PulseScout Autocorrelator
Contents
1. 3 1 Menu Structure Overview clio ae 9 3 2 Control Menus u Rei 11 32 1 Main Men sereni lee 11 3 2 2 Correlator Submenus eee seen n nenne 12 3 23 Other S bmenus see lan 17 4 Installation 21 4 Detector and Crystal Installation eee 21 4 1 1 Crystal Exchanee an teret dtd 22 4 1 2 Detector Exchange oreet ai 23 42 Interconnect Cables eee taies equites possi seinen 24 23 Inpgtos Teniente ea eee rede etl aec ia aene 24 4 3 1 Baseplate Attachment 24 4 3 2 Input Laser Beam Alignment see 25 4 4 Collinear Autcorrelation essen 26 4 5 Finding the Autocorrelation Trace sse 26 4 6 Non Collinear Autocorrelation esee 27 Preface 5 Operation 3 1 Basic Operationen erneute 5 2 Scan Range Variation Duy ZERO SCAN Are 3 4 Low Pass 5 5 Interference Modulation sssssss 5 6 Calculation of the ACF Half Width 6 Troubleshooting 6 1 Rotation of Plane of Polarization 6 2 Fundamental Overload 6 3 Common Errors sauna 6 3 1 No SHG Signal entes eet 6 3 2 Input Power Too Small 6 5 3 No Clear ACE 2 arg 7 Safety 8 Factory Service Information 8 1 Service Form AR2. EN 61010 1 2001 2 Edition Safety requirements for electrical equipment for measurement control and laboratory use P Lf 7 sor Bruno Rety Dan Dunahay Group Director of PPT Instrument and Motion Europe Director of Quality Systems Micro Controle Division of Newport Corporation Newport Corporation Zone Industrielle 1791 Deere Avenue 45340 Beaune la Rolande France Irvine Ca 92606 USA Preface Technical Support Contacts North America amp Asia Europe Newport Corporation Service Dept Newport MICRO CONTROLE S A 1791 Deere Ave Irvine CA 92606 Zone Industrielle Telephone 949 253 1694 45340 Beaune la Rolande FRANCE Telephone 800 222 6440 x31694 Telephone 33 02 38 40 51 56 Asia Newport Opto Electronics Technologies 253 Aidu Road Bld 3 Fir 3 Sec C Shanghai 200131 China Telephone 86 21 5046 2300 Fax 86 21 5046 2323 Newport Corporation Calling Procedure If there are any defects in material or workmanship or a failure to meet specifications promptly notify Newport s Returns Department by calling 1 800 222 6440 or by visiting our website at www newport com returns within the warranty period to obtain a Return Material Authorization Number RMA Return the product to Newport Corporation freight prepaid clearly marked with the RMA and we will either repair or replace it at our discretion Newport is not responsible for damage occurring in transit and is not obligated to accept products returned wi
3. fitness for a particular use Newport Corporation shall not be liable for any indirect special or consequential damages resulting from the purchase or use of its products First printing 2007 2007 by Newport Corporation All rights reserved No part of this manual may be reproduced or copied without the prior written approval of Newport Corporation This manual has been provided for information only and product specifications are subject to change without notice Any change will be reflected in future printings Newport Corporation 1791 Deere Avenue Irvine CA 92606 USA P N 90002247 Rev A Preface iii EU Declaration of Conformity We declare that the accompanying product identified with the ce mark complies with requirements of the Electromagnetic Compatibility Directive 89 336 EEC and the Low Voltage Directive 73 23 EEC Model Number PScout Series Autocorrelator and all options Year C mark affixed 2007 Type of Equipment Electrical equipment for measurement control and laboratory use Standards Applied Compliance was demonstrated to the following standards to the extent applicable EN 50082 1 Electromagnetic compatibility Generic immunity standard Part 1 Residential commercial and light industry EN 55011 Radio Frequency Disturbance Industrial scientific and medical ISM radio frequency equipment Radio disturbance characteristics Limits and methods of measurement IEC CISPR B 269 CDV
