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BeamScope™-P5

1. 1 Determine the plotted value R 04 1 10 mW for your wavelength e g 70 mw at 633 nm Wavelength in um 2 Fora different slit or beam multiply Ps by 0 05 beam diam um slit width um 3 Fora pinhole multiply Ps by 0 05 x beam diam um pinhole diam um 4 The total incident power must never exceed 2 0 W The minimum detectable signal at useful SNR is lower by 55 dB optical for the Silicon detector 50 dB for Ge 25 dB for InAs For Pulsed Beams use the peak power in the pulse as your starting point in the calculations The actual saturation power may be higher than this but this is pulsewidth amp PRR dependent For higher power densities insert neutral density film up to ND 2 0 behind the slit A typical 3 5 floppy diskette is ND 2 0 at 630 nm BeamScope P5 1 7 2 w lt lt Si a ay o g To a Introduction 1 4 20 La nag BeamScope Phase 5 DataRay Inc CAUTION Avoid reflections trom metal surfaces Do not remove data link cable with power on 14 20 Me 1 3 20 az 4 5 6 0 In most laser assemblies elliptical beams have a major axis at 0 45 or 90 to the horizontal and the Rectangular Head BeamScope may be mounted at any of these angles Discontinued January 2001 Rectangular Head Rotatable Head 1 8 BeamScope P5 Introduction For the EPH vers
2. cn aaa 10 4 3 Second Moment Beam Diameter 5 ACKNOWLEDGEMENTS 6 REFERENGES L lO ai APPENDIX C TECHNICAL SUPPORT SALES RETURNS DISTRIBUTORS AND REPRESENTATIVES csssssscsssssssssssssssssssssssesscsssessenssssssssssssssnsesscsssesssssessssssssssnseses 13 APPENDIX D BEAMSCOPE DATA STRUCTURES oorrrrrcrrreresererereezeneesesenenzonen 14 XDD BeamScope P5 A 1 Appendices Appendix A BeamScope P5 Function Request Form To DataRay Inc Fax 303 494 1431 Please answer the questions on this form to request suggest a software and or hardware upgrade Fax the completed form to DataRay We will normally give an initial response within five working days Your Name Organization Phone Fax Email 1 What is the request suggestion What exactly would this do 2 What equations and or parameters does this function use 3 How do you want the results displayed and or printed 4 Please briefly describe the beam that you are trying to measure Wavelength CW Pulsed ____ Mean Power Beam Dimensions ___ _ mm Other A 2 BeamScope P5 Appendices APPENDIX B M Squared and Its Measurement 1 Why Care about MSquared There are several possible reasons for understanding M squared M and wanting to measure its value for a laser system O ItistheQA delivery or acceptance criterion on a laser or laser system Q You are attempting to understand why
3. 4 5 KNIFE EDGE MODE 4 6 GAUSSIAN FIT ALGORITHM 4 6 1 Gaussian Fit Algorithm USING THE MAC CESSORY aride Sl NEW M ACCESSORY USER Lie 5 2 5 2 M2 HARDWARE SETUP 33 OPERATION ocena onnaa ethos 5 4 SAVING amp PRINTING THE RESULTS 5 95 INTERPRETING THE RESULTS e i scion dees rain 2D SCANNING STAGE ssssssssesscsosssssesececoceoossossssseescccoessossssseseceeoesoossssseeseseoesoosssssesesseeee 6 1 GA INITIAL SETUP geraas a E E N E 6 1 G2 OPERATION rira i n E E NEER E E 6 2 6 3 FREQUENTLY ASKED QUESTIONS cei 6 3 APPENDICES Appendix A BeamScope P5 function Request Form Appendix B M Squared and its Measurement Appendix C Technical Support Returns Distributors amp Representatives Appendix D BeamScope P5 Data Structures INDEX CHAPTER ONE 1 INTRODUCTION 1 1 WELCOME csc ol Ain Aa Rain 1 2 FUNCTIONAL DESCRIPTION iss sscseiesesescdesizsecesaysciarscesessdsacsstuesesuespesnevescaassasseoeevesssesens 1 3 MANUAL CONVENTIONS ccccssssesscsesseseessseesescesescescesessesescencsesseeceaenseesesenseecaseneeesas 1 4 MANUAL AND COPYRIGHT NOTICE cscssesessesceseeseseesescescecesceecneeeceeeneeeens 1 5 PRODUCT SPECIFICATIONS LS Computer Requirements iii 1 12 1 1 WELCOME Welcome to the BeamScope P5 This P5 version of the BeamScope product family was first introduced in December 1998 continuously improved since then and defines state of the art large b
