands of pulses kcts for low rep rate systems or mil lions of pulses for high rep rate systems Mcts that the laser has emit ted during its lifetime The pulse counter is set to 0 prior to shipment Note Upon GUI start up the system enters Standard mode where the set temperatures and the measured temperatures are displayed but the temper atures cannot be changed To change temperature settings switch to Expert mode by selecting View GUI Mode from the L Win Main display Figure A 6 ome Mer Mode Power Control Temp Control settings serial port GA nertra_l Figure A 6 Selecting the GUI Mode A 5 Explorer Activel
143. l of the Pulsed Output 0 0 0000 tees 6 14 Burst GODlIOl nias tme enr ee ease bx sie ee qun ee eRe toes area ate 6 14 FPS Operation ss setts srt Sok pal Rege Eee ptu Es wee ve d rtt 6 15 Important Notes on Controlling Explorer Output 00 0000 cc meh 6 17 A Cautionary Note on Changing Power i ssssselse nr 6 17 Working with the Diode Laser Current Limit lssesse eh 6 17 Chapter 7 Operating with Commands and Signals 7 1 Serial Communication ssessseee erm 7 2 Connection and Parameters isssseeee err 7 2 Serial Command Query Language sssssssseeeee n 7 2 Serial Communication Through the L Win GUI 0 00 00 eee 7 2 Basic Serial Operating Control 0 0 00 cc mne 7 3 Serial vs Analog Control issssseseeseee hmmm 7 3 Turning the Laser On and Off sslisssssessssee hs 7 8 The Watchdog Timer iara keera Ere RR ER bh Gl Bebe edd ARR Li 7 3 Adjusting the Pulse Energy or Average Power 2 00 e eee ett tte 7 4 Changing the Q Switch Trigger Source 0 0 saasaa eaae 7 4 Monitoring the System Status Byte auauua aaa 7 4 Tracking Diode Laser Operating Hours 2 00 0 cece eee 7 5 Changing the Pulse Repetition Frequency sssssseselss eee 7 5 Setting the Laser to Standby or Sleep Mode liiis 7 6 Saving and Using Operating Parameters iilii ees 7 7 Setting the Auto On Mod
144. laser cannot be resolved after using this g basic troubleshooting section contact your Spectra Physics service rep resentative for further assistance Contact information for service cen ters is provided at the end of this chapter 8 1 Explorer Actively Q Switched High Repetition Laser Systems Symptom No laser beam Possible Causes Corrective Action No ON signal applied to the power supply Review the instructions for operating the laser in Chapters 6 and 7 Improper power supply DC voltage Verify that input voltage is 24 Vdc 2 V Loose cable connector Check that all cables are securely connected Burst Mode is active but there is no Burst Either deactivate Burst Mode or supply a proper Burst Mode sig Mode signal nal Standby or Gate signal is active onthe Remove the Standby or Gate signal from the ANALOG port Analog Port Symptom Low power Possible Causes Corrective Action Laser is not warmed up Allow the laser to warm up for at least 5 minutes Dirty output window Clean the laser head output window Laser head temperature is outside the Verify that the laser head base plate is properly heatsinked operating range Reflected laser light is destabilizing the Ensure that light reflected from any external optical elements laser does not directed back through the window of the laser head Nonlinear crystals require temperature Refer to the section Setting the SHG and THG Temperatures in optimization Chapte
145. le it is common for pulsed solid state lasers to change pulse width when the pump power changes Decreasing pump power will lower optical gain and result in a broadening of the pulse width This might also result in higher pulse to pulse instability Working with the Diode Laser Current Limit To ensure long system lifetime the Explorer laser head achieves specified output power using a level of pump power that is lower than the maximum rating of the pump diode laser To protect the diode laser a current limit is imposed that prevents an over driven situation that could damage the diode laser or even the Explorer itself When new the diode laser module achieves its rated output power using a fraction of the current required at its end of life Higher drive current is necessary later in the diode life in order for the laser to achieve its specified output power Explorer Actively Q Switched High Repetition Laser Systems 6 18 Chapter 7 Operating with Commands and Signals X Danger Spectra Physics Explorer lasers are Class IV High Power Lasers Laser Radiation whose beams are by definition safety and fire hazards Take precau tions to prevent accidental exposure to both direct and reflected beams Diffuse as well as specular beam reflections can cause severe eye or an skin damage The ultraviolet beam at 355 nm is invisible and is there Eyewear g fore especially dangerous Residual light at 1064 nm 808 nm and Required 5
146. ler HEAD FANCONT TEMP HEAD FANCONT TEMP lt f gt set temperature for fan control HEAD FANCONT SPEED HEAD FANCONT MODE lt n gt return actual set temperature for fan control read the control voltage frequency of the fan in DAC counts 200 1000 cents set operation mode for fan control control or drive mode constant voltage HEAD FANCONT MODE HEAD FANCONT PVOLT lt f gt HEAD FANCONT PVOLT Pulse Energy READ PENER return operation mode for fan control control or drive mode constant voltage set fan control voltage in drive mode in 13V return fan control voltage in drive mode in 13V read actual output pulse energy in uJ x RRR GR PORE EET X LEE LIE LI X PENER CALF READ PENER HIST PENER REFVOLT CNTS PENER REFVOLT CNTS n Output Power READ POW POW CALF return the actual pulse energy calibration factor In uJ cnt return a list of pulse energies last 50 pulses in ADC counts return reference voltage in counts for pulseenergy measurement set reference voltage in counts for pulse energy measurement read actual average power in mW return the power calibration factor in mW cnt X X Pt TT Ut I LLL ET idik LI ff txt 7 POW REFVOLT CNTS POW REFVOLT CNTS lt n gt Status Errors READ FAULT return reference voltage in counts for power measurement set reference voltage in counts for power measurement read
147. m is obtained by frequency tripling the funda mental IR laser output at 1064 nm This conversion is accomplished using two separate LBO crystals A portion of the fundamental beam is first dou bled to 532 nm in the SHG LBO crystal then this frequency doubled light is mixed again with the fundamental wavelength in the third harmonic generation THG crystal to produce the final ultraviolet output beam Again the nonlinear wavelength conversion takes place entirely inside the laser head A specially coated mirror directs the ultraviolet light out of the laser cavity while confining the green and infrared wavelengths The LBO crystals must be heated and temperature stabilized to maintain good conversion efficiency The Explorer software and command structure provide the ability to adjust the temperatures of these crystals when neces sary The Explorer Laser System Pulse Energy and Average Power Monitors A small fraction of the laser output is reflected into a detector not shown in Figure 3 1 For models with a repetition rate up to 60 kHz measure ment is provided as an individual pulse energy value For those with higher repetition rates average power is measured For single pulse measurement the detector generates several signals that are evaluated by the microprocessor including the energy of each pulse The analog value of this pulse energy is stored by a sample and hold cir cuit and it becomes the laser output power value until i
148. mission is on Figure 4 6 DC IN Power Connector Table 4 2 DC IN Power Connector Pinout Pin Signal 1 2 4 Return 3 5 8 24 Vdc 6 Emission relay max 48 Vdc 1 A 7 Emission relay return Explorer Actively Q Switched High Repetition Laser Systems Rear Panel Connections 4 6 Warning Y a oo Detail a 090 Fan Connector LASERHEAD 1 ui 999 123456 5 HHHEBH W 0 20 00000000 o o9o oooooo O lt o9 O gt Fan Laser Head Laser Head Connector Cable 1 Cable 2 Connector Connector Figure 4 7 Power Supply Rear Panel FAN connector 6 pin RJ12 provides variable DC power for an auxil iary cooling fan The fan voltage is dependant on the thermal load gener ated by the Explorer laser head The FAN connector is an 8 pin Western Modular socket It provides up to 250 mA at 13 Vdc Table 4 3 below describes the pins of this connector Table 4 3 FAN Connector Pinout Pins Signals 1 2 3 Fan return 4 5 6 Fan out Use this connector for connecting to a cooling fan only Never connect any other equipment e g telecommunication devices to this connector LASERHEAD 1 connector 15 pin D sub female provides attachment for a control cable that connects to the laser head Laser Head Cable 1 male 15 pin connector This connector provides the diode laser drive cur rent and the drive current for the TECs used by some optical components in the las
149. mount of energy used Standby Mode Standby mode lowers the current of the diode laser below the threshold for laser output but keeps the diode laser in a state of readiness All other Explorer components are maintained at operating temperature Use this mode when the laser is to be used again soon To enter Standby mode enter the command MODE STBY 1 To see if the laser is in Standby mode enter the query MODE STBY 1 Standby mode is on 0 Standby mode is off To return from Standby mode enter MODE STBY 0 Sleep Mode Sleep mode turns off the diode laser the Q switch and temperature control for the diode and crystals Everything else is still on This allows the sys tem to be returned to operation via a software command instead of requir ing a hardware start using the keyswitch Use this mode when the laser is not to be used for quite some time e g over night To enter Sleep mode enter the command MODE SLEEP 1 Operating with Commands and Signals To return from Sleep mode enter MODE SLEEP 0 To see if the laser is in Sleep mode enter the query MODE SLEEP 1 Sleep mode is on 0 Sleep mode is off Note Sleep can only be activated when laser emission is off While in Sleep mode all commands to the laser except status queries and MODE SLEEP 0 are ignored Saving and Using Operating Parameters As a short cut to activate a desired state of laser operation the Explorer system allows the use of stored s
150. ms 8 12 Appendix A L Win GUI Reference This appendix contains a screen by screen reference for the L Win control software provided with the Explorer laser For a description of some com mon operating procedures using the L Win interface refer to Chapter 6 L Win Main Display The L Win Main display consists of e Menu bar Tools menu e Control section Power Control Temp Control and Settings tabs e Status panel Tools View Menu Bar D Power Control Temp Control Settings serial port S Spect Phy e d ra Physics l L Win AsER coNTROL v1 2 0 Emission SPECTRA PHYSICS EXPLORER 532 1000 100KP P V 0080 B62 ENG Control Section ON PS 0272 B02 ENG Vv4 00 39Q 100 C N4 00 111 OFF Standby Utilities Control Pump Repetition Rate mode Current set Tilgger ana RS J 40 A log 232 i internal gt external dh measured E ap 14 0 A Set actual o x joo H S0000 Hz emission Average Power mW 2 command error i o gt Status Panel 4 dise aid 0 500 1000 1500 2000 B std event i amp MI operational System Status No Error RS 232 comm error 0 Figure A 1 L Win Main Display Explorer Actively Q Switched High Repetition Laser Systems Status Panel A 2 emission Pulse Energy J command error Se Sic system error 1 I 1 I std event O0 10 20 30 40 50 60 operational o a gt 4a wu 4i m a wu System Status No Error RS 232 comm error 0 F
151. n West Spectra Physics K K Nishi honmachi Solar Building 3 1 43 Nishi honmachi Nishi ku Osaka 550 0005 Japan Telephone 8 1 6 4390 6770 Fax 8 1 6 4390 2760 E mail spectra physics splasers co jp And all European and Middle Eastern countries not included on this list Maintenance and Service Netherlands Newport Spectra Physics B V Vechtensteinlaan 12 16 3555 XS Utrecht Netherlands Telephone 0900 555 5678 Fax 0900 555 5679 E mail netherlands newport de com Taiwan Newport Corporation Room A 10F No 80 Sec 1 Jianguo N Rd Zhongshan District Taipai City 104 Taiwan R O C Telephone 886 2 2508 4977 Fax 886 2 2508 0367 E mail sales newport com tw United Kingdom Newport Spectra Physics Ltd Registered Office Unit 7 Library Avenue Harwell Science amp Innovation Campus Didcot Oxfordshire OX11 OSG Telephone 44 1235 432710 Fax 44 1235 821045 E mail sales newport com uk United States and Export Countries Newport Spectra Physics 3635 Peterson Way Santa Clara CA 95054 2809 Telephone 800 456 2552 Service or 800 SPL LASER Sales or 800 775 5273 Sales or 408 980 4300 Operator Fax 408 980 6921 E mail service spectra physics com sales spectra physics com Web site Wwww spectra physics com And all non European or Middle Eastern countries not included on this list 8 11 Explorer Actively Q Switched High Repetition Laser Syste
152. n excited electrons quickly drop from one of the pump bands into the Fs level the upper level of the las ing transition They remain for a comparatively long time until stimulated to emit a photon 20 Pump r 4 Bands 18 16 AF 2 14 PEE c eiu 2 cad fm 10 Laser Fs Transition SZE Laser n P Transition SU Fam 4 r ad a 6 Alis PS aes a d FF 4 hse p E 2 F 4hae 2 4 Fgo 9 2 o R T lt Figure D 4 Energy Level Scheme for the Nd Ion The transition to a lower laser state produces an infrared photon Because electrons then quickly relax to the ground state the lower laser state popu lation remains low making it easy to build a population inversion The likelihood of stimulated emission for this transition is high so it takes rela tively few photons of the correct wavelength which are always randomly available to start the process There are several competing transitions from the same upper state to the different lower states resulting in several wave lengths possibly being produced Wavelength selective optics are used to limit emission from the laser crystal to the desired wavelength D 5 Explorer Actively Q Switched High Repetition Laser Systems Vanadate possesses several benefits for use in a high repetition rate solid state laser Although it has a comparatively short lifetime only about 100 us it has a ver