4. lights or block off the source of external light to the autocorrelator Rotate the crystal by using the Turning knobs to find the optimal angle An optimally aligned crystal is characterized by a clear angle dependent signal maximum The actual angle value for the crystal is shown in the lower right corner of the display If a limit is reached such that the numbered displayed is no longer changing reverse the drive direction Attention Many laser sources have a small portion of second harmonic light coincident with the fundamental laser pulse and this small amount of light may swamp the second harmonic signal that is generated by the thin crystal inside the autocorrelator To avoid this insert a long pass filter into the laser beam such that the fundamental wavelength is transmitted and wavelengths in the vicinity ofthe second harmonic are blocked Installation 27 4 6 As a check for the real autocorrelation signal block one of the beams of the Michelson Interferometer inside the autocorrelator This can be done by pushing the knobs on top of the autocorrelator Blocking either beam individually will eliminate the signal originating from the interaction of the two beams In addition it will reduce the background away from the peak by 50 Optimize the peak and the peak to background ratio of the autocorrelation signal through adjustment of the crystal tilt focus scan range and filter If there is no angle dependent
5. may require reoptimization Scan Range Variation Each scan range is measured by a delay sensor stabilized and calibrated The delay output is normalized to appr 0 10V amplitude After switching to another scan range it takes some time 5 30 s to reach the new range ZERO Scan The ZERO SCAN function stops the delay at the zero position At the display the signal values at different times are shown similar to an oscillograph It is thereby possible to observe amplitude modulations and to align the autocorrelator to the maximum of the ACF 29 30 Operation 5 4 5 5 5 6 Low Pass Filter This switchable filter suppresses high frequency noise of the detector or the interference fringes in the collinear case For the measurement in triggered mode and of a fringe resolved ACF it is automatically switched off Interference Modulation If exactly aligned in the collinear case the AF is superimposed by the interference fringes of the interferometer sinusoidal modulation fringe resolved ACF They can either be averaged with the low pass filter simple intensity ACF or displayed with the FRINGES mode displaying the envelope of this function This mode helps to check if the pulse is chirped In the triggered mode where this filter is not active and in the ZERO SCAN the fringes simulate strong amplitude modulations which make it difficult to align the optimal phase matching Therefore it is recommended to increa
6. signal or no peak check that there is no stray light from the laser beam by inserting a long pass filter into the beam Additionally go back and recheck the alignment so that there is a back reflection at the cross wires that the input polarization is horizontal and that the laser is mode locked see chapter 7 1 Troubleshooting If the autocorrelation signal goes off scale decrease the GAIN and or decrease the laser input power ND filters lower reflectivity of the coupling element etc Non Collinear Autocorrelation Set the instrument to the collinear autocorrelation mode Gradually move from the collinear configuration to the non collinear configuration By turning the Beam Distance screw see fig 1 a configuration between collinear and non collinear can be chosen The beam separation distance can be monitored directly at the control window In the non collinear case the second movable back reflection will be to the left side of the cross hairs While changing the beam distance make sure to optimize the focus adjustment the sensitivity and the phase matching angle 5 1 5 2 5 3 Operation Basic Operation 1 Switch on the autocorrelator and wait for the instrument to finish its initialization regimen 2 Check the alignment 3 Read the autocorrelation trace 4 Remember if the wavelength is changed the phase matching angle will need to be changed In addition the GAIN and focusing adjustment
7. to be untightened This can be achieved by using the foot clamps as a wrench Attach the baseplate to the optical assembly level the unit and lock down the adjustment feet 1 Screw the two front feet into the base plate as shown in Figure 16 2 Place the optical unit onto the baseplate aligning the hole underneath the control window with the pin in the baseplate 3 Using the M6 screw provided attach the optical unit to the base plate 4 Level the base plate to the appropriate height Installation 25 is E gt TR Y N 2 Le 9 j __ N alt N Se N l Ten base plate counter nut screw leg foot foot clamp E 1 4 3 2 Fig 16 Adjustment Feet Input Laser Beam Alignment Direct a portion of the