4. BeamScope P5 4 27 BeamScope Functions This compensation has been modeled as the movement of a slit across two dimensional Gaussian beams and top hat distributions The graphs show the compensation error as a function of beam diameter slit width for a simple compensation algorithm square root of the difference of the squares clip level independent and for the more complex clip level dependent algorithm employed by DataRay Error versus Slitwidth Beamwidth Ratio Circular Top Hat Beams 15 10 Difference of Squares Corrrection 13 5 5 Formula 13 5 Clip 0 5 di 5 DI Formula Difference of Squares 50 Clip Corrrection 50 Clip 10 15 20 25 0 0 1 0 2 0 3 0 4 0 5 4 5 KNIFE EDGE MODE When the beam is smaller than the slit you may use knife edge mode to measure the FWHM Full Width Half Maximum beam diameter i e at the 50 Clip Level The slit should be at least a factor of two wider than the 1 e width of the beam being measured Note that the displayed profile will be the normalized raw detector output uncompensated for slit width For example a 10 um diameter beam scanned with a 25 um slit will display a flat topped signal profile with width of 25 um at the 50 level In this mode the software employs a knife edge scan algorithm to analyze the data The displayed raw scan signal is differentiated for one of the edges to give the beam profile No correction for
5. Click on Flip Slits to flip the slits as illustrated to a mirror image If the slit orientation is set wrong the Y Incsement Slit K K centroid will display in the wrong sie ceo sence Match Axis to Apertures BeamScope P5 BeamScope Functions i ed ia to open the Aperture Select dialog box shown left The checked boxes should be as shown Snot dan San SA For current releases of the software Y gt Apl Ap2 gt Ap3 Ap4 ignore Z Ap3 Ap4 amp Set to defaults which are hangovers from earlier versions Focus Xand Z gt Yand Z Z gt Apl Ap2 gt Ap3 gt Ap4 Z is sometimes used for focus ASSIGN SLITS CTRL X also For info call 408 338 9055 takes you to this box Mese BeamScope P5 4 25 BeamScope Functions Program Head EEPROM CTRL E As previously mentioned there are almost no circumstances in which you will need to program the head except Maximum Speed 6 typ Greater than 6 is slower Software version 5 3A changed this default to 15 If the head is inadequately mounted head vibration may affect the measurement of profiles particularly small ones The affected profiles appear to have multiple shoulders on the profile As a last resort set this value much higher e g to 100 to drastically slow the head and click OK If the structure remains it is almost certainly real EEPROM_DATA 4 26 BeamScope P5 Error BeamScope Functions 4 4 SLIT MOD
6. Page Header above or the Help Notes and Task Bar below Opens the Help system This manual is frequently the better reference IK BeamScope P5 4 7 BeamScope Functions 4 2 MAIN SCREEN SECTIONS If you read nothing else read section 4 2 14 on the Search function Before introducing sections of the main screen top to bottom and left to right in section 4 2 4 sections 4 2 1 to 4 2 3 address issues common to all sections of the screen 4 2 1 Pass Fail for QA and Production Testing BeamScope makes it simple to test measured parameters against a preset level and to display this fact in real time Pass Fail can be set for all displayed parameters making BeamScope an ideal tool for use by less technical staff in QA and Production Test Enter Alt S P to access the Pass Fail Parameter Setup dialog box Beam Width Parameters BeamScope P5 c 1996 DataRay Inc Apl 13 5 Ellipticity vi Apl 13 5 Centroid X offset absolute vi Ap2 13 5 Centroid Y offset absolute 1000 00 v Ap2 13 5 aa Password __ Lock Update Interval Seconds Gaussian Fit Parameters TopHat Parameters Minimum Maximum test Minimum Maximum test fot Gauss Fa V ADI Tonia 4 102 Gaus Fi K Ap Tonia 4 Mean Fi opta Meo 4 Aves Show as percentages Display Form 1234 um gt Show as factors gt 1 23 mm gt 1 234 mm In most cases you will want to work at 4 Show as percentages Display Form 1234 um Select the parameter