153. n Laser Systems A 18 Note The System Settings Summary display retrieves the values of all configura tion and history parameters by automatically sending the relevant query commands to the laser system and displays the system responses The mouse and scroll bar can be used to browse the list Laser Serial Port field provides a pull down menu for selecting the serial port to be used for the communication link with the laser Show Commands button turns the command query display on and off Read button retrieves the current list of parameters and settings Store button prompts the user for a path and file name and stores a copy of the list to that file Quit button closes the window If the laser is turned on while the Read button is being pressed the laser will shut off This behavior is designed to insure that the read captures all parameters Please note that some queries will be answered by because not all parameters are accessible in user mode Appendix B Explorer Programming Guide Serial commands and queries can be used to create programs to allow the master system computer to operate the Explorer laser Each command is acknowledged by a carriage return cR and line feed lt LF gt If a command is not successfully executed unknown command command not allowed or invalid parameter the system responds with a question mark 6 Commands are not case sensitive This appendix contain
154. n indicator turns on immediately OFF Turn the diode laser off MODE STBY lt n gt MODE STBY This command enables disables the Standby mode for the diode laser refer to Setting the Laser to Standby Modes in Chapter 7 for a description of Standby mode Range lt n gt n 1 enable standby mode n 0 disable standby mode and turn laser on again if previously switched on B 3 Explorer Actively Q Switched High Repetition Laser Systems Diode Current DIOD1 CURR lt f gt DIOD1 CURR This command sets the diode laser current in Amps 0 lt f lt maximum diode laser current value in Amps i e the value returned by DIOD1 MAXC in the form xx xx Commands with values outside this range are rejected Examples gt DIOD1 CURR 4 56 lt CR gt Set the diode laser current to 4 56 Amps lt lt CR gt lt LF gt gt DIOD1 CURR lt CR gt lt 4 56A1 lt CR gt lt LF gt The diode laser current has been set to 4 56 Amps READ DIOD1 CURR This command reads the actual diode laser current in Amps Unit A1 Example gt READ DIOD1 CURR lt CR gt lt 4 56A1 lt CR gt lt LF gt PCUR lt f gt PCUR This command sets the diode laser current as a percentage of the maximum current limit lt f gt current in percent of value returned by DIOD1 MAXC Unit 1 Examples gt PCUR 34 6 lt CR gt lt lt CR gt lt LF gt gt PCUR lt CR gt 34
155. n of the output signal is 12 bit which corresponds to a maximum signal of 4 095 V For the EXPL xxx yyy E laser the output signal gets latched through a sample and hold circuit and is refreshed prior to each new laser pulse thus providing single pulse energy measurement capability For the EXPL xxx yyy P laser average output power via pin 1 is refreshed about every 1 ms asynchronously to the optical pulses Note that pin 22 is the ground pin on the ANALOG IN connector that should be used with pin 1 External Sync OptoSync Operating with Commands and Signals 5V O O d gt lt m Pin 1 74ACTxx AA N 0 47 Q 9 Pin 22 Gnd gt T3 L Series Figure 7 5 Pulse Energy Average Output Power Circuit The External Sync output on pin 19 is synchronized to the internal Q Switch trigger and can be used as a trigger pulse for synchronizing mea surement equipment to the pulsed laser output Figure 7 6 shows the circuit for the output signal at pin 19 The timing and jitter of the trigger signals is shown in Figure 7 7 5V O O gt amp Pin 19 External Sync Output PAG TRE a Pin 14 OptoSync Output Q gt o Oo Z r o Pin 24 Gnd oO L Series Figure 7 6 External Sync Out and OptoSync Circuit The OptoSync output on pin 14 of the ANALOG IN connector referenced to pin 24 provides a trigger signal for measurement equipment with very low jitter Figure 7 6 shows the circuit for
156. ncy Frequency CONT PENER CONT PENER CONT POW CONT POW Power Explorer Model Hz Hz uJ uJ mW mW EXPL 355 300 E 20000 60000 10 uJ V EXPL 355 300 P 20000 150000 150 mW V EXPL 532 1W E 60000 20 yuJ V EXPL 532 2W E 60000 20 W V EXPL 532 1W P 150000 500 mW V EXPL 532 2W P 150000 1000 mW V EXPL 532 200 E Single Shot 60000 100 uJ V The minimum and maximum pulse energy or average power in this table are the software limitation values Depending on the laser model and on the current laser configuration pulse repetition frequency for example these limits may not be achievable B 35 Explorer Actively Q Switched High Repetition Laser Systems Table B 4 Status Error Reporting Commands STATus CONDition SYSTem PARameterSET ERROR LOAD PS GLBL Reserved ERROR LOAD PS HISTORY ERROR LOAD HEAD GLBL ERROR LOAD HEAD USER ERROR LOAD HEAD HISTORY ERROR STORE PS GLBL ERROR STORE PS USER ERROR STORE PS HISTORY ERROR STORE HEAD GLBL ERROR STORE HEAD USER ERROR STORE HEAD HISTORY ERROR STORE LICENCE ERROR LOAD LICENCE STATus CONDition SYSTem HEAD ERROR COMMUNICATION ERROR CONFIGURATION ERROR PCB OVERTEMP ERROR RFPOWER ERROR HEATSINK OVERTEMP ERROR QSWITCH TIMING ERROR HEATSINK UNDERTEMP ERROR MODEL NUMBER ERROR NOT CONNECTED STATus CONDition SYSTem TempCONT ERROR TEMPCONTROLLER A COMM ERROR TEMPCONTROLLER B COMM ERROR DIODE1 TEMPCONTROL ERROR SHG TEMPCONTRO
157. ng registers through software commands a variety of triggering schemes can be used without the need for changes to the hardware Precise timing is realized by locking incoming signals to the microprocessor clock and using counters and regis ters to minimize jitter All L Series power supply inputs are protected from ESD Operational settings are stored in non volatile memory inside the laser head In case of a sudden power outage the power supply saves important system parameters in this non volatile memory thus ensuring that they are The Explorer Laser System secure In the event that the power supply is swapped out the operating parameters remain unchanged The laser head s permanent memory contains unit specific identification information and parameters such as maximum diode laser current The contents of permanent memory cannot be changed in the field Laser Head Temp Controller Cr F EN E Main Laser Head B Processor Processor P i i r i o i t 1 e i c i i i QSW Driver o i i n CPLD PWM PWM 5 Pulse Power Programmable Control Control 1 Measurment IND Logic 1 1 Figure 3 2 Explorer System Control Hardware Explorer Actively Q Switched High Repetition Laser Systems Laser Performance The energy of individual pulses increases in a fairly linear manner as the diode current is increased However pulse duration decreases sharply as the pulse energy is increas
158. nse to a query Appendix B provides more detailed information about the Analog Port Status Byte The query STAT APORT SIGNAL is used to read the status of a function available through the analog interface If this query returns 64 for exam ple it means that if bit 5 is active high the laser is in Standby mode To set the polarity of an individual pin to active high or active low enter the command CONFIG APORT POLAR The command CONFIG APORT POLAR 96 for example places a 1 in bit positions 5 and 6 corresponding to Standby and Go functions which are set to active high The query CONFIG APORT POLAR returns the setting of an individual pin If a 96 was returned for example it means that there are 1 s in bits 5 and 6 so those functions Standby mode and Go will be activated when the pins for them are pulled high Operating with Commands and Signals Component Temperature Adjustment Warning y Changing the temperature of the following components can cause seri ous damage to the laser Consult Spectra Physics before making any adjustments to these temperatures In order to function properly the diode pump laser and the harmonic crys tals in the laser head all depend strongly on operating at the correct temper ature These components are actively cooled or heated via closed loop control circuits The laser system also provides the ability to actively con trol an optional fan to cool the laser head m
159. nts Laser Safety Cover Safety Interlocks The Explorer lasers are OEM systems that are designed to be integrated into a master system that itself complies with regulatory requirements As such the laser head and power supply do not have cover safety interlocks The laser head and power supply covers are not to be opened by the user nor is the Explorer laser to be operated with the cover removed Maximum Emission Levels Table 2 1 lists the maximum emission levels possible for the Explorer lasers Use this information for selecting appropriate laser safety eyewear and to implement appropriate safety procedures These values do not imply actual system power or specifications Laser light at longer wavelengths is generated in the production of the green and ultraviolet emission and the diode pump laser used in all Explorer models produces infrared light These wavelengths are confined to the inside of the laser head Table 2 1 Maximum Emission Levels from Laser Head Emission Wavelength Max Power Max Pulse Energy Leakage Wavelengths Min Pulse Duration Laser Output 355 nm 1 W 0 1 mJ 5 ns Doubled Fundamental 532 nm lt 10 mW Diode Laser Emission 808 nm lt 10 mW Fundamental Beam 1064nm lt 10 mW Laser Output 532 nm 4W 1mJ 5ns Diode Laser Emission 808 nm 10 mW Fundamental Beam 1064 nm 10 mW System Operation Using a User Provided Control Device When the Explorer laser system is controlled by a dev
160. o drive the populations involved beyond equality that is V can never exceed N because every upward transition is matched by one in the opposite direc tion However if three or more energy levels are employed and if their relation ship satisfies certain requirements described below additional excitation can create a population inversion where N gt N A model four level laser transition scheme is depicted in Figure D 2 A photon of frequency v excites or pumps an atom from E to E If the E to E transition probability is greater than that of E to E and if the life time of an atom at E is short the atom will decay almost immediately to E If E is metastable i e atoms that occupy it have a relatively long lifetime the population will grow rapidly as excited atoms cascade from above The E atom will eventually decay to E emitting a photon of frequency 1 Finally if E is unstable its atoms will rapidly return to the ground state E keeping the population of E small and reducing the rate of absorption of 1 In this way the population of E is kept large and that of E remains low thus establishing a population inversion between E and E Under these conditions the absorption coefficient at v becomes negative Light is amplified as it passes through the material which is now called an active medium The greater the population inversion the greater the gain E4 E v2 V1 E4 Figure D 2 Typ
161. ode current are stored in the user parameter set 1 lt lt CR gt lt LF gt gt CONT POW 5 20000 1 lt CR gt Request to set the laser power to 5 mW 20kHz CR LF Request is denied because 5 mW is outside the valid laser power adjustment range Explorer Actively Q Switched High Repetition Laser Systems CONT POW This command reads the result of an automatic laser power energy adjustment Response lt f gt lt n gt determined diode current in Amps adjusted laser power in mW If the adjustment procedure failed the command returns Example gt CONT POW lt CR gt lt 1 93A 50mMW lt CR gt lt LF Data Administration CONFIG PARSET STOR lt n gt This command stores actual parameters as parameter set lt n gt refer to Table B 7 User Parameters Range lt n gt n 1 user parameter set 1 n 2 user parameter set 2 Example gt CONFIG PARSET STOR 1 lt CR gt lt lt CR gt lt LF gt CONFIG PARSET LOAD lt n gt This command loads parameter set lt n gt refer to Table B 7 User Parameters Range lt n gt n 1 user parameter set 1 n 2 user parameter set 2 n 3 factory settings 1 n 4 factory settings 2 Example gt CONFIG PARSET LOAD 1 lt CR gt lt lt CR gt lt LF gt CONFIG PARSET ACT This command reads the active parameter set number refer to Table B 7 User Parameters Range lt n gt 1 4 n
162. ode laser current limit in Amps This diode current limit is set at the factory and cannot be changed Changing the Q Switch Trigger Source The QSW PRF command sets the pulse repetition frequency see Changing the Pulse Repetition Frequency on page 7 5 It can also be used to set the Q switch trigger input to an external source applied to the power supply ANALOG IN connector To change to an external Q switch trigger source enter the command QSW PRF 0 Details for using an external trigger source are provided in The Analog Interface on page 7 15 To return to the internal trigger enter a number between 20000 and the number returned by QSW PRF MAX the maximum frequency Monitoring the System Status Byte 7 4 The system status byte returns a summary of important status information about the Explorer laser Appendix C describes each of the byte bits To monitor the system status byte enter the query STB 1 Only EXPL xxx yyy E models Only EXPL xxx yyy P models Operating with Commands and Signals Example STB 1 where 1 bit O of the status byte is set indicates that laser emission is present Refer to Table C 1 on page C 1 for other responses Tracking Diode Laser Operating Hours The system monitors diode laser operating hours of operation which is useful in tracking the lifetime of the diode laser and harmonic crystals To find out the total time the system has operated enter the query REA