laser beam towards the autocorrelator using an appropriate optical element glass plate mirror etc mounted in a good mirror mount The beam should enter through the input aperture of the autocorrelator nearly perpendicular to the unit The input beam must have horizontal polarization in order to satisfy the phasematch condition of the nonlinear crystal and have low angular divergence Bring the back reflection of the beam to match the cross wires at the control window by alignment of the optical unit If there are two back reflections noncollinear interaction they can be united by turning the screw see fig 1 26 Installation 4 4 4 5 Twisting the optical assem
8. 800 222 6440 Tel 949 863 3144 Fax 949 253 1680 Internet sales newport com Visit Newport Online at www newport com BSI Newport Corporation Irvine California has been certified compliant with ISO 9001 by the British Standards Institution ISO 9001 FM 27207 Printed in the U S
9. EA 1 General Information 1 1 Introduction The PulseScout autocorrelator consists of two components the optics module shown in fig 1 and the control electronics shown in fig 2a and fig 2b The optics module contains a Michelson interferometer the delay unit the interaction unit SHG unit and the detector head The control electronics contain the necessary drivers and amplifiers the display and the power supply Crystal exchange lid Shutter Fixing screws Detector module Input laser beam Connection to control electronics Collinear non collinear mode Fig 1 Optics Module General Information The front panel of the control unit is shown in fig 2a There is a power switch and the push buttons for controlling the cursors lt CURSOR gt the phase matching angle TUNING the scan ranges SCAN RANGE The front panel also includes a MAIN and RETURN buttons for navigating the menu tree MAIN takes you to the Main Menu while RETURN takes you back one level in the Menu Structure Additionally includes 6 soft keys at the right edge of the display The function of these keys depends on what menu you are in Please refer to Chapter 3 for menu details A GAIN tuning knob is located in the lower right corner of the front panel Fig 2a Control Electronics Front Panel General Information 3 Fig 2b Control Electronics Rear Panel At the rear panel of the control e
10. IEW PulseScout Labview Driver RS232 3 1 Menu Structure Menu Structure Overview The scan range SCAN RANGE the gain GAIN the phase matching angle TUNING and the cursors lt CURSOR gt are controlled directly with the corresponding elements on the front panel see fig 2 The TRIGGER input BNC connector is used to apply the trigger signal from the laser necessary for an operation in the sampling mode All other functions are menu controlled Fig 4 shows an overview of the whole menu structure which is controlled by 6 soft keys at the right side of the display Framed texts indicate active commands texts without frames are for information only The MAIN and RETURN buttons are used to navigate back from the current menu In chapter 3 2 the menus their functions and their handling are described in detail 10 Menu Structure SAVE SCANNER i CALL 4 OFFSET OFFSET SAVE M1 300 SAVE M2 CORR CALL M1 ACF 4 MENU A SENS SAVE SENS CALL CALL M2 1 SCANNER OFFSET SENSI OFFSET 4 RESOL TIVITY 655 MAIN MENU ACQUI AQUIRE ARES 256 CORR SITION MENU MENU FREE RUN SPEC MENU gt gt gt TRIGG MENU 4 DISPLAY k RESOL RUNNING m _ STOP ACF SPEC gt gt gt ACF ACF FILTER ER P AVERAGE oe me SMOOTH ON gt gt OFF OFF gt gt ON AVER 1 BARGRAPH BARGRAPH MENU MENU FWHM v 24 RS 232 gt OFF lt gt ON sPEC BAUDRATE BAUDRATE gt MENU FWHM A OFF lt gt
11. ON in BRIGHT 38400 hes sd i CALL tX AA SPECTRUM dla ITIME AL BRIGHT ITIME RESOL gt SPEC 2ms RESOL DISPLAY MENU SRES x1 Fig 4 Menu Structure Menu Structure 11 3 2 3 2 1 Control Menus After switching on and passing the initial routine the autocorrelator starts with the last set of measuring parameters and the main menu fig 4 with the actual detector signal being displayed Main Menu With the corresponding keys the correlator menu can be activated the measurement can be stopped and different filter values for the AC signal channel can be selected At the lower right corner of the display the actual parameters are shown Scan range Data acquisition mode Correlator sensitivity Average number Delay resolution Crystal tuning angle If activated the measured data ACF half width FWHM is displayed on top of the display 12 Menu Structure 3 2 2 MAIN MENU CORR MENU SPEC MENU RUNNING gt gt gt STOP FILTER ON gt gt OFF Fig 5 Main Menu Correlator Submenus 3 2 2 1 Correlator Basic Menu By pressing the corresponding key one out of 5 submenus can be selected SAVE CALL Saving the current ACF or displaying saved ACF while stopping the measurement SCANNER OFFSET Control of interferometer Zero position peak centering SENSITIVITY Control of signal sensitivity ACQUISITION Control of data acquis