7. but if it is still there at the end of the M scan then recheck the set up in the manner suggested in the box Click on SAVE M2 to save the scan It is VERY important that the waist occurs somewhere in the center of the scan say within 4 mm If not change the lens to BeamScope distance to adjust the waist position and redo the M scan This is normally most easily accomplished by unbolting the lens and bolting it back into a different position on the moving carriage Once a successful scan has been accomplished the factors K M and waist location are displayed as described in Section 5 1 The waist location is the distance from the principal plane of the lens You can change the clip level or width method mode and re calculate the M data by left clicking on the lower central box below the Beam Widths title as described in 4 3 3 5 4 SAVING amp PRINTING THE RESULTS 1 2 3 4 5 Save the results by pressing the SAVE M2 button and completing the dialog box You can recall the results by pressing the RECALL M2 button You can also recall the M data into the BeamScope s 100 profile data buffer by pressing the Recall File button and selecting the m2 file You can then look up each profile individually a You can print the M full screen with or without notes by using the ala E print hot buttons or from the File pull down menu You can copy the screen to the clipboard by simply pressing Ctrl T 5 5
8. target area and vector 3 1 5 Change the Beam Diameter Definition Beam Widths Buttons This is a set of seven button areas controlling the display of the beam diameters and their corresponding clip levels Beam Widths 0 164 mm 13 5 Clip 0 167 mm 0 164 mm 13 5 Clip 0 167 mm The two center Clip Level buttons open the Clip Level Entry dialog box allowing the user to set a desired clip level or select the use of the Variance Second moment beam diameter definition With a beam profile that is pure Gaussian the Variance definition is exactly the same as selecting 13 5 but if your beam is non Gaussian the Variance method is more consistent BeamScope P5 3 5 3 1 Quick Start Tutorial Note that two distinct clip levels and or Clip Level Entry x methods can be set concurrently in the upper x Level 2 and lower Level 1 levels Knife Width Calculation Method edge is only valid for a 50 Clip Level Clip Level gt Variance second moment If used clip level is ignored gt Knife Edge FWHM gt 13 5 17e2 50 FWHM gt 86 5 Clip 50 00 x Place the cursor on one of the four beam diameter buttons results and click the right mouse button You can now aistomize the color of the button and the colors of text in different states 3 1 6 Pass Fail Indication for QA amp Production Testing BeamScope makes it simple to test measured parameters as above or below a preset level and
9. 1 BeamScope mounting 2 13 FieldPack 2 8 PC Card 2 3 Software 2 4 ISO 11146 Standard 4 27 A 6 J Job File 2 12 4 3 Icon 2 4 K Knife Edge mode 4 28 Algorithm 4 28 L Laser CW 4 23 Divergence angle 4 19 Pulsed 4 23 Log 4 5 4 21 Log Data to Hard Drive 4 21 Log Data 3 13 4 5 4 21 Logarithmic profiles 3 7 4 16 BeamScope P5 Appendices M M M Squared 5 1 Hardware 5 4 Interpreting the Results 5 8 Meaning of A 3 Plate Baseplate 1 10 Mounting 1 11 5 5 Saving and Printing the results 5 7 Software 5 1 Specifications 1 10 Main Screen 4 2 Modulated sources 4 23 N Noise floor 4 16 O Options 4 4 Options Menu 4 4 4 18 Orientation see Ellipticity P Palette 4 6 Pass Fail 3 6 4 8 Part Numbers 2 1 PC Card Installation 2 3 Plot History 4 16 Power 3 7 4 11 Calibrate 4 12 Contained 4 12 Included 3 7 Print Current screen with date 4 3 Print with notes 3 8 4 3 Setup 4 3 Profile 2D 3D 3 7 4 13 Access Page Up Page Down keys 3 14 xaz Appendices Analyze 3 13 4 21 Beam Profiles Area 4 15 Capture 3 13 4 5 Data Buffer 3 3 Feature Included Power amp Distance 3 7 4 16 Linear 3 7 4 16 Log 3 13 4 16 Logarithmic profiles 3 7 4 16 Recall and Process 3 14 Rotating 3 7 4 14 Tilt 3 7 4 13 Program EEPROM 4 26 Pulsed lasers 4 23 Q QA see Pass Fail Quick Start Tutorials Software only 3 2 Hardware 3 10 R Ran