163. of Federal Regulations 21 CFR1040 10 d Follow the instructions contained in this manual to ensure proper installa tion and safe operation of the laser Any electronic product radiation except laser radiation emitted by a laser product as a result of or necessary for the operation of a laser incorporated into that product Safety Devices Laser Safety Emission Indicator white Output Beam Figure 2 3 Laser Head Emission Indicator Diode Laser DC Power LED ON OFF ON OFF indicators Keyswitch Switch O POWER EMISSION O ERROR zileo o o o o o o o z o lt o o 00000 ooooj Front Panel Figure 2 4 Power Supply Safety Devices 2 3 Explorer Actively Q Switched High Repetition Laser Systems Emission and Power Indicators Shutter The system provides the following emission and power indicators e A white EMISSION indicator on top of the laser head Figure 2 3 turns on about 3 seconds before actual emission occurs A blue EMISSION indicator on the power supply front panel Figure 2 4 turns on about 3 seconds before actual emission occurs e A yellow POWER indicator on the power supply front panel Figure 2 4 turns on when the power switch is turned on e If the Explorer is operated using the L Win software an indicator on the L Win Main display turns green when the power switch is turned on the diode laser keyswitch is set to ON and the proper ON comman
164. oie tip ee epee de eben pee du EOL eS xix System COMPONENTS 4 seeder he aude PR ah ate MR hee RR LE ERE xix ACCESSO Kit oisi ePi reerpe p he wat ce edu b iM ee hs fee ENDE enixe EP xix Chapter 1 Introduction siet ERR ERE E Spe Ranae nek etwas cea lees 1 1 The Explorer Laser Head 2 0 ec m m 1 2 The L Series Power Supply lsusselseesese tees 1 3 System Gontroliz 22 o rueda SN Bad ees Salat eer Mti uos wings Peste ad ede dave eins Bele De vos gee aes 1 3 Patents nl ELE pair pete oa Ege e be een ar eT Se SET e i EE Us 1 3 Chapter 2 Laser Safety ciui co hREiG GR CK a dece eee neh Pee hl ER Vo Uf oe 2 1 Precautions For The Safe Operation of Class IV High Power Lasers lessen 2 1 Safety Devices s tee chao RH PEE REA UU REPRE DS UTBMIMICDEM RE RU Eh hs 2 3 Emission and Power Indicators 0 0 ccc rn 2 4 Stier c TUI 2 4 Diode Laser ON OFF Keyswitch ssslsseesees rrr 2 4 DC Power ON OFF Switch 5i enzeieta bee Ee Rae bg ec xt aise 2 4 Safety InterloCks 3 24 eme het daoweLkeses epp prt dM EIS fbirened adis oa 2 4 Maximum Emission Levels 0 000 cet m rn 2 5 System Operation Using a User Provided Control Device 0 0 0 0 ccc eee 2 5 CE Radiation Control Drawings 000 cette eee 2 6 CE Warming Labels 4 bevLIdowesbbtebetu eesedusrowo Reserved eb 4 tien ete IET 2 7 Label Translations 4 22 mim REG RIBERA R4 he bee oad weed Desde asbl d s 2 8 Waste Electrical and Electronic Equipm
165. on frequencies for the Explorer models Example gt QSW PRF MIN lt CR gt lt 20000Hz CR LF READ DIOD1 CURR This command reads the actual diode laser current in Amps Unit A1 Example gt READ DIOD1 CURR lt CR gt lt 4 56A1 lt CR gt lt LF gt The diode laser current is 4 56 amps READ DIOD1 HOUR This command reads the diode laser operating hours Diode laser operating hours are incremented every 6 minutes 0 1 hour that the diode laser is turned on Emission mode or in Standby mode Unit HrsD1 Example gt READ DIOD1 HOUR lt CR gt 234 8HrsD1 lt CR gt lt LF gt The diode laser has been operated for 234 8 hours READ DIOD1 TEMP This command reads the actual laser diode temperature in degrees C Unit degC Example gt READ DIOD1 TEMP lt CR gt 29 2degC lt CR gt lt LF gt READ FAULT This command reads the fault code refer to Table C 3 0 means there are no errors Example gt READ FAULT lt CR gt 12 CR LF The user interlock has been activated B 29 Explorer Actively Q Switched High Repetition Laser Systems READ FAULT HIST This command reads the history buffer which consists of up to 16 status codes activated after the most recent startup refer to Table C 3 Entries are separated by blanks Example gt READ FAULT HIST lt CR gt lt 0 12 24 13 12 23 24 25 12 lt CR gt lt LF gt
166. one or in combination with the serial commands Combining the two methods provides the greatest control over the laser output Both analog and serial controls are fully described in Chapter 7 Custom L Win control software for a Windows based personal computer is provided for operating the laser as a stand alone device for example when installing or servicing the unit Operating the Explorer using the L Win software is described in Chapter 6 Explorer systems are manufactured under one or more of the following patents 4 653 056 4 979 176 5 577 060 5 999 544 4 656 635 5 018 152 5 579 422 6 185 235 4 665 529 5 080 706 5 608 742 6 504 858 4 701 929 5 127 068 5 638 397 6 697 390 4 723 257 5 155 631 5 651 020 6 816 536 4 761 786 5 410 559 5 745 519 6 822 978 4 872 177 5 412 683 5 801 403 6 890 474 4 894 839 5 436 990 5 812 583 4 913 533 5 504 762 5 835 513 4 977 566 5 561 547 5 907 570 RE 34 192 Windows is a registered trademarks of the Microsoft Corporation 1 3 Explorer Actively Q Switched High Repetition Laser Systems Chapter 2 Laser Safety Danger Laser Radiation Eyewear S Required uw Spectra Physics Explorer lasers are Class IV High Power Lasers whose beams are by definition safety and fire hazards Take precautions to prevent accidental exposure to both direct and reflected beams Diffuse as well as specular beam reflections can cause severe eye or skin damage The ultraviolet beam at 355 nm is
167. ons to complete the software installation This procedure installs the L Win software and the LabView runtime libraries onto the computer hard drive After installation a new program group will be present in your Windows Start menu as Spectra Physics Laser Control gt L Win This manual as well as corrections and addenda will also be copied to your computer and will be accessible via the Windows Start menu The next sections describe how to set up communications between the computer and the laser system and how to start the laser for the first time LabView is a trademark of National Instruments Inc 5 5 Explorer Actively Q Switched High Repetition Laser Systems Setting Up Initial L Win Communications 1 Turn on the power supply 2 Start the L Win control software using your Windows Start menu 3 The software will automatically search for the COM port to which the L Series power supply is connected Alternatively you can select the port manually To do this refer to Appendix A for a description of the Tools menu under the Settings tab Turn On 1 Turn on the L Series power supply DC switch The POWER indicator on the power supply will illuminate Wait for the system to finish its initialization and warm up sequence which typically takes a few min utes During this time the red ERROR indicator on the power supply remains on When it turns off the laser is ready to operate Turn on the diode laser ON OFF keyswi
168. or expensive repairs be sure to read this chapter then carefully follow these instructions Chapter 3 Laser Description contains a more detailed description of the Explorer laser systems and concludes with system specifications and out line drawings Chapter 4 Controls Indicators and Connections describes the Explorer system components Chapter 5 Installation contains instructions for installing the system including hook up diagrams and lists of required components Chapter 6 Using the L Win Software provides instructions for using the custom graphic user interface to operate the Explorer laser as a stand alone system This chapter also provides further descriptions of the Explorer models along with some general considerations regarding laser output A complete listing of the commands available through the L Win interface is provided in Appendix A Chapter 7 Commands and Signals provides detailed instructions for using serial commands and analog signals to control the laser This chapter provides examples of different ways of configuring the laser output A compete listing of the serial command language is provided in Appendix B Chapter 8 Maintenance and Service is intended as a guide for routine maintenance as well as for troubleshooting the laser to identify the source of possible problems Do not attempt repairs yourself while the system is still under warranty Instead report all problems to Spect
169. osition dan gereuse de l oeil ou de la peau au rayonnement direct ou diffus Laser de classe 4 Puissance maxi mum moyenne de 1W 355 nm 4W 532 nm Energie maximum par impulsion 0 1 mJ 355 nm 1 mJ 532 nm Dur e d impulsion 5 20 ns Austritt von sichtba rer und unsichtbarer Laserstrahlung Bestrahlung vermei den Emissionskontrolle Sichtbare und oder unsichtbare Laser strahlung Bestrah lung von Auge oder Haut durch direkte oder Streustrahlung vermeiden Laser Klasse 4 Mittlere maximale Leistung1 W 355 nm 4W 532 nm Maximale Pulsener gie 0 1 mJ 355 nm 1 mJ 532 nm Pulsdauer 5 20 ns Por esta abertura se emite radiaci n l ser visible e invisible evite la exposici n Control de la emisi n Radiaci n l ser visi ble y o invisible Evi tar la exposici n directa dispersa sobre la piel o los ojos Producto L ser Clase 4 Potencia m xima promedio 1 W 355 nm 4W 532 nm Energ a m xima del pulso 0 1 mJ 355 nm 1 mJ 532 nm Duraci n de pulso 5 20 ns Vanuit dit apertuur wordt zichtbare en onzichtbare laser straling geemitteerd Vermijd blootstelling Controle van emissie Zichtbare en of onzichtbare laser straling Vermijd blootstelling aan ogen of huid door directe of gereflec teerd straling Klasse 4 laser pro dukt Maximaal uittredend vermogen 1 W 355 nm 4 W 532 nm Maximaal pulsener gie 0 1 mJ 355 nm 1 m
170. ot require a formal call or letter to our service or marketing departments but that you feel should be remedied We are always interested in improving our products and manuals and we appreciate all suggestions Send all instrument related questions to Send all manual related questions to Spectra Physics a Newport Corporation Brand Spectra Physics a Newport Corporation Brand Service Manager Senior Director Product Marketing 3635 Peterson Way 3635 Peterson Way Santa Clara CA 95054 Santa Clara CA 95054 FAX 408 980 3584 FAX 408 980 7101 Thank you From Name Company or Institution Department Address Instrument Model Number Serial Number Problem Suggested Solution s
171. ote that overriding the keyswitch reset does NOT comply with CDRH regulations Preset controls provide a means to store activate and boot the sys tem with a predefined parameter set In each panel click the menu but Explorer Actively Q Switched High Repetition Laser Systems Note Menu Bar Tools Menu ton to select the desired parameter set Factory 1 Factory 2 User 1 or User 2 then click OK to execute the function The factory sets cannot be changed but the user sets can be changed and stored again Activate Preset loads the specified parameter set from memory and activates it Store Preset stores the current actual system values as the spec ified parameter set User 1 or User 2 Boot with Preset designates the parameter set that will be acti vated the next time the laser system is turned on Activating a preset and storing the actual parameters as a preset are only possible when emission is turned off Depending on laser type the tools menu looks different For systems with average power measurement Figure A 9 there are no FPS Burst setup or Pulse Noise Measurement selections Terminal Status Bits Viewer Dump System Settings Set Output Power Energy Measurement Calibration Figure A 9 Tools Menu Average Power E L Win vi rev 505 Terminal Status Bits Viewer Pulse Noise Measurement FPS Burst Setup Dump System Settings Set Output
172. ounting baseplate Setting the Diode Pump Laser Temperature The laser diode operating temperature is specified between 18 35 C If the temperature is properly stabilized the measured value is constant in a range of 0 05 C To set the temperature of the diode laser in C enter the command DIOD1 TEMP lt f gt where f is a decimal number 18 0 lt f lt 35 0 Example DIOD1 TEMP 29 2 To read the temperature of the diode laser in C enter the query READ DIOD1 TEMP To read the temperature setting for the diode laser in C enter the query DIOD1 TEMP Setting the SHG and THG Crystal Temperatures Note g Warning m The Explorer models that produce output at 532 nm do not contain a THG crystal so only the SHG crystal temperature will be adjusted Temperatures are set in counts between 100 and 4000 for the SHG and THG crystals Do not change the temperatures of these components unless instructed to do so by an authorized Spectra Physics service representative Use the command CONT SHG TEMP lt n gt or CONT THG TEMP n to set the temperature of the SHG or THG crystal in counts Example CONT SHG TEMP 1650 Use the query READ SHG TEMP or READ THG TEMP to read the tempera ture of the SHG or THG crystal in counts Explorer Actively Q Switched High Repetition Laser Systems Example READ SHG TEMP 1649 Use the query CONT SHG TEMP or CONT THG TEMP to read the last com manded temp
173. pecifications for operating and non operating conditions are listed in Environmental Specifications on page v Model Part Number EXPL 355 300 EXPL 532 2W EXPL 532 200 General Characteristics Wavelength 355 nm 532 nm 532 nm Gain Medium Nd YVO Nd YVO Nd YAG Output power gt 300 mw gt 2W gt 2 W8 Pulse width FWHM lt 15 nsf lt 15 ns 15 ns Pulse Repetition rate 20 150 kHz 20 150 kHz single shot 60 kHz Leakage power 1064 nm 1mW 1mW 1mW 532 nm 1mW Beam Characteristics Spatial mode TEM go TEM go TEM oo Beam Quality M 1 3 1 3 12 Polarization Ratio Beam Waist Diameter gt 100 1 vertical 0 17 mm 15 100 1 horizontal 0 21 mm 10 gt 100 1 horizontal 0 20 mm 10 Waist Location 70 x20 mm 70 x20 mm 70 x20 mm Beam Divergence 3 0 0 5 mrad 3 5 0 5 mrad 3 5 0 5 mrad Beam Ellipticity lt 1 2 lt 1 2 1 2 Astigmatism lt 0 2 lt 0 2 lt 0 2 Stability Pulse energy stability lt A 4 lt 3 lt 39 5 Long term power stability non cumulative lt x296 1 hr 1 C lt x296 1 hr 1 C lt x296 1 hr 1 C Warm up time 10 min 10 min 10 min Static Alignment Tolerance Beam Position lt 0 25 mm lt 0 25 mm x 0 25 mm Beam Angle lt 1 mrad lt 1 mrad lt 1 mrad Due to our continuous product improvement program specifications may change without notice 2 Measured at 50 kHz 3 Measured at 1