12. PulseSc out Autoconelator PScout Series User s Manual GO NNevvport Experience Solutions Preface Warranty Newport Corporation warrants that this product will be free from defects in material and workmanship and will comply with Newport s published specifications at the time of sale for a period of one year from date of shipment If found to be defective during the warranty period the product will either be repaired or replaced at Newport s option To exercise this warranty write or call your local Newport office or representative or contact Newport headquarters in Irvine California You will be given prompt assistance and return instructions Send the product freight prepaid to the indicated service facility Repairs will be made and the instrument returned freight prepaid Repaired products are warranted for the remainder of the original warranty period or 90 days whichever is longer Limitation of Warranty The above warranties do not apply to products which have been repaired or modified without Newport s written approval or products subjected to unusual physical thermal or electrical stress improper installation misuse abuse accident or negligence in use storage transportation or handling This warranty also does not apply to fuses batteries or damage from battery leakage This warranty is in lieu of all other warranties expressed or implied including any implied warranty of merchantability or
13. allow time for the instrument to warm slowly to the temperature of the laboratory Detector and Crystal Installation An optics set consists of a crystal and a detector For shipment the crystal is removed and needs to be installed in the optics unit The detector unit will be installed when you receive the Pulse Scout A detector unit has already been pre installed If there are several detectors the detector for the laser wavelength should be installed Crystal exchange lid Detector unit Fig 16 Crystal and Detector Access 21 22 Installation 4 1 1 Crystal Exchange Before exchanging the crystal make sure that there is no laser light passing through the optics unit 1 In order to have the handhold of the crystal holder easily accessible tune crystal angle to about 500 2 Switch off control electronics so that the scanner is motionless and the detector is inactive 3 Open crystal exchange lid Fig 17 shows the optics unit with the crystal exchange lid removed and crystal installed The crystal is fixed to the crystal retainer by a magnet Fig 17 Open crystal container with Fig 17 Close up of crystal installed crystal 4 Remove the crystal by slightly tilting the handhold of the crystal holder see arrow in Fig 17 and pulling it out Fig 17 Crystal Compartment with Crystal Installed Crystal pin Crystal Handhold Magnet Fig 18 Crystal Assembly Installation 23 4 1 2 Slot f
14. bly in the horizontal plane will move the back reflection in the horizontal plane and tilting the optical assembly up or down with the third leg will move the back reflection up or down Once the optical assembly is grossly aligned it should be clamped to the table Final adjustments can be made by adjustment of the mirror mount that holds the sampling element For measurement of the AC signal tilt back the variable aperture Collinear Autcorrelation Although it is often preferred to operate the autocorrelator in the background free or non collinear mode it is sometimes easier to find an autocorrelation signal in the collinear mode If one has trouble finding the autocorrelation trace then turn the screw see fig 1 all the way in for collinear operation In collinear mode you are guaranteed to see a signal from the autocorrelator if the crystal is aligned at the proper angle even if the two replica beams do not overlap temporally or spatially Hence due to the fewer variables involved it is best to use this collinear configuration to begin with the optimization of the autocorrelation trace Finding the Autocorrelation Trace Switch the autocorrelator ON After an initialization period the unit is ready for measurement At first you will see a flat horizontal line over the whole screen Slowly increase the GAIN until either a clear signal or noise is observed If the autocorrelator is responding to room lights dim the