10. 500 Hz Using a pulsed laser at a high Ki A repetition rate leads to a comb of samples Click and drag the slider to set Freq X XXX KHz closely equal to the laser pulse repetition rate and hence a sample interval equal to 1 Freq BeamScope P5 4 23 4 3 BeamScope Functions If the peak height of the pulses is constant and the peaks represents the profile envelope then check Point to Point to connect the dots If the average energy of the pulses over the sample period is constant check Mode Alternate to average the signal over the sample period Modulated sources Move the slider to the left to set a rejection filter centered at the frequency shown E g For the rejection of line frequency harmonics in the source or background e g twice line frequency from an incandescent lamp Important With pulsed lasers in order to avoid EMI ElectroMagnetic Interference it is frequently necessary to use the BSCABS 3 0 or 4 5 shielded cable See page 2 2 Slit Orientation CTRL O This box sets the slit orientation As shown is the normal orientation Q 4 24 Optional Gain Parameters This is normally set as shown See Section 4 2 7 for a more detailed description M squared Input Parameters Only relevant when using the M Accessory See Chapter 5 Divergence Angle Z distance ee Sie reson See Section 4 3 1 Click on Increment Slit to increment the slit orientation in 45 steps
11. Analysis window Click on File Load to Open a logged data file Examine the logged profiles and statistical data including the mean and its standard error Below is an example of the whole screen display Note the Save Load Edit and Print options allowing export to reports BeamScope Data Analysis C BSCOPES HENELOG LOG Samples 8 Ellapred time 0 H 0 M 7 5 Ele Load SeveFlesrTem Loed Tew Fie Edt Test Fie Eini ErntwithNoter Width um Gt 3 6 Max 599 9 Min 509 4 Mean 592 7 Std Enor n hean 0 49 P Width um E 3 5 Max 593 9 Mih 589 4 Mean 592 7 Sto Emor h Waan 0 48 a e ftt1 a Width ium Ei 3 9 Max 596 2 Min 954 6 Mean 555 5 Std Emor m Maan 0 23 BeamScope P5 4 21 BeamScope Functions 4 3 3 Setup Scan Head Setup F6 The Head Setup and Options dialog box is shown below Going down the left hand side column Number of Slits IMPORTANT Optional Gain Parameters TE z z Le ee Einki Mininum Gain gt 0 0dB Dual Slits TE E De Corrects for dual slit mount angle errors Search Ham firat y Normalize Profiles default is on X Slit Factor M Squared Input Parameters Y Slit Factor Wavelegnth 0 6328 um vi Auto Range _ Vane bese Y Tracking required for Centroid Centroid Clip Level 13 5 Focal length mm v Auto TEM x x Lens to slits Yi Auto Search Auto Gaus Peak nearest distance Dai Filter F
12. DOS program x in top right corner answer Yes to the Windows Warning box click OK in the BeamScope board not detected box BeamScope will open If all you want to do is to analyze some previously saved data then just carry on To use BeamScope in live mode you must first close BeamScope and correctly attach the cable and or power supply BeamScope may be then be reopened and should function normally BeamScope P5 2 11 Installation Job files It is possible either now or at any later stage to link a job file Saves the BeamScope settings see Section 4 6 to the current BeamScope icon To do this right click the BeamScope icon select the Properties item then select the Shortcut folder Q Inthe Target section it should look similar to the following C BSCOPE BSCOPES EXE Q Add atthe end JobName job It should then look similar to C BSCOPEBSCOPES EXE JobName job Where a Jobname such as Defaults is the name to be assigned to the Default settings O If the attached job file does not already exist the BeamScope P5 software will automatically create one A warning that it didn t exist will be dis played WARNING Never hot connect or disconnect the head while the software is powered up This can cause damage to the head and or the PC card electronics You may also create additional icons linked to other job files To create an additional icon in Windows Explorer find Phase5 exe and click and drag it onto t