174. petition Laser Systems Serial Communication Connection and Parameters The Explorer serial connection is the RS 232 port on the front of the power supply Refer to Table 4 1 on page 4 5 for a functional description of this connector Communications Parameters 4 800 57 600 baud No parity 8 data bits 1 stop bit Hardware handshake none Enable echo local typed characters Serial Command Query Language The user can issue commands and create programs for operating the Explorer laser system using the serial command query language described in Appendix B The latest version of the command language can always be obtained from Spectra Physics The command terminator is a carriage return lt CR gt All queries and com mands reply with a carriage return and line feed CR lt LF gt Commands are not case sensitive Serial Communication Through the L Win GUI Once installed in the host system a user written program run on the system host computer can be used to operate the Explorer possibly in combination with analog command signals Serial commands can also be entered manu ally through the RS 232 port using a terminal emulation program The L Win software provides a convenient method for executing serial commands Refer to Chapter 5 Installation for instructions on install ing and starting L Win From the L Win Main display select Tools from the menu bar then Terminal from the pull down list of options th
175. pled is shown by the pulses selection The data fields display the max value and min value for the energy values of the sampled pulses as well as their mean rms value and sigma in values The Clear button clears all data fields Gwn E Terminal Status Bits Viewer Pulse Noise Measurement trol Settings L Win S Energy Statistics FPS Burst Setup Display Access Dump System Settings S Spectra Physics L Win LASER CONTROL v 1 0 0 Emission Laser ID ID SPECTRA PHYSICS EXPLORER ON rasero PL0032 02 PS0031 01 3 14 A V3 20 81 OFF Standby Utilities Figure 6 4 Tools Menu Accessing the Energy Statistics Display 1 Only EXPL xxx yyy E models Operating Using the L Win Software Statistics tasso Pulses Jo1 23 mean 61 23 ms value max min meanj6 in 1 04 sigma in fiso D Oriine Histogram Histo Intervals 20 Or 1 1 1 1 1 58 000 59 000 60 000 61 000 62 000 63 000 64 000 Energy p3 Figure 6 5 Energy Statistics Display 6 7 Explorer Actively Q Switched High Repetition Laser Systems System Settings Calibrating the Pulse Energy Monitor Readings or Average Power Monitor Readings Swine Power Control Temp Control Settings Calibration Factor for the Pulse Energy or Calibration Settings pulse energy calibration Factor GUI op Average Power Readings Qa Start Emission without key switch reset Auto On Activate Pr
176. plied circuitry required to synchronized gating Main commands QSW PRF n n repetition rate Pin used 17 Method A Method B Operating with Commands and Signals Method B External pulse trigger external gating Advantage Easy set up no optical output power during off time fast rep etition rate changes optional synchronization Disadvantage Pulse clock has to be provided externally Main commands QSW PRF 0 external trigger mode Pins used 21 17 Pin 17 only enables or disables Q Switch trigger It has no impact on internal timing Method A gates the laser output on and off using an external gating TTL level signal applied to pin 17 The Q switch repetition rate is set internally using the serial command QSW PRF n Note that in this example the gate signal and the Q switch signal have no fixed timing with respect to each other i e the pulse to pulse time can vary between the gate open command and the first Q switch signal To keep the timing between gate open and the first Q switch signal constant use Method B This method is the same as Method A except that the Q switch is triggered by a TTL signal applied to pin 21 Another option is to use the Q Switch signal that is available on pin 19 to synchronize laser pulses with the gating signal on pin 17 Using the Q switch trigger as the output trigger allows laser pulses to be synchronized with the gating signal which is applied in the same fashion as in Method
177. plorer embedded controller and a customer control computer Range n 4800 9600 14400 19200 28800 38400 57600 bps bits per second Note At startup the system uses the last baud rate that was in effect B 2 Serial Commands and Queries Examples gt SYST COMM SER BAUD 14400 lt CR gt Set the actual baud rate to 14 400 bps gt SYST COMM SER BAUD CR lt 14400bps lt CR gt lt LF gt WDOG lt n gt WDOG This command sets the software watchdog alert time in seconds This is the watchdog timer for RS 232 communication between the embedded computer in the laser system and the host computer If the Explorer has not received commands from the customer s computer within the specified time the laser will turn off Unit sec Range n n 0 110 n 0 disables the watchdog timer default Values of 3 to 10 seconds would be typical Examples gt WDOG 10 lt CR gt Set the alert time to 10 seconds lt lt CR gt lt LF gt gt WDOG 0 lt CR gt Disable the software watchdog lt lt CR gt lt LF gt gt WDOG lt CR gt lt 0sec lt CR gt lt LF gt The software watchdog has been disabled Laser Operation These commands are executed only if the laser system has been put into Computer REMOTE mode with the command MODE RMT 1 or using the GUI ON This command turns the diode laser on The Explorer laser emission starts after a security delay of 3 seconds the emissio
178. prise a burst 1 Only EXPL xxx yyy E models 6 14 Note FPS Operation Note Operating Using the L Win Software To select Burst mode 1 Set the number of pulses to be contained in a single burst using the Pulses Burst field This setting together with the repetition rate will determine how long the burst will last The example shown in Figure 6 13 has 50 pulses at 50 kHz per burst so a burst will span 1 milliseconds 2 Use the Loop Time field to set in milliseconds how often a burst will be emitted Setting the delay to 200 ms as shown in Figure 6 13 will result in an interval of 200 ms between bursts in addition to the time the burst is emitted Note that Loop Time is a parameter only in L Win and is not supported by Explorer firmware or commands Clicking on the STOP button ends the Burst mode application Status shows its present status If the Burst mode application is exited with a non zero value set in the Pulses Burst field no laser light will be emitted until a new burst com mand is issued either by serial command or analog signal Setting Pulses Burst to 0 disables the Burst mode application First Pulse Suppression FPS is an important feature for operating the laser in Burst mode at high repetition rates Without FPS the first pulse of a burst of high repetition rate pulses will be a giant pulse with an energy much larger than the subsequent pulses With FPS the first pulse
179. r Source 6 10 To use an external trigger source instead of the Explorer internal Q switch trigger set the Repetition Rate Trigger switch to external The external trigger signal is input through the ANALOG IN connector on power supply Refer to The Analog Interface on page 7 15 and Basic Analog Operation on page 7 18 for information about operating the laser using analog signals Operating Using the L Win Software Component Temperature Adjustment Warning m To function properly the diode pump laser and the harmonic crystals in the laser head depend strongly on operating at their correct temperatures The temperatures of these components are controlled and stabilized using closed loop monitor driver circuits The Temp Control display provides controls for the pump diode and the second and third harmonic SHG and THG crystals depending on Explorer model The temperatures are set in C for the diode laser and in counts depending on Explorer model for the crystals Do not change the temperatures of these components unless instructed to do so by an authorized Spectra Physics service representative Setting the Diode Pump Laser Temperature Warning u Tools View a Power Control Temp Control Settings Diode Pu mp Laser Diode Temperature Temperature Control Diode T_set 27 00 ec T Diode 27 00 C S H G C ry st al SHG Crystal Temperature Temperature Control SHGT Se 2sso ds TSHG 2850 cts T
180. r a 3 sec ond safety delay Allow the laser to warm up and achieve stable out put The Explorer system comes with a data sheet that details the perfor mance of the laser before it left the factory Verify that the laser per forms at or close to the listed values by adjusting the current and repetition rate to match the listed settings Use a calibrated detector certified for use at the specified wavelength and pulsed output in the 100 kHz range to measure output power If you expect to use the laser again in a short while use the short term pro cedure below to leave the crystal ovens on in the laser head and thus reduce the warm up time Otherwise use the long term procedure Short term 1 On the L Win Power Control display click on the Emission button to turn off the laser 2 Leave the power supply keyswitch and power switch in the ON posi tion Long term 1 On the L Win Power Control display click on the Emission button to turn off the laser 2 Turn off the power supply keyswitch and power switch 3 Exit the L Win program and turn off the computer 5 7 Explorer Actively Q Switched High Repetition Laser Systems Chapter 6 Operating Using the L Win Software X Danger Spectra Physics Explorer lasers are Class IV High Power Lasers Laser Radiation whose beams are by definition safety and fire hazards Take precautions to prevent accidental exposure to both direct and reflected beams Diffuse
181. r occurred while com Reboot the system A COMM municating with the tempera If the problem persists contact ture controller responsible for Spectra Physics service the SHG THG control 1 ERROR TEMPCONTROLLER An error occurred while com Reboot the system B COMM municating with the tempera f the problem persists contact ture controller responsible for Spectra Physics service the diode laser control 2 ERROR DIODE1 The setpoint temperature for Contact Spectra Physics service TEMPCONTROL the diode laser cannot be adjusted by the control loop 3 ERROR SHG TEMPCONTROL The setpoint temperature for Contact Spectra Physics service the SHG crystal cannot be adjusted by the control loop 4 ERROR THG TEMPCONTROL The setpoint temperature for Contact Spectra Physics service the THG crystal cannot be adjusted by the control loop 5 ERROR DIODE1 PWM The temperature control loop Contact Spectra Physics service for the diode laser is operat ing at its limit 6 ERROR XTALS PWM The temperature control loop Contact Spectra Physics service for the SHG THG crystals is operating at its limit 7 ERROR DIODE1 PWM A diode temperature controller If the problem persists contact REBOOT reboot procedure took place Spectra Physics service 8 ERROR XTALS PWM REBOO A crystal temperature control If the problem persists contact T ler reboot procedure took Spectra Physics service place C 6 Operating Status Codes Table C
182. r ordering or shipping instructions or for assistance of any kind contact your nearest sales office or service center You will need your instrument model and serial numbers available when you call Service data or shipping instruc tions will be promptly supplied To order optional items or other system components or for general sales assistance dial 1 800 SPL LASER in the United States or 1 650 961 2550 from anywhere else This warranty supplements the warranty contained in the specific sales order In the event of a conflict between documents the terms and condi tions of the sales order shall prevail Unless otherwise specified all parts and assemblies manufactured by Spectra Physics are unconditionally warranted to be free of defects in workmanship and materials for a period of one year following delivery of the equipment to the F O B point Liability under this warranty is limited to repairing replacing or giving credit for the purchase price of any equipment that proves defective during the warranty period provided prior authorization for such return has been given by an authorized representative of Spectra Physics Spectra Physics will provide at its expense all parts and labor and one way return shipping of the defective part or instrument if required In warranty repaired or replaced equipment is warranted only for the remaining portion of the orig inal warranty period applicable to the repaired or replaced equipmen
183. ra Physics for warranty repair This chapter concludes with a list of world wide Spectra Physics service centers you can call if you need help Explorer Actively Q Switched High Repetition Laser Systems Should you experience any problems with any equipment purchased from Spectra Physics or if you are in need of technical information or support contact Spectra Physics Appendix A and Appendix B are references for the commands available through the L Win interface and the serial command language respec tively Appendix C lists all of the possible status codes that can be returned via system queries Appendix D contains a short section on laser theory regarding the laser crystal and the harmonic generation used in the Explorer as well as a brief description of some of the basic physics common to most lasers This product has been tested and found to conform to the provisions of Directive 73 23 EEC the low voltage directive governing product safety and the provisions of EMC Directive 89 336 EEC for electromagnetic compatibility Refer to the CE Declaration of Conformity statement in Chapter 2 Laser Safety for a complete list of test specifications Please note that the Explorer lasers are OEM systems that are designed to be inte grated into a master system that itself complies with regulatory require ments Every effort has been made to ensure that the information in this manual is accurate All information in this doc