15. d by temporal overlap is detected Hence the contrast between exactly overlapped pulses and pulses with no overlap is infinite Normally the nonlinear crystal is inaccessible because it is slightly hygroscopic and can become fogged by high humidity However should the crystal need to be cleaned or exchanged it can be accessed by removal of the upper cover of the optical assembly General Information 1 2 4 Signal Detection Second harmonic light generated in the mixing crystal is detected by a photomultiplier tube or photodiode which has been filtered to block transmission of light at the wavelength of the laser The photo detector converts light intensity into an electronic signal This signal is then electronically amplified and filtered and is available at the Y BNC connector at the rear panel of the electronic controller 2 1 Specifications and Models Specifications Optical parameters Max scan range 15 ps Resolution lt 1 fs Scan frequency approx 20 Hz Linearity distortions lt 1 Input polarization E horizontal E vertical with polarization rotator Standard Wavelength Range 700 1100 nm Optional Wavelength Ranges 420 550 520 750 or 1000 1600 nm PMT Detector Sensitivity lt 107 W Pav X PprAK Photodiode Detector Sensitivity IW Pav X PpgAK Input beam height adjustment 75 115 mm Electrical parameters Input Power 95 264 V AC 50 60 Hz Analog Outputs 0 10 VDC Serial In
16. erometer arm containing a retroreflector One of the retroreflectors is mounted on a special linear translation stage that can change the length of one interferometer arm in a continuous fashion The two replica pulses then are recombined by the beam splitter focused by a mirror and overlapped in a nonlinear optical crystal Light generated in the nonlinear crystal is then detected by a filtered photomultiplier PMT tube or photodiode A portion of the back reflected beams can be seen on the window next to the input aperture and are used for alignment of the beam into the autocorrelator Time Delay The time delay for generation of the autocorrelation trace is introduced by movement of a retroreflector mounted on a linear delay stage Whenever the instrument is turned on the delay stage will be oscillating at its resonant frequency of approximately 10 Hz A voltage proportional to the scaled position of the delay stage is available at the X BNC connector at the rear panel of the electronic controller Mixing Crystal When tilted to the proper angle a small amount of frequency doubled light is generated in the nonlinear crystal In collinear geometry the two replica pulses follow the same beam path and generate second harmonic light whether or not they overlap temporally The intensity contrast between exactly overlapped pulses and pulses with no overlap is 3 1 In non collinear geometry only the second harmonic light produce
17. ition DISPLAY MENU Control of data display Menu Structure 13 CORR MENU SAVE CALL SCANNER OFFSET SENSI TIVITY ACQUI SITION DISPLAY MENU Fig 6 Correlator Basic Menu 3 2 2 2 Correlator Save Call Menu The controller features two memory places for ACF traces With the Save Call function the ACF Memory can be controlled SAVE M1 SAVE M2 saves the current ACF to memory MI M2 CALL MI CALL M2displays the saved ACF of MI M2 while measurement is stopped SAVE CALL SAVE M1 SAVE M2 CALL M1 CALL M2 Fig 7 Correlator Save Call Menu Menu Structure 3 2 2 3 Correlator Sensitivity With the SENSITIVITY function the signal amplification can be varied in addition to the GAJN function By pressing the or key the sensitivity is increased or decreased respectively by a factor of 3 in the range of 1 to 30 The OFFSET parameter controls an offset voltage to compensate dark current and other background signal components It is stored separately for each sensitivity level Please note that the offset parameter is changed only after releasing the button Block the beam to set this parameter and make sure that the signal level is not below zero check with scope at the analog y output or set slightly above lower edge of display ACF SENS SENS OFFSET 655 Fig 8 Correlator Sensitivity 3 2 2 4 Data Acquisition Menu With the ACQUIRE MENU