13. Dialog CTRL V Opens the Beam Widths Averaging dialog box See Section 4 3 1 Average Widths No averaging The user can select a simple rolling average of 1 5 10 20 or 50 samples After the maximum sample number is reached the oldest readings are dropped from the average as new readings are added See above and Sec 4 3 1 for more complex averaging 4 4 BeamScope P5 BeamScope Functions Log Log data to hard drive Log data to hard drive Opens a dialog box that allows the user alyze es to create a log file which is updated at the user defined update interval set in Pass Fail Setup while the system is operating Analyze Profiles Opens an existing log file and generates measurement statistics Palette Help Setup Pass Fail Setup Pass Fail Setup Scan Head Setup F6 Opens a dialog box that Slit Orientation CTRL 0 allows the user to specify Assign Slits CTRL X PASS FAIL values for Program Head EEPROM CTRL E measured parameters i Pass Fail will be indicated E GI automatically by changing the on screen color of the parameters Scan Head Setup F6 F6 opens the Head Setup and Options dialog box that allows the user to set important head parameters such as the number and size of the slits pinholes gain limits and other options See Sec 4 3 2 Slit Orientation CTRL 0 Opens the Slit Orientation dialog box which allows the user to adjust for the mounting orientation of the he
14. FieldPack z or BeamScope Ipt ems your decision C Connect the Cables amp Start the Software 5 Connect the cables as follows e 12 VDC Power supply between a 100 240 VAC 50 60 Hz wall socket and the 12 Volts DC only input on FieldPack e 25 pin D connector cable from the parallel port on the computer to Parallel Port on the FieldPack e 15 pin D connector cable from the connector on the BeamScope head to the 15 pin D connector on the FieldPack e If you also have an M2B Scan Stage connect the 8 pin flat network connector from the Scan Stage to the connector on the FieldPack This can be a tight fit 6 Double click the BeamScope FieldPack icon to start the software A DOS screen may flash before you eyes Wait up to ten seconds The BeamScope head will make clicking noises as it references to an internal physical stop and the BeamScope main screen should appear If this does not happen see Q1 below If it does got to Section 2 5 Congratulations You have successfully completed FieldPack Installation WARNING Never hot connect or disconnect the head while the software is powered up This can cause damage to the head and or the PC card electronics Notice x Frequently Asked Questions 3 Q1 I started the BeamScope software and this 2 Notice appeared BeamScope board not detected BeamScope board not detected ok Or BeamScope head not detected What has gone wron
15. INTERPRETING THE RESULTS Sanity checks Interpretation of any set of results must be done carefully Perform a few sanity checks on the results For example m Do the calculated source dimensions and distances make sense If the beam overfilled the lens or the slits then the results will be imperfect If the beam is elliptical does this show in the results and displays If not was the laser accurately aligned with the slits BeamScope P5 5 7 5 3 5 4 M Accessory Q If the M2 values are much higher or lower than expected double check your setup Perhaps the results are correct but if the beam was not centered on the lens and on axis then measured M2 values will be worse than actual values 5 8 BeamScope P5 CHAPTER SIX 6 2D SCANNING STAGE 6 1 INITTAL SETUP uccann oa ao 6 1 6 2 OPERATION eette Rr E E ia 6 2 6 3 FREQUENTLY ASKED QUESTIONS 0 0c cccccccesseseeesesceeeeetenseseeeeseseseesesetenseeeeneeen 6 3 This Chapter assumes familiarity with BeamScope PS If you are not familiar with BeamScope read the earlier parts of this manual before reading this chapter 6 1 INITIAL SETUP See page 6 4 for the schematic set up To access the 2D Stage screen press Alt F9 or select TwoD scan Alt F9 in the Options pull down menu Click on TwoD Scan press to setup to open the TwoD Scan Setup dialog box Initially Auto Width should be checked Once you have determined the beam dimensions and locat