184. rature for fan in control mode Voltage percent for fan in drive mode Analog port signal polarity Burst counts First Pulse Suppression delay time Alert time for software watchdog Auto on mode Computer Remote mode Sync pulse spanned over burst Table B 8 Global Parameters Command to Modify Parameter CONT SHG TEMP lt n gt CONT THG TEMP lt n gt CONT DIOD1 TEMP lt f gt DIOD1 CURR lt f gt or PCUR lt f gt QSW PRF n HEAD FANCON MODE lt n gt HEAD FANCON TEMP lt f gt HEAD FANCON PVOLT lt f gt CONFIG APORT POLAR n BURST CNTS n FPS DELAY n WDOG n MODE AUTOON n MODE RMT n BURST SYNC n Global parameters are stored if a user set is stored with the command CONFIG STOR lt n gt Parameter Description Pulse energy reference voltage counts Average power reference voltage counts Baud rate for serial communication Command to Modify Parameter PENER REFVOLT CNTS lt n gt POW REFVOLT CNTS lt n gt SYST COMM SER BAUD lt n gt User parameter set that is active at system start up CONFIG PARSET BOOT lt n gt Depends on Explorer model B 38 Serial Commands and Queries Table B 9 Serial Commands Command Access Restrictions o S S 3 9 R c o 8 5 E S 3 D 8 8 8 S F F s E S S 8 5 8 amp e 2 e o s Of E amp O S amp 3 8 8 8 28 8 8 8 8 9 8 ISSI 3 S S S SS 8 8 8 8 38
185. re 6 8 Selecting Analog Control or the Q Switch Trigger Source 00 0c eee eee 6 10 Figure 6 9 Temperature Control Display liliseeeesee RR mn 6 11 Figure 6 10 Selecting the GUI Mode 2 2 0 2 cece cette eee 6 12 Figure 6 11 Warning Entering Expert Mode 0 cece ee 6 12 Figure 6 12 Tools Menu 1 0 eh m mn 6 14 Figure 6 13 Burst Mode and FPS Display 0 00 c cece ne 6 14 Figure 6 14 FPS and Burst Mode Display llislleleeles en 6 16 Figure 7 1 Repetition Rate Correction l llilseselse nen 7 6 Figure 7 2 The 26 Socket ANALOG IN Connector 0 0 0 0 0 cece ee 7 15 Figure 7 3 Laser Control Circuit Example l llissessesee tte eee 7 18 Figure 7 4 Laser Indicator Circuit Example llllllselel tte ee 7 20 Figure 7 5 Pulse Energy Average Output Power Circuit 2l eres 7 21 Figure 7 6 External Sync Out and OptoSync Circuit 22i 7 21 Figure 7 7 Explorer Trigger Timing llsseeeeeeeee IRI II 7 22 Figure 7 8 Timing Diagrams for Methods A and B 0 cee eee 7 24 Figure 7 9 External Triggering with FPS and without Burst sussa saaa saaana aaa 7 25 Figure 7 10 External Triggering with FPS and Burst lilliilellsilel eee 7 26 Figure 8 1 Output Window Assembly 20 0c eee erre 8 4 xi Explorer Actively Q Switched High Repetition Laser Systems Figure 8 2 Loosen the top retaining Screw 0 0
186. re hazards Take precautions to prevent accidental exposure to both direct and reflected beams Diffuse as well as specular beam reflections can cause severe an eye or skin damage The ultraviolet beam at 355 nm is invisible and is Eyewear E therefore especially dangerous Residual light at 1064 nm 808 nm and Required 532 nm wavelengths might also be present Warning Never open the Explorer laser head To retain a clean intracavity envi IH ronment all components have been cleaned to stringent standards prior to assembly in a clean room and have been permanently aligned at the factory Removing the laser cover will compromise the cleanliness of the intracavity space and void the warranty There are no user service able parts inside the laser head replacement of the diode pump laser or the nonlinear crystals must be performed by a technician authorized by Spectra Physics to service Explorer systems Troubleshooting Any error that occurs will cause the ERROR indicator on the L Series power supply to turn on This troubleshooting guide is intended to assist in identifying some of the problems that might arise while using the laser Use the list of symptoms and potential problems on the following pages to trou bleshoot the laser system Procedures for performing the corrective actions for the symptoms listed in the service tables below are provided in the sec tion following the tables Note If a problem with the Explorer
187. roduction of individual pulses The OptoSync trigger is provided on Pin 14 of the ANALOG IN connector on the L Series power sup ply OptoSync triggering follows the laser pulse by about 30 to 100 ns depend ing on the pulse energy and pulse width For some applications this Opto Sync delay is unimportant Other applications may lend themselves to data collection techniques that compensate for this delay Refer to OptoSync on page 7 21 for more details regarding the use of these trigger outputs Burst mode allows the user to select a desired number of laser pulses to be grouped together as a single packet The number of pulses allowed in a burst is between 1 and 4095 Burst sequences can be controlled via soft ware commands or TTL signals The Explorer system also produces feed back signals for monitoring the status of individual burst sequences Figure 3 6 shows an example of Burst mode timing Refer to Advanced Control of the Pulsed Output on page 6 14 and Con trol of the Pulsed Output on page 7 12 for examples of how Burst mode can be implemented Start BURST MODE sequence Start BURST MODE sequence ht v v Standby Pin 15 LLLLLLA A LLELLA A Laser pulses Sync Out Pin 19 Burst feedback sequence completed Figure 3 6 Burst Mode Timing Example The Explorer Laser System First Pulse Suppression Users who operate high pulse repetition rate lasers greater than 20 kHz often have a problem when the first puls
188. rom but mathemati cally related to the color of the input beam This nonlinear optical effect is referred to as frequency conversion or harmonic generation It is com monly employed to change the infrared output of solid state lasers into a visible or ultraviolet beam Efficient harmonic generation requires power densities not typically avail able from a CW laser Since it is the instantaneous power of the fundamen tal beam that determines how much of the input is converted to the harmonic wavelength higher conversion efficiency can be achieved by concentrating the laser energy into pulses using techniques such as Q switching Frequency conversion requires that the fundamental and the harmonic light be phase matched That is the fundamental and the harmonic waves must remain in phase with each other inside the nonlinear crystal However since the two wavelengths are substantially different the fundamental and harmonic beams will experience dispersive effects resulting from different values for the index of refraction in the crystal This wavelength dispersion will cause the two beams to be quickly out of phase in the crystal unless special techniques are employed These tech Explorer Actively Q Switched High Repetition Laser Systems D 8 niques rely on the natural birefringence of the crystals used for frequency conversion Such crystals possess different refractive indices for different polarization states of the
189. rs 6 and 7 Diode pump laser has reached its end of Contact your Spectra Physics service representative life Symptom High optical noise Possible Causes Corrective Action Laser head temperature is outside the Verify that the laser head base plate is properly heatsinked operating range External noise source exists Check that there are no strong electromagnetic noise sources near the laser Laser is operating close to threshold sig Increase the diode laser pump current nificantly below specified values Frequency is too low or pump diode cur Increase the frequency or decrease the pump diode current rent is too high Symptom Bad transverse mode Possible Causes Corrective Action Laser is not warmed up Allow the laser to warm up for at least 5 minutes Output window is dirty Clean the laser head output window Laser head temperature is outside the Verify that the laser head base plate is properly heatsinked operating range Nonlinear crystals require temperature Refer to the section Setting the SHG and THG Temperatures in optimization Chapters 6 and 7 Nonlinear crystals have reached end of Contact your Spectra Physics service representative life Maintenance and Service Symptom Output power is unstable Possible Causes Corrective Action Loose cable connector Verify that all cables are securely connected Laser is not warmed up Allow the laser to warm up for at least 5 minutes Laser head
190. rst user parameter set User Set 1 Press the Find Diode Current button to send the command to the laser system The laser will search for the pump diode current required to achieve the desired output power pulse energy This may take 2 to 5 seconds The achieved power pulse energy and the required diode current will be displayed in the Measured block In the event this process was not successful an error message box will be displayed L Win GUI Reference Energy Power Measurement Calibration Sy DN Energy Measurement Calibration vi Energy Power Measurement Calibration Measured Power Pulse Energy External Internal Measurement Measurement Noise 1 sigma J 0 00 mi 824 50 mw 0 0 E ADC Reference Voltage PU Calibration Factor Old Value New Value Fixed 315 cts 315 cts 0 50 Figure A 14 Energy Power Measurement Calibration Display Use this tool to change the internal system calibration and therefore the power energy readout via both the RS 232 serial port and the analog port voltage calibration on Pin 1 Do not confuse this tool with the GUI calibra tion factor on the Settings tab which only calibrates the GUI power display External Measurement field allows the user to enter the measured output power pulse energy from an external calibrated meter After a value has been entered and the Set Calibration button is pressed a new calibration reference voltage will be calculated see below Internal Measurem
191. s Byte 2 1 tte eee C 1 Table C 2 Operating Status and Error Bits 0 0 0 0 0 cee C 2 Table C 3 Fault Codes sraa oi a e aA teens C 8 Table C 4 Non Critical Fault Codes 20 0 00 C 8 Table C 5 Laser Emission Shutdown Conditions siiis C 9 xii Warning Conventions The following warnings are used throughout this manual to draw your attention to situations or procedures that require extra attention They warn of hazards to your health damage to equipment sensitive procedures and exceptional circumstances All messages are set apart by a thin line above and below the text as shown here Danger Laser radiation is present Laser Radiation Danger Danger Warning Warning ESD Caution Don t Touch Eyewear Required V Y ly g A Condition or action may present a hazard to personal safety Condition or action may present an electrical hazard to personal safety Condition or action may cause damage to equipment Action may cause electrostatic discharge and cause damage to equip ment Condition or action may cause poor performance or error Text describes exceptional circumstances or makes a special refer ence Do not touch Appropriate laser safety eyewear should be worn during this opera tion Refer to the manual before operating or using this device xiii Standard Units The following units abbreviations and prefixes are used in t
192. s calc every x measurements control sets the update interval for calculating statistics in number of measurements max value field displays the highest measured energy value of the sampled pulses min value field displays the lowest measured energy value of the sampled pulses max mean mean 6 in field displays the value in percent of the difference between the largest pulse and the smallest divided by six times the average pulse level The first pulse is excluded from this cal culation Online Histogram control activates deactivates the data collection calculation and histogram display While this function is active the indicator illuminates and the displays are automatically updated Histo Intervals control sets the resolution of the histogram display in number of intervals to be used System Settings Summary G3 memory dump2 vi all xj diode set temp Courts S38cnts measured diode temp Counts 539cnts SHG set seeperakure 2200cnis SHG temperature 2199cnks THG set semperature 2710cnts measured dode temperature 20 05degC 3 Error History 30 25 24 23 13 List of active error codes 13 Serial command status 0 System status 0 Events status 2 Operational condition status 0 Parameter set status load storage 0 0 Access Level SERVICE amarres e air akin Farber Y PWIA Figure A 17 System Settings Summary A 17 Explorer Actively Q Switched High Repetitio
193. s of the active medium excited by the pumping source and the active medium occupied by the laser mode Maxi mizing this overlap is called mode matching and in most applications TEM is the laser mode that is most desired A longitudinal pumping geometry provides this optimal mode matching A Brief Review of Laser Theory Longitudinal pumping allows the diode laser output to be focused on a vol ume in the active medium that best matches the radius of the TEM mode In general the TEM mode is focused small as possible to maximize effi ciency Figure D 6 illustrates a mode matching design of this type Laser Diode Mode Volume TEMoo Mode Volume Gain Region Ns Lasing Medium Figure D 6 Mode Matching For higher output power levels a larger diode laser having a larger emis sion region is necessary The diameter of the TEM mode volume must also be expanded to effectively mode match the volume of the extended diode laser emission region Spectra Physics has developed an efficient method of coupling the output of the diode laser into the laser crystal where a fiber optic feeds the diode laser output into a telescopic combination of lenses that optimizes the pump beam for proper mode matching Harmonic Generation When an intense laser beam strikes a transparent crystal a new beam may be produced at an integer multiple of the frequency of the incident light that is a new beam is produced at a color different f