18. lectronics is located the main input power connector the connector for the optics module DB25 an RS232 serial interface DB9 optional spectrometer DB15 and the BNC connectors Trigger Input Delay and AC Intensity General Information l l Exchangeable detector module 1 In fig 3 the principal optical layout and the main electrical units are shown schematically IM Input Mirror IA Input Aperture CW Control Window BS Beam Splitter FM Focus Mirror C Ultrathin SHG Crystal 100 40 um A Aperture Fi Filter Det Detector module Xx Y Tigger Power LCD display LCD Micro display controller Return blanking e Signal Angular Delay driver processing driver 3 measuring unit hd S Delaydrive B Delay Retroreflector sensor 8 c Angular z a drive oS 1 E pET N d BS Retroreflector 4 Ly l Fi c l FM Deu een Ww IA A Fig 3 Optical Layout Scheme General Information 5 1 2 1 2 1 1 2 2 1 2 3 Optical Assembly Overview The optical beam path can be traced in fig 3 Entering the optical assembly at the input aperture the laser pulse is divided into two parts at the beam splitter Each part traverses an interf
19. one can control Measuring modes untriggered for high repetition rates triggered for repetition rates lt 10 kHz envelope function for fringe resolved ACF Delay resolution for a reduction of measuring time at low repetition rates in Trigger and Fringes mode only Signal averaging for noise suppression Signal display smoothing for smoothing structured functions The measuring mode is selected with the FREE RUN gt gt gt TRIGG key In the untriggered mode FREE RUN the ACF data are measured continuously with the maximum acquisition rate and displayed and refreshed immediately Menu Structure 15 In the triggered mode TRIGGER the delay and signal values are measured digitized and saved only synchronously to an electrical trigger pulse from the measured laser applied at the trigger input These pairs of measured data are superposed until a complete ACF is displayed Caution there is no ACF measurement without trigger pulse The FRINGES mode is a special function to display fringe resolved ACFs While acquiring with maximum rate this mode detects the maximum and minimum AC signal value of each delay channel to display the envelope of a sinusoidal modulated collinear ACF For tuning the phase matching in this mode it is necessary to switch to zero scan AQUIRE MENU FREE RUN gt gt gt TRIGG RESOL AVERAGE SMOOTH OFF gt gt ON Fig 9 Data Acquisition 3 2 2 5 ACF Resolution With the ACF RESOL f
20. ooting 6 1 Rotation of Plane of Polarization Usage of a Polarization Rotator 2 2 plate The effect of polarization rotation can be very wavelength sensitive depending on its type Rotation by a Double 90 Beam Steering Two mirrors mounted 45 to the input beam and steering it in different planes cause an effective wavelength insensitive 90 rotation of the plane of polarization Such a polarization rotator is included M1 Polarization Il plane of incidence h M2 Polarization L plane of incidence 33 34 Troubleshooting 6 2 6 3 6 3 1 Fig 17 Polarization rotator Fundamental Overload At very extreme wavelengths and input power levels the ACF can be superposed by a larger background from the fundamental wave in the collinear case This can be avoided by using the non collinear interaction or the use of special filters and detectors Common Errors No SHG Signal Potential Causes 1 Wrong polarization direction 2 Wrong alignment 3 No or too long input pulse Check 1a Check with polarization rotator see 7 2 1b Introduce a polarization rotator in the input beam 2 Check beam position at input aperture 3 Check back reflection at control window 4 Check FOCUS position 5 Check phase matching 6 Check with an independent method fast photodiode spectral width etc Troubleshooting 35 6 3 2 6 3 3 Input Power Too Small Potential Causes 1 Delay zero