16. Profiler DataRay Inc reserves the right to make changes to this manual and to the equipment described herein without notice DataRay has made considerable efforts to ensure that the information in this manual is accurate and complete However DataRay will not be liable for any technical or editorial errors or omissions made herein or for any incidental special or consequential damages of any nature resulting from the furnishing of this manual or for the operation and performance of equipment in connection with this manual DataRay retains copyright to the contents of this manual Purchasers of the DataRay product s described herein may make up to two photocopies of this manual for use in conjunction with the equipment No other copying for any purpose is allowed without the express written permission of DataRay Inc Boulder Creek California BeamScope Beam R BeamMap ColliMate and WinCam are trade marks of DataRay Inc Windows 95 98 NT and 2000 are trademarks of Microsoft Corporation Pentium is a trademark of Intel Corporation 1 4 BeamScope P5 Introduction 1 5 PRODUCT SPECIFICATIONS N B All product specifications are subject to change without notice Measurable Sources CW 1 5 Pulsed sources gt few kHz PRR Pulse Repetition Rate Higher PRR is better Low PRR lasers require a high duty factor 10 or higher Wavelength Range Silicon Detector 190 to 1150 nm Germanium Detector 800 to 1800 nm Indium Arsenid
17. Size 6 00 um it516 Fic Dpiom Log Sep Paota Heip Cicely xe r R _ patel Aim TI EMO sex 7 K 0 975 0 042 0 877 0 029 MA2 1 026 0 044 1 140 0 038 dol 53 070 59 660 Waist 79 697 79 326 CHI NC 5 1 122 24 4 umidi 122 131 26 2 umidi 131 Span Ap 4679 Ap 4679 Offset 0 2 In Show 3D M2 Plot display mode Page Up Page Down keys scroll through the actual individual measurements taken Experiment with the other display options Displays carant scanring status Sf ar 2 and Active or StandBy 3 Working from top to bottom the results are shown in X value Y value format M 2 Wavelength 0 6328um K 0 975 0 042 0 877 0 029 M42 1 025 0 044 1 053 0 041 Waist diameters dol 53 070 59 660 Waist positions Waist 75 322 75 588 The Extended data display option accessed by left clicking in the lower left panel shows RI 79 843mm 80 015mm Beam radius of curvature after the lens DU Rs 1236 515mm 1196 726mm Beam radius of curvature before the lens Do 0 7146mm 0 7397mm Calculated source waist diameter Zofslits 684 89mm 621 91mm Calculated distance from source to slits BeamScope P5 5 3 M Accessory 4 In order to take actual measurements you will need the optional M Accessory DataRay Part Number M2B or the older M2A stage The M Accessory works in conjunction with the BeamScope P5 to measure M in accordance wit
18. Y point 0 O units v Auto Scale On _ Flip Horiz _ Flip Vert um is 10 mm out from the point at Rotate 45 0 degrees Slit Orientation which probe exits the head Background Blip Color Text Color i Check the Lock resetting of the zero Copy zero copies the Zero Merce Point settings into the Absolute settings The Reverse X Y Negate X etc check boxes allow the user to change the orientation of the position vector in the beam wander display It is used with particular Circle Color bright green and Blip Color rose gives a better looking display 4 2 7 Gain and Power Button Gain is the amount of amplification both electrical and software derived required to display the profile the Gain Log10 default being in normalized form This gain is expressed 22 77 23 79 dB in dB 10 log10 of the linear value of the gain In many Power 4 78 mW instances it can be helpful to turn off the software Las normalization To do this press F6 and uncheck the Normalize Profiles box in the upper right of the Full Scale 5 mW dialog box The user can set manual gain if so desired Contained Power Press Alt A to open the dialog box 94 45 94 27 As it relates to the BeamScope Power is a purely relative measurement based entirely on the user s input which is assumed to be correct BeamScope P5 4 11 4 2 BeamScope Functions Use a separate calibrated optical power meter to determine the total be