194. s the following sections Table B 1 Serial Commands and Queries grouped by function System Identification and General Setup Laser Operation Diode Current Diode and Crystal Temperature Control Q Switch Repetition Rate Pulse Counts and Operating Hours Analog Interface Pulse Energy Laser Power Data Administration Status and Error Reporting Power Saving Modes Laser Head Temperature Control First Pulse Suppression FPS Burst Mode Table B 2 Serial Commands and Queries listed alphabetically Table B 3 Ranges for Automatic Energy Power Adjustment Table B 4 Status Error Reporting Commands Table B 5 Analog Port Polarity Configuration Bits Table B 6 Analog Port Signal Status Bits Table B 7 User Parameters Table B 8 Global Parameters Table B 9 Serial Commands Command Access Restrictions No CNW a KRW WD N nunan nanna CONNUNWN CS Ww G2 9 GO G2 Go 9 m SMA 0o 1 10 Un Explorer Actively Q Switched High Repetition Laser Systems Table B 1 Serial Commands and Queries grouped by function System Identification and General Setup IDN This command returns the product identification string Returned is a four comma separated field manufacturer model serial number laser head power supply firmware version laser head power supply If the laser head controller is not communicating with the power supply controller the laser head firmware version is replaced by 999 Examples Typ
195. s the internally mea sured pulse energy in uJ low rep rate systems only Average Power bar and number field displays the internally mea sured average power in mW higher rep rate systems only System Status numeric and text fields display the system error status code and description The displays are updated once per second Refer to Table C 3 on page C 8 for status codes L Win GUI Reference Control Section Power Control Tab Display Tools View D Power Control Temp Control Settings ae G Spectra Physics L Win LASER CONTROL v 1 2 0 Emission Laser ID ID SPECTRA PHYSICS EXPLORER taser w 532 1000 100KP PV 0080 B62 ENG ON P5 0272 B02 ENG V4 00 330 100 4 00 111 OFF y Standby Utilities Control Pump Repetition Rate mode Current set RS A Trigger ana 34 00 A log 232 V internal external s measured current set 4 0 A Set actual iA f 50000 H 50000 Hz Figure A 4 Power Control Tab Display The Power Control tab display contains fields for controlling system func tions The display is updated once per second Laser ID field displays the laser identification string serial query IDN that is available after initialization Serial Port field provides a pull down menu for manually selecting the serial port of the control computer to which the L Series power supply is connected Note On most computer systems the serial ports will be named ASRLI INSTR ASRL2 INS
196. t This warranty does not apply to any instrument or component not manufac tured by Spectra Physics When products manufactured by others are included in Spectra Physics equipment the original manufacturer s war ranty is extended to Spectra Physics customers When products manufac tured by others are used in conjunction with Spectra Physics equipment this warranty is extended only to the equipment manufactured by Spectra Physics Notice Maintenance and Service This warranty also does not apply to equipment or components that upon inspection by Spectra Physics discloses to be defective or unworkable due to abuse mishandling misuse alteration negligence improper installa tion unauthorized modification damage in transit or other causes beyond the control of Spectra Physics This warranty is in lieu of all other warranties expressed or implied and does not cover incidental or consequential loss The above warranty is valid for units purchased and used in the United States only Products shipped outside the United States are subject to a watranty surcharge This laser product is intended to be sold to a manufacturer of electronic products for use as a component or replacement thereof in such electronic products As such this product is exempt from DHHS performance stan dards for laser products in accordance with paragraph 1040 10 a 1 or 2 Return of the Instrument for Repair Warning U Contact your nearest Spe
197. t CONT POW 5 20000 1 lt CR gt Request to set the laser power to 5 mW 20kHz lt lt CR gt lt LF gt Request is denied because 5 mW is outside the valid laser power adjustment range CONT POW This command reads the result of an automatic laser power energy adjustment Response lt f gt lt n gt determined diode current in Amps adjusted laser power in mW If the adjustment procedure failed the command returns Example gt CONT POW lt CR gt 1 93A 50mW lt CR gt lt LF B 22 Serial Commands and Queries CONT SHG TEMP n CONT SHG TEMP This command sets the SHG temperature in counts 100 lt n lt 4000 Unit cnts Examples gt CONT SHG TEMP 1650 lt CR gt lt lt CR gt lt LF gt gt CONT SHG TEMP lt CR gt 1650cnts lt CR gt lt LF gt CONT THG TEMP lt n gt CONT THG TEMP This command sets the THG temperature in counts 100 lt n x 4000 Unit cnts Examples gt CONT THG TEMP 2988 lt CR gt lt lt CR gt lt LF gt gt CONT THG TEMP lt CR gt 2988cnts lt CR gt lt LF gt DIOD1 CURR lt f gt DIOD1 CURR This command sets the diode laser current in Amps 0 lt f lt maximum diode laser current value in Amps i e the value returned by DIOD1 MAXC in the form xx xx Commands with values outside this range are rejected Examples gt DIOD1 CURR 4 56 lt CR gt Set the diode laser current to 4 56 Amps lt lt CR
198. t in an optical grating that has a period and amplitude set by the acoustic ultrasonic wavelength When a light beam is incident upon this grating a portion of its intensity is diffracted out of the beam Placing the AOM inside of a laser cavity pro duces a type of light switch that can either allow laser action to proceed or extinguish laser activity By choosing beam parameters properly any laser beam that attempts to cir culate within the resonator experiences a diffraction loss that is sufficient to prevent lasing i e there is no circulating beam The otherwise low loss high Q design of the resonator has been switched to a high loss low Q condition With no circulating laser light available to pass through the laser gain medium the pump energy boosts the gain in the crystal to a much higher level than would otherwise be present A long lifetime for the upper state laser level is beneficial to the Q switch process The ultrasonic wave is impressed on the AOM by a piezo electric trans ducer Switching off the driving voltage to the transducer returns the AOM to its passive state of high optical transmission and the laser resonator is returned to its high Q state Since the internal beam is no longer deflected and is instead amplified by the high gain now available in the laser rod a powerful Q switched laser pulse is emitted Voltage is then re applied to the AOM transducer which again spoils the cavity
199. t is replaced by the value of the next measured pulse This value is available via the RS 232 interface and the ANALOG IN port on the L Series power supply On lower repetition rate models the pulse energy monitor is an integral part of the Explorer s advanced control features These include the Opto Sync output Burst mode and First Pulse Suppression FPS features Burst mode FPS and OptoSync are described in more detail later in this chapter On higher repetition rate models these advanced pulse control features are also available but the user must measure the pulsed output externally in order to adjust FPS Information about using these features is provided in Chapters 6 and 7 which describe how to operate the Explorer laser Replaceable Output Window A problem common to all laser systems especially those that emit ultravi olet is the degrading effects caused by focusing intense light on the optical components within the system With this in mind the output window on the Explorer laser head is designed to be replaced in the field as needed to ensure the transmission and delivery of the full pulse energy output of the laser to the target Refer to Chapter 8 Maintenance and Service for instructions on when and how to change the window The output window on green Explorer models should not need to be replaced under normal circumstances Laser Head Thermal Management Thermal management of the Explorer laser head
200. t of 100 pulses BURST CNTS 0 Exit Burst mode and return to normal operation The Explorer laser allows the trigger output which is available for syn chronizing equipment to the laser output to be extended for the duration of the burst i e pin 19 External Sync is low for the whole duration of the pulse burst as shown in Figure 7 10 on page 7 26 BURST SYNC 1 extends the trigger output for the burst duration BURST SYNCO causes the trigger output to have its normal duration BURST SYNC returns the status of this synchronize over burst setting Figure 7 10 shows both trigger options Operating with Commands and Signals FPS Operation The first pulse of a burst will become anomalously large at high pulse rep etition rates This effect is discussed in more detail in Chapter 3 and also in Chapter 6 To reduce the energy in the first pulse use the First Pulse Suppression FPS commands and queries described below The query READ PENER HIST is useful for determining the level of the first pulse energy It returns the energy values of the first 50 pulses in counts after the ON BURST or READ PENER HIST command has been sent A returned value of 0 means the laser has not emitted a pulse in this session As an example a return might look like this 955 772 781 776 7716 TIS 173 Based on this example the FPS delay time should be set to reduce the first pulse from a value in counts of about 950 to about
201. tch 3 From the L Win Main menu select the Power Control tab Tools View D Power Control Temp Control Settings serial port TET Standby Control Pump mode Current set je n ana RS log d measured current set 4 0 Yo AP emission command error W system error std event operational status byte RS 232 comm error G Spectra Physics L Win LASER CONTROL v 1 2 0 SPECTRA PHYSICS EXPLORER 532 1000 100KP P 0080 B62 ENG PS 0272 B02 ENG 4 00 39Q 100 V4 00 111 Utilities Repetition Rate Trigger internal external Set actual 1j 50000 Hz 50000 Hz Average Power mW 1 1 1 j 822 500 1000 1500 2000 System Status No Error 0 Figure 5 4 The L Win Power Control Display 5 6 Turn Off Installation On the L Win Power Control display Control Mode should be set to RS 232 and Current set to A for Amps Set the Repetition Rate Trigger toggle switch to internal Verify that the laser beam is terminated properly For example point it into a beam block or power meter The laser will start either at the pre stored factory settings or the user stored pre set values Click on the Emission button to turn on the laser The blue EMISSION lamp on the power supply and the white indicator on the laser head will turn on indicating that the laser is capable of producing laser light The Explorer laser head will begin emitting laser pulses afte
202. temperature is outside Verify that the laser head base plate is properly heatsinked the operating range Nonlinear crystals require tempera Refer to the section Setting the SHG and THG Temperatures in ture optimization Chapters 6 and 7 Frequency is too low or pump diode Increase the frequency or decrease the pump diode current current is too high Corrective Procedures The L Series Power Supply From time to time check the air grills for dust build up and when neces sary vacuum out the dust Caution Do not blow the dust out with compressed air because this may simply force it into the power supply where it cannot be removed This is the only maintenance required for the power supply Removing and Cleaning the Output Window Danger Before removing the output window the laser must be off and the Laser Radiation keyswitch removed in order to prevent the laser from being turned on accidently during the procedure If a significant amount of scattered laser light appears around the laser beam the most likely cause is a contaminated output window If this is the case the output window must be removed from the laser head for cleaning Never try to clean the output window when it is mounted on the laser There is a second inner window behind the replaceable window that per manently seals the laser cavity Solvents used for cleaning the outer win dow while it is still on the laser might contaminate the inner windo
203. th the system status byte at the root Active conditions are illumi nated Individual conditions can be checked by branching from right to left to pinpoint the cause of an error Above each group of elements the serial command to retrieve the corresponding information is shown Explorer Actively Q Switched High Repetition Laser Systems Laser Serial Port field shows the active serial port for communica tion with the system Loop Time field sets the time interval to be used for automatic sta tus inquiries The default value is 3 seconds Access Level field displays the active access security level READ button issues a new query and updates the indicators QUIT button closes the window Set Output Power Energy A 12 DN Set Output Energy vi rev 11 Set Output Energy Set Values Repetition Store as Pulse Energy Frequency default 530 00 p3 jisoo00 Hz Q Measured Achieved Pulse Energy Diode Current 29 90 HJ 4 20 4 Figure A 13 Set Output Energy Display This tool uses the command CONT POW lt n gt lt n gt lt n3 gt or CONT PENER n 4 n5 nsa to set the average power or pulse energy output of the laser Refer to the command description in Appendix B To use this tool l 4 Enter the set points for power pulse energy and repetition frequency in the Set Values block Press the Store as default button if the new diode current setting is to be stored as the default for the fi
204. the laser head on the heat sink 1 Where XX is 0520 5 mm 10 1 m 20 2 m and 50 5 m xix Chapter 1 Introduction Figure 1 1 The Explorer Laser Head on left and L Series Power Supply Spectra Physics Explorer systems are solid state Q switched OEM lasers that produce superior quality ultraviolet or green output beams at adjust able repetition rates up to 150 kHz The Explorer lasers described in this manual are available at wavelengths of 355 nm or 532 nm These lasers are designed for applications where a high repetition rate low cost of owner ship and ease of integration are essential For each wavelength there are models with different ranges of adjustable repetition rates up to 60 kHz and up to 150 kHz The models in the lower range have an internal single pulse energy monitor while the higher repeti tion rate models have an internal average power meter The Explorer laser provides stable pulse energy through the entire range of its repetition rate as well as precise triggering or gating of pulsed output in response to user provided signals Changing the Explorer pulse energy or pulse repetition rate has little impact on the laser beam parameters An Explorer system consists of the Explorer laser head and an L Series power supply Figure 1 1 All versions of the Explorer offer a variety of methods for controlling laser output internal or external triggering or gat ing capability a unique trigger output that is hi