21. or crystal pin Fig 19 Crystal Compartment with Crystal Removed Detector Exchange Before exchanging the detector unit make sure that there is no laser light passing through the optics unit 1 Switch off control electronics and disconnect the cable to the optics unit 2 Unfasten the two fixing screws pull out detector unit and replace with the detector required for your actual laser wavelength to be measured 3 Fasten fixing screws 4 Connect controller to optics unit and switch on The installed type of detector PMT or PD is recognized automatically Fixing screws LI gt PMT DETECTOR G Fig 20 Detector Module Exchange 24 Installation 4 2 4 3 4 3 1 Interconnect Cables Interconnect the optical unit and control electronics with the 25 pin cable provided Connect the electronics to the main power source using the AC adapter If using the optional spectrometer connect with the 15 pin cable provided with the spectrometer Input Alignment Baseplate Attachment By adjusting the columns the beam height can be varuied They can be positioned either above or below the base plate of the autocorrelator Caution The columns and the screws function as a unit Never unscrew the columns completely as they are connected by a spring which will come loose if the columns are not tightenend to the screw In order to change the position of the columns the whole leg columns and screw has
22. position outside of scan range 2 Compare with sensitivity see Specifications Check 1 Check at wider scan ranges check the DELAY position see Specifications offset setting No Clear ACF Potential Causes Wrong scan range No or too long input pulses Check Check at wider scan ranges Check with an independent method fast photodiode spectral witdth Safety For the application of lasers you have to pay attention to safety rules according to the used laser class Incorrect handling and operation of lasers can be hazardous to your health Prevent the Autocorrelator from humidity because the SHG crystals are slightly hygroscopic and they are not mounted in housing because of dispersion 37 8 Factory Service Information 8 1 Service Form GYD Newport Corporation U S A Office 800 222 6440 FAX 949 253 1479 NNevvport Name Return Authorization Please obtain RA prior to return of item Company Address Date Country Phone Number P O Number FAX Number Item s Being Returned Model Serial Description Reason for return of goods please list any specific problems 39 40 Factory Service Information Notes Newport Corporation Worldwide Headquarters 1791 Deere Avenue Irvine CA 92606 In U S
23. se the beam distance slightly to measure a collinear ACF without interferences Calculation of the ACF Half Width For the calculation of the ACF half width the background value is taken at the edge of the display The difference of this value and the maximum is taken and halved After that the crossings of this amplitude value and the ACF right and left from the maximum are locked for Their distance is the measured half width which is displayed at the top of the display That s why the ACF peak has to be zero at the edge of the display for measuring a correct value with this algorithm if necessary change the scan range After getting the ACF displayed one can measure the half width of the autocorrelation function It is defined as FWHM Full Width at Half Maximum which means the width at the half intensity level between the maximum of AC peak and the baseline outside the peak fig Most comfortable is the application of cursors otherwise the oscilloscope grating can be used Measure ACF width b and complete scan width B maximum scan Due to the automatic scan control the complete width B is defined by the actually selected scan range Therefore the autocorrelation half width FWHM is calculated as FWHM b B x Scanbereich Operation 31 To get the real pulse duration one has to correct the AC width with a form factor depending on pulse shape t FWHM x Fig 16 Calculation of ACF Half Width 6 Troublesh
24. t ON T XAN OFF lt gt ON Fig 13 Bargraph Menu 3 2 3 3 Cursor Basic Menu The CURSOR MENU which is activated at any time by a separate CURSOR key below the display controls the different cursors These cursors allow manual measurements at the ACF alternatively to the automatic FWHM readout CURSOR MENU ACF CURSOR gt gt OFF EXIT Fig 14 Cursor Basic Menu Menu Structure 19 3 2 3 4 Cursor Control Menu After the activation of the cursors ACF At 3 horizontal and 2 vertical green lines are displayed with one of them marked by higher intensity This one is the cursor which can be moved with the CURSOR lt gt keys below the display By pressing the corresponding keys HOR 1 2 and VERT 1 2 the active cursor can be changed The third horizontal line in the middle shows the half amplitude between the lower and the upper horizontal cursors When they are set to the peak and the background level of the ACF the crossings of the half amplitude cursor with the corresponding function give its actual half width which can then be measured with the vertical cursors At the top of the display the actual positions of the vertical cursors are displayed CURSOR ACF HOR 1 HOR 2 VERT 1 VERT 2 EXIT Fig 15 Control of Cursors in ACF 4 4 1 Installation If the system has been shipped during the cold winter months please
25. terface RS232 Trigger input 5 470 9 Dimensions L x W x Optical Unit 104 x 141 x 111 mm Control Electronics 292 x 280 x 186 mm Alignment Base max 62 x 148 x 132 mm x Tau Pav X f rep Tau Pulse duration f rep Repetition rate Specifications and Models 2 2 Standard PScout Series Products Below is Newport s standard PScout Series offering Other custom configurations are available by contacting Newport Autocorrelators PSCOUT HR PulseScout Autocorrelator 50 3500fs 700 1100nm PMT PSCOUT LR PulseScout Autocorrelator 50 3500fs 700 1100nm Photodiode PSCOUTSP HR PulseScout Autocorrelator 20 3500fs 700 1100nm PMT PSCOUTSP LR PulseScout Autocorrelator 20 3500fs 700 1100nm Photodiode PulseScout Upgrades and Accessories PSCOUTUPG BLUEI Blue PMT Detector Module 420 550nm PSCOUTUPG BLUE2 Blue PD Detector Module 420 550nm PSCOUTUPG REDI Red PMT Detector Module 520 750nm PSCOUTUPG RED2 Red PD Detector Module 520 750nm PSCOUTUPG HR NIR PMT Detector Module 700 1100nm PSCOUTUPG LR NIR PD Detector Module 700 1100nm PSCOUTUPG IR1 IR PMT Detector Module 1000 1600nm PSCOUTUPG IR2 IR PD Detector Module 1000 1600nm PSCOUTUPG SP PSCOUT Short Pulse Conversion Kit 20fs PSPECNIR CCD Spectrometer 700 1100nm PSPECVIS CCD Spectrometer 300 700nm PSCOUT IEEE PulseScout IEEE Inferface PSCOUT USB PulseScout USB Interface PSCOUT WINDOWS PulseScout Windows Control Software RS232 PSCOUT LABV
26. thout an RMA E mail rma service newport com When calling Newport Corporation please provide the customer care representative with the following information Your Contact Information Serial number or original order number Description of problem 1 hardware or software To help our Technical Support Representatives diagnose your problem please note the following conditions Isthe system used for manufacturing or research and development What was the state of the system right before the problem e Have you seen this problem before If so how often e Can the system continue to operate with this problem Or is the system non operational Can you identify anything that was different before this problem occurred Preface Table of Contents Warranty idea e ee duode gan Mes dad donk vats tp Ate cl til n fa ii EU Declaration of Conformuity cesses eee eee enne ns iii Technical Support Contacts e ber c rad es iv Table OT Contents i aaa 1 General Information 1 Ll Introd GtiODuonst eerie quedo ded une un 1 L2 x9ppicalAssembleu o NN 5 NEN EE ranis een aueh 5 1 22 ve Delay Ce Em RE ense es 5 1 2 3 ry Stalls o ae 5 1 24 Signal Detection a 6 2 Specifications and Models 7 ZA Speeifestions oue adeo edt rasen 2 2 2 Standard PScout Series 8 3 Menu Structure 9
27. unction the delay resolution can be reduced for a faster but more inaccurate measurement in the trigger mode By pressing the or keys the resolution can be increased or reduced by a factor of 2 in the range of 256 to 32 16 Menu Structure ACF RESOL ARES 256 Fig 10 ACF Resolution 3 2 2 6 ACF Averaging With the AVER function the ACF can be averaged over n cycles The displayed number n is the inverse weight the actual measured signal value influences the displayed ACF with The response time of the displayed ACF to variations is decreasing correspondingly The average number is increased or decreased by a factor of 2 by pressing or key ACF AVERAGE AVER 1 Fig 11 ACF Averaging Menu Structure 17 3 2 3 Other Submenus 3 2 3 1 Display Menu The DISPLAY MENU is used for controlling the displayed functions and parameters With this the parameter calculation can be switched on or off and a bargraph menu can be selected This menu lets you control the data transfer rate of the serial interface and control the display brightness as well DISPLAY MENU ACF SPEC gt gt gt ACF MATH ON gt gt OFF BARGRAPH MENU RS 232 BAUDRATE BRIGHT Fig 12 Display Menu 3 2 3 2 Bargraph Menu In the BARGRAPH MENU an analog bargraph displaying the actual ACF half width is switched on and off 18 Menu Structure BARGRAPH MENU FWHM OFF lt gt ON FWHM AX OFF lt g
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