205. the output signal at pin 14 Figure 7 7 shows a timing chart OptoSync triggering follows the laser pulse by about 30 to 100 ns More information about OptoSync is provided in Chapter 3 The OptoSync output typically will not appear whenever the pulse energy falls below about 5 of specified power 7 21 Explorer Acti vely Q Switched High Repetition Laser Systems Danger Explorer pulse energy may be at levels that can cause serious skin or Laser Radiation eye damage even when below the threshold for OptoSync output Do not External Trigger IN Pin 21 External Sync OUT Pin 19 External Opto Sync OUT Pin 14 Laser Pulse Optical Out use the OptoSync trigger as a laser safety emission indicator General Timing Analog Port with External Trigger lt 1 max rep rate m gt gt 100 ns External Trigger inhibited H max 50 ns rae approx 50 ns approx 300 ns Figure 7 7 Explorer Trigger Timing Basic Operating Methods 7 22 This section describes two simple methods of operating the laser using ana log signals These methods are used to introduce the more sophisticated methods described later in this chapter Table 7 3 summarizes the two operating methods Table 7 3 Operating Mode Summary Method A Internal pulse trigger external gating Advantage Safe fast gating no optical output power during off time Disadvantage Additional user sup
206. the pulse energy to 10 uJ 50kHz The request was denied CR LF because 10 uJ is outside the valid laser pulse energy range CONT PENER This command reads the result of an automatic pulse energy adjustment Response lt f gt lt n gt determined diode current in Amps adjusted pulse energy in pJ If the adjustment procedure failed the command returns Example gt CONT PENER lt CR gt 1 93A1 200J CR LF Laser Power Commands related to laser power are valid for EXPL xxx yyy P models only READ POW This command reads the actual laser power in mW EXPL xxx yyy P models only Unit mW Example gt READ POW lt CR gt 500mW lt CR gt lt LF gt B 10 Serial Commands and Queries POW CALF This command reads the calibration factor which is used to convert the laser power ADC counts 0 1023 to the displayed milliwatt values The calibration factor is set at the factory Unit mW cnt Example gt POW CALF lt CR gt lt 0 044mW cnt lt CR gt lt LF gt POW REFVOLT CNTS lt n gt POW REFVOLT CNTS This command modifies the reference voltage of the laser power ADC It may be used to re calibrate the displayed power to match the values read at the user s power meter Higher reference voltage counts result in lower power values Range lt n gt 200 1023 Unit cnts Example gt POW REFVOLT CNTS 456 lt CR gt lt lt CR gt
207. tion of the intense fundamental beam is converted within a crystal or other nonlinear material to light at half the wavelength double the frequency This new light retains the coherent properties of the incident beam but has twice its frequency for Explorer systems the 1047 nm fundamental infrared beam produced by the Nd YLF crystal is converted to a new green beam at 524 nm This green beam is an intermediate stage for producing the ultraviolet output and it remains confined within the laser head The ultraviolet output is the third harmonic of the fundamental which is generated by mixing the infrared beam again with the second harmonic beam in a second nonlinear crystal Nonlinear frequency conversion then results in a new beam in the ultraviolet at 349 nm Note Frequency tri pling the fundamental beam to the ultraviolet directly using a single crystal is inefficient due to symmetry considerations that are part of the physics of nonlinear optical crystals A Brief Review of Laser Theory Acousto Optic Modulation and Q Switching An acousto optic modulator AOM is a block of fused silica that acts as an optical phase grating when vibrated by an ultrasonic wave A piezo electric transducer is used to impress an ultrasonic wave on the AOM The photo elastic effect describes how the strain field produced in the material by the ultrasonic wave changes the optical index of refraction in the block A standing wave of ultrasound will resul
208. tions to prevent accidental exposure to both direct and reflected beams Diffuse as well as specular beam reflections can cause severe eye or skin damage The ultraviolet beam at 355 nm is invisible and is therefore especially dangerous Residual light at 1064 nm 808 nm and 532 nm wavelengths might also be present When operated as a stand alone system for example before it is installed in a master system the Explorer laser can be conveniently controlled using the L Win software provided Chapter 6 provides instructions for operating the Explorer laser using the L Win software including instructions for monitoring performance chang ing the output power and controlling the pulsed output Appendix A con tains a complete description of each of the L Win GUI displays Installing the L Win Software The L Win software is provided on a CD ROM shipped in the accessory kit with the system If an earlier version of the L Win software is installed on the computer it should be upgraded to the version shipped with the laser system or to a newer version if software upgrades are provided by Spectra Physics Earlier versions may not be compatible with this laser system or they may not provide full functionality 1 Insert the CD into the computer to be used to control the system Use Windows Explorer or My Computer to find the CD drive then double click the file setup exe to start the installation 2 Follow the on screen instructi
209. to On feature Auto On mode overrides the need to turn the keyswitch off and on when using L Win Click on the button labeled Start Emission without key switch reset to enable Auto On Warning U Over riding the keyswitch does NOT comply with CDRH regulations 6 5 Explorer Actively Q Switched High Repetition Laser Systems Monitoring and Adjusting Performance The performance of the laser can be monitored from the Energy Statistics display and the performance can be optimized concurrently on the Main display Access the Energy Statistics display from Tools on the menu bar by selecting Pulse Noise Measurement from the drop down menu see Figure 6 4 and Figure 6 5 The Energy Statistics display monitors performance in terms of pulse to pulse stability by displaying the pulse energy distribution in a histogram as well as other statistical graphical representations Concurrently laser per formance can be adjusted using the Main display to change parameters such as diode laser current and pulse repetition rate Online Histogram activates deactivates the data collection calculation and histogram display While this function is active the indicator is on and the displays are automatically updated Histo Intervals sets the resolution of the histogram display in number of intervals to be used Statistics calc every x measurements sets the update interval for calculating statistics in number of measurements The number of pulses sam
210. to the internal EEPROM These settings can be manually stored by the user CONFIG PARSET STOR lt n gt This requires that the laser emission is disabled n 1 orn 2 The settings are automatically stored in the user set 1 or 2 respectively Note 1 The command is rejected if the laser is not switched on During the adjustment procedure queries about the diode current pulse repetition frequency and temperatures are not valid Note 2 During the adjustment procedure the status may be queried using the command STAT COND OPER and checking if bit 13 Power setting is activated CONT PENER 0 stops a launched adjustment procedure Examples gt CONT PENER 20 50000 1 lt CR gt Request to set the pulse energy to 20 uUJ 50kHz After completion the found parameters diode current are stored in the user parameter set 1 lt lt CR gt lt LF gt gt CONT PENER 10 50000 1 lt CR gt Request to set the pulse energy to 10 uJ 050kHz CR LF The request was denied because 10 uJ is outside the valid laser power adjustment range B 21 Explorer Actively Q Switched High Repetition Laser Systems CONT PENER This command reads the result of an automatic pulse energy adjustment Response lt f gt lt n gt determined diode current in Amps adjusted pulse energy in pJ If the adjustment procedure failed the command returns Example gt CONT PENER lt CR gt 1 93A1 200J CR LF
211. tor Label 1 Label 2 Label 3 DANGER INVISIBLE LASER RADIATION WHEN OPEN AND INTERLOCK DEFEATED AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION VORSICHT UNSICHTBARE LASERSTRAHLUNG WENN Newport Spectra Physics GmbH ABDECKUNG GEOFFNET UND SICHERHEITSVERRIEGELUNG BERBR CKT 14532 STAHNSDORF GERMANY BESTRAHLUNG VON M AUGE ODER HAUT DURCH DIREKTE ODER MODEL EXPLORER LASER SYSTEM STREUSTRAHLUNG VERMEIDEN LASER KLASSE 3B TYPE ICD 532 1W E DANGER RAYONNEMENT LASER INVISIBLE DANGEREUX EN CAS D OUVERTURE ET DATE MARCH 2008 LORSQUE LA SECURITEEST NEUTRALISEE EXPOSITION DANGEREUSE DE L OEIL S N PV 1234 62 OU DE LA PEAU AU RAYONNEMENT DIRECT OU DIFFUS THIS LASER PRODUCT COMPLIES WITH 21 CFR 1040 AS APPLICABLE MADE IN GERMANY A150 0125 Invisible Radiation CE Approval Danger Label 4 Label 5 VISIBLE AND OR INVISIBLE VISIBLE AND OR INVISIBLE LASER RADIATION LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION DIRECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT CLASS 4 LASER PRODUCT 355nm 532nm MAX AVERAGE POWER 1000mW MAX AVERAGE POWER 4000mW MAX PULSE ENERGY 0 1mJ MAX PULSE ENERGY 1mJ RESIDUAL WAVELENGTHS RESIDUAL WAVELENGTHS 532nm 808nm 1064nm lt 10mW 808nm 1064nm 10mW SEE MANUAL EN60825 1 2001 SEE MANUAL EN60825 1 2001 Class 4 CE Warning Label 7 TH
212. tor A 50 Q cable is recommended in order to maintain 50 Q termination is not necessary Delay wrt optical pulse 45 ns typical Jitter wrt optical pulse 1 ns typical the waveform 7 16 Table 7 2 ANALOG IN Pin Description Operating with Commands and Signals Pin Type Description Function 15 Input Digital STANDBY Internal pull up Pull low high to force the laser diode into standby current level e g it blanks laser output Timing 2nd order lag Delay time 5096 5 us typ Rise time 5 us 20 80 typ 16 N A Do not connect 17 Input Digital EXT GATE Internal pull up Pull low high to gate the pulse trigger blanks laser output 18 Input Digital ILD SOURCE Internal pull up Pull low high to switch to an external current control use EXT pin to set the diode current 19 Output Digital SYNC OUT TTL evel pulse that is synchronous with the leading edge of the trigger see Figure 7 7 for timing Source HCT gate 5 V 50 Q series resistor A 50 Q cable is recommended in order to maintain the waveform 50 termination is not necessary 20 N A Do not connect 21 Input Digital EXT TRIG Internal pull up Generates a single Q switch pulse TTL level Software must be set to external triggering mode QSW PRF 0 to enable this pin 22 Analog reference AGND Ground for Pins 1 and 2 23 N A Do not connect 24 Digital reference DGND Ground for Pins 9 10 11 13
213. ts the terminal emulation program closes the win dow and deactivates the serial communication link Command String field allows the operator to enter serial com mands and queries Send button sends the entered command or query to the power sup ply System Answer field displays a log of the system responses to the sent commands or queries Status Bits Viewer SiL win_Status_Bytes vi STATus CONDition SYSTem PARameterSET ERROR LOAD PS GLEL ERROR LOAD PS USER ERROR LOAD PS HISTORY ERROR LOAD HEAD GLEL ERROR LOAD HEAD USER ERROR LOAD HEAD HISTORY ERROR STORE PS GLBL ERROR STORE PS USER ERROR STORE PS HISTORY ERROR STORE HEAD GLBL ERROR STORE HEAD USER ERROR STORE HEAD HISTORY ERROR STORE LICENCE ERROR LOAD LICENCE STATus CONDition SYSTem HEAD ERROR COMMUNICATION E EC46 ERROR CONFIGURATION WE EC46 ERROR PCB OVERTEMP WE EC34 39 ERROR RFPOWER Sill ERROR HEATSINK OVERTEMP E EC34 39 ERROR QSWITCH TIMING E ERROR HEATSINK UNDERTEMP E EC37 STATus CONDition SYSTem TCONT ERROR TEMPCONTROLLER COMM EE ERROR TEMPCONTROLLER B COMM ill ERROR DIODE1 TEMPCONTROL E EC23 ERROR SHG TEMPCONTROL WE EC24 ERROR THG TEMPCONTROL W EC25 ERROR DIODEi PWM EE EC23 ERROR XTAL PWM EN EC24 25 ERROR DIODEi PWM REBOOT T ERROR XTALS PWM REBOOT ill STATus CONDition SYSTem DIODe1 ERROR CABLE TW EC31 ERROR CURRENT W EC32 STATus CONDition SYSTem AnalogPOR T WARNING MISSING
214. tween the power supply and laser head Contact Spectra Physics service Check the cable connection between the power supply and laser head Contact Spectra Physics service Make sure the laser head is properly heatsinked If the problem persists contact Spectra Physics service Contact Spectra Physics service Make sure the laser head is properly heatsinked Contact Spectra Physics service No action is required Explorer Actively Q Switched High Repetition Laser Systems Table C 2 Operating Status and Error Bits Continued Bit M x Active Description Condition Action Required 7 ERROR INVALID MODEL The internal model setting Contact Spectra Physics service does not match the installed software 8 ERROR LASERHEAD The laser head was not Turn the laser system off Check NOT CONNECTED detected by the software the cable connections between the power supply and the laser head Turn the laser system on again System Condition POWER SUPPLY Register Query STAT COND SYST PSUPPLY 0 ERROR PS PCB OVERTEMP The laser turned off because Contact Spectra Physics service the maximum temperature of the main PCB was exceeded 1 ERROR DIGCONT PCB The laser turned off because Contact Spectra Physics service OVERTEMP the maximum temperature of the digital controller PCB was exceeded System Condition TEMPERATURE CONTROLLER Register Query STAT COND SYST TCONT 0 ERROR TEMPCONTROLLER An erro
215. ument is subject to change without notice Spectra Physics makes no representation or warranty either express or implied with respect to this document In no event will Spectra Physics be liable for any direct indirect special incidental or consequential damages resulting from any defects in this documentation Finally if you encounter any difficulty with the content or style of this manual or encounter problems with the laser itself please let us know The last page of this manual is a form to aid in bringing such problems to our attention Thank you for your purchase of Spectra Physics instruments CE Environmental Specifications CE Electrical Equipment Requirements For information regarding the equipment needed to provide the electrical service listed in Table 3 2 please refer to specification EN 309 Plug Outlet and Socket Couplers for Industrial Uses listed in the official Jour nal of the European Communities Environmental Specifications FCC Regulations Explorer systems are designed for indoor use The environmental condi tions under which these laser systems will function are Operating specifications Altitude 0 to 2000 m Temperature 18 C to 35 C Max Baseplate Temperature 40 C Relative humidity lt 80 non condensing Mains supply voltage not to exceed 10 of the nominal voltage Insulation category II Pollution degree 2 Non operating specifications Altitude 0 to 12000 m Temperature
216. upply key switch is in the ON position gt MODE RMT 0 lt CR gt Places the system in Local analog mode and the laser is turned on by turning the key switch to the ON position or by processing the EXTERNAL_DIODE_ON line of the analog interface gt MODE RMT lt CR gt Queries the setting for the Remote mode MODE SLEEP lt n gt MODE SLEEP This command activates deactivates Sleep mode In Sleep mode the Q switch and the TECs for controlling the temperatures of the harmonic crystals and diode laser are turned off Range lt n gt n 1 Sleep mode on n 0 Sleep mode off Note in Sleep mode all commands besides status queries are rejected Examples gt MODE SLEEP 1 lt CR gt Activate Sleep mode lt lt CR gt lt LF gt gt MODE SLEEP lt CR gt 1 CR LF B 26 Serial Commands and Queries MODE STBY lt n gt MODE STBY This command enables disables the Standby mode for the diode laser refer to Setting the Laser to Standby Modes in Chapter 7 for a description of Standby mode Range lt n gt n 1 enable standby mode n 0 disable standby mode and turn laser on again if previously switched on OFF This command turns the diode laser off ON This command turns the diode laser on The Explorer laser emission starts after a security delay of 3 seconds the emission indicator turns on immediately PCUR lt f gt PCUR This command sets th
217. ure by the than the laser head temperature set point 7 11 Explorer Actively Q Switched High Repetition Laser Systems Control of the Pulsed Output Burst Control 7 12 The BURST command causes the Explorer laser to emit one burst of pulses The number of pulses in a burst is set using the command BURST CNTS n where n is a decimal number 1 lt n x 4000 The command BURST CNTS 0 disables Burst mode and returns the laser to normal output Burst mode can only be initiated using serial commands However bursts can be started using analog signals applied to the ANALOG IN port To return the number of pulses that will be contained in the next burst when issued use the query BURST CNTS If the return value for this query is 0 Burst mode is disabled The following is an example of how to execute a burst output Laser emis sion is assumed to be off Note if the laser was booted using pre set param eters or is already operating at the desired energy level and pulse repetition rate the first 3 commands should be skipped MODE RMT 1 Place the laser in computer control QSW PRF 50000 Set the pulse repetition rate In this example 50 kHz DIOD1 CURR 4 0 Set diode current BURST CNT 100 Select the number of pulses in the burst In this example 100 pulses ON Emission is activated 3 sec safety delay No pulses are emitted laser emission is at idle BURST Emit a burst of 100 pulses BURST Emit a second burs
218. vi Laser Serial Port Pulse Energy Waveform Graph L 4 i istPuse E Pulses Burst i Other Pulses MUNI 4 1st Pulse z 1st Pulse r Error in FPS Delay Time 1st Pulse Error in 96 Pulses 2nd to End Mean A H i J 1 1 Uu Uu Uu i 1 1 1 Sigma in qu 10 15 20 25 30 35 40 45 50 55 Pulses G Displ oo 5 Status Burst done Figure 6 14 FPS and Burst Mode Display The energy of the first pulse can be compared to the remaining pulses using the red bar shown in the waveform graph Also the First Pulse Error field displays the discrepancy as a percentage between the energy of the first pulse and the mean energy of the remaining burst pulses Adjust the FPS Delay Time value until the First Pulse Error is close to 0 This display provides additional pulse energy monitoring as well The First Pulse field displays the energy of the first pulse of the burst The Pulse energy field displays the energy of a burst chronologically The Pulses 2nd to end mean field displays the calculated average energy of the first 50 pulses in a burst except the first And the sigma in field displays the cal culated standard deviation of the energy of all pulses in the burst exclud ing the first pulse The Waveform Graph display shows one vertical bar for each pulse in a burst showing its energy in relation to other pulses Use the Graph Display button to display or not display the waveform graph 6 16 Operating Using the L W
219. w and thus destroy the laser Always remove the outer window for inspection or cleaning Note that the inner window cannot be cleaned Do not allow any dust or other contaminants to enter the space between the windows 8 3 Explorer Actively Q Switched High Repetition Laser Systems Warning m Observe the following when removing the output window e The output window assembly should only be removed in a clean dust free environment All tools parts and solvents should be gath ered first to minimize the time that the window is removed from the laser e Always wear clean room gloves when exchanging or handling the output window Never touch the window itself even with gloves on handle the window assembly only by its rim mount Tools required e gloves 2mm Allen key e tweezers Top Retaining Screw Output Window Window Rim Mount Bottom Retaining Screw Figure 8 1 Output Window Assembly Maintenance and Service Procedure 1 Loosen the top retaining screw while carefully pressing against the rim mount to hold the window assembly in place Figure 8 2 Do not remove the screw completely Figure 8 2 Loosen the top retaining screw 2 While still holding the rim mount carefully loosen the bottom screw until the window assembly is completely free Figure 8 3 Figure 8 3 Loosen the bottom retaining screw Do not remove either retaining screw completely Reassembling the window is much easi
220. wer level whose energy content is E to a higher one with energy It will only occur if the energy of the incident photon matches the energy difference between levels i e where h is Planck s constant and vis the frequency of the photon Light will be used to describe the portion of the electromagnetic spectrum from far infrared to ultraviolet Explorer Actively Q Switched High Repetition Laser Systems Figure D 1 Electrons occupy distinct orbitals that are defined as the probability of finding an electron at a given position The shape of the orbital is determined by the radial and angular dependence of this probability Likewise when an atom excited to E decays to E it loses energy equal to E E The atom may decay spontaneously emitting a photon with energy hv and frequency v 2 Spontaneous decay can also occur without emission of a photon the lost energy taking another form e g transfer of kinetic energy by collision with another atom An atom excited to E can also be stimulated to decay to E by interacting with a photon of frequency v emitting energy in the form of a pair of photons that are identical to the incident one in phase fre quency and direction This is known as stimulated emission By contrast spontaneous emission produces photons that have no directional or phase relationship with one another A laser is designed to use absorption and both spontaneous and stimulated emission to creat
221. witched High Repetition Laser Systems Selecting Analog Control ome Tools View D Power Control Temp Control Settings ee d G Spectra Physics L Win ASER CONTROL v 1 2 0 Emission Laser ID ID SPECTRA PHYSICS EXPLORER 1sser 0 532 1000 100KP PV 0080 B62 ENG ON PS 0272 B02 ENG V4 00 39Q100 C V4 00 111 OFF Standby Utilities Internal External Trigger Modes Control Pump Repetition Rate 4 acc i ial M se die eratin odes d 400 A P g At J internal gt external measured current set 40 A Set o 4 actual A i 50000 Hz 50000 Hz Figure 6 8 Selecting Analog Control or the Q Switch Trigger Source Setting the analog RS 232 toggle switch to analog in the Control Mode section under the Power Control tab allows the laser to be controlled via analog volt ages applied to the ANALOG IN connector While in this mode the controls for emission on off are disabled on the L Win displays Refer to The Ana log Interface on page 7 15 and Basic Analog Operation on page 7 18 in for information about operating the laser using analog signals When Control Mode is set to RS 232 the laser can be controlled via the L Win displays and likewise through serial commands Refer to Basic Serial Operating Control on page 7 3 for information about operating the laser using the RS 232 serial commands Also refer to Appendix B for a detailed description of the RS 232 commands Changing the Q Switch Trigge
222. y Q Switched High Repetition Laser Systems Upon selecting GUI Mode a dialog box with a warning message appears Figure A 7 gt Switch GUI Mode vi rev 3 xi Expert Mode Do not activate Expert Mode if you are not absolutely sure that you know and understand what you are doing Changing settings in Expert Mode may result in serious changes of system performance or may even permanently damage the system Figure A 7 Warning Entering Expert Mode To enter Expert mode click on the EXPERT MODE button it turns red and confirm by clicking on OK The temperature controls are now activated To return to Standard mode select View GUI Mode again and click on the EXPERT MODE button once more it turns black or restart the L Win soft ware Before changing the diode laser temperature record the present values for operating current and temperature as well as the other laser parameters output power etc in the event they need to be restored later To maintain the diode laser wavelength at its optimum value of 808 nm make small adjustments to the diode laser temperature in maximum increments of 10 counts then wait a few seconds to see the effect the change has on pulse energy or average power before continuing Set the desired temperature of the pump diode using the Diode T set con trols The T Diode field displays the measured temperature in C If the ini tial operating parameters are lost restore the ori
223. y low threshold for lasing due to its very large absorp tion cross section for the diode pump wavelength It has rapid optical response which enables high frequency Q switching Vanadate s natural birefringence avoids the depolarization problems of isotropic crystals like Nd YAG which can cause difficulties for harmonic generation Vanadate accepts high doping of neodymium which is an important con sideration for end pumping by a diode laser source Diode Pumped Laser Design A diode laser combines high brightness high efficiency monochromaticity and compact size in an ideal source for pumping solid state lasers Figure D 5 shows the emission spectra of a diode laser compared to a krypton arc lamp and compares that with the absorption spectra of the Nd ion The near perfect overlap of the diode laser output with the absorption band ensures that the pump light is efficiently coupled into the laser crystal It also reduces thermal loading since any pump light not coupled into the medium is ultimately removed as heat Weven um Laser Diode Pump Wavelength _ Krypton Arc 7 Lamp 0 6 Nd3 Absorption A 0 6 oL a o Emission Intensity o a Wavelength uum Figure D 5 Nd absorption spectra compared to emission of a Kryp ton Arc Lamp a and a Diode Laser Pump b One of the key elements in optimizing the efficiency of a solid state laser is maximizing the overlap of the region
224. y the measured current Both values are displayed either in Amperes or in percent of the maximum current drive setting depend ing on Current set switch setting Current can be set by using the up down arrows or by typing in the desired value in the window Repetition Rate Trigger control sets the Q switch trigger mode to internal or external TTL low on pin 21 of the ANALOG IN port Repetition Rate Set Actual fields sets the pulse repetition fre quency and displays the measured frequency when Internal Trigger mode is selected Temperature Control Tab Display ome Tools View Power Control Temp Control settings Diode Pu mp Laser Diode Temperature Temperature Control Diode T set 27 00 ec T Diode 127 00 C SHG Crystal Temperature SHG Crystal Temperature Control J 2850 cts TSHG 2850 cts THG Crystal Temperature THG Crystal Temperature Control Diode Hours 2 7 Pulse Count Mcts 311 Figure A 5 Temperature Control Tab Display A 4 L Win GUI Reference The Temp Control tab display provides controls for setting the temperature of the pump diode and the second and third harmonic generator crystals SHG and THG The temperatures are set in C for the diode laser and in counts for the SHG and THG If the temperatures are properly stabilized the measured values are constantly in a range of 0 05 C and 3 counts respectively Depending on laser model the THG crysta

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