19. a quite large movement of the beam This is only meant to show you how Centroid works It is NOT normal for most beams to wander that much Press the Page Down key and the Centroid values should return to zero Note that X amp Y are in the normal sense as viewed by an observer travel along the axis of beam propagation i e ve X is to the Right and ve Y is Up assuming that the head is oriented with the faceplate label letters upright 3 1 4 Beam Wander and Absolute position The Absolute button references the beam centroid to a position that you can set as your absolute reference Click in the target like area beneath the Absolute button in order to open the dialog box There is a set of edit boxes labeled Absolute where you set the point that you wish to define as the absolute position For convenience for now press the Copy zero button to make the current zero point the Absolute point You can first record the absolute point and re enter later if you choose The Wander screen shows the position vector traced from the center of the display to the dashed crosshair which indicates the beam center The dashed ellipse indicates the 13 5 intensity contour of the beam profile Clicking on the arrows either side of Zoom changes the displayed area If the Auto Scale On box is checked See Wander Setup Information in Section 4 2 6 the arrow zoom is disabled See Sections 4 2 5 and 4 2 6 for more detail including how to change the colors of the
20. are no other drivers or components to be installed See Section 3 1 to see how the software works Congratulations You have successfully completed BeamScope Installation Go to Section 2 5 WARNING Never hot connect or disconnect the head while the software is powered up This can cause damage to the head and or the PC card electronics BeamScope P5 2 5 2 3 Installation 2 3 2 Installation under Windows NT 1 2 3 4 5 6 7 8 2 6 You must be running NT 4 0 with Service Pack 5 or higher We do not support older versions You must install BeamScope software as Administrator User with Administrator Rights may not be enough If you cannot even install the software it may be that your NT Administrator i e the person has restricted your software installation rights and must therefore be called in to install the software Double click the BeamScope icon to start the software If the BeamScope software refuses to work or it works once and then quits you can thank Microsoft for making NT much too fussy Here s what you need to do With BeamScope closed make sure that the file totalio sys is in the WinNT root directory Use Explorer to verify and or copy it there or in DOS type copy bscope5 totalio sys WinNT then press Enter In the Control Panel there is an Icon called Devices Double click it to open the following dialog Startup Disabled amp Disabled D
21. data for your instrument DataRay technical support can then view the data as you see it Email the result to support dataray com with your commentary Then call O If User Manual authors had their way If you read this manual first you are entitled to free product support by phone fax or email For those who decide not to bother to read this manual before calling for support a 1 900 Help line charged at a per minute rate is available Seriously though read this manual to enjoy the full benefit of your investment BeamScope P5 Scanning Slit Beam Profiler User Manual Serial Number Purchased by Date Rev 0108A 2001 DataRay Inc All rights reserved DataRay Inc 605 Stapp Road Boulder Creek California 95006 USA Corporate Office 831 338 9055 e Fax 831 338 9098 info dataray com e www dataray com Product Support 303 543 8235 e support dataray com Table of Contents LT INTRODUCTION wu csssssssessscscssssssesssssssessnsessssssesesessssssessssssssnsesessesssesessesesesessoseses 1 1 1 1 WELCOME sirio elio abilita 1 1 1 2 FUNCTIONAL DESCRIPTION vise sciseieceses sdecizsecesassviass st edesadscsisavacectesnesnevescanssasdeoneveaeiesest 1 3 1 3 MANUAL CONVENTIONS Aaea ere Aaa io 1 4 1 4 MANUAL AND COPYRIGHT NOTICE criiii ie 1 4 1 5 PRODUCT SPECIFICATIONS 33 oii sss scssscedsesesepeceess cokers sceaseadsterssecersenseageveseaas Aas 1 5 1 5 1 Computer Requirem
22. edges that is the intensity of a perfect Gaussian never actually falls to zero at large distances from the center This arises from the nature of the circularly symmetric Gaussian intensity profile Normalized Gaussian Intensity Profile Im be a E eww TW 0 8 Where ris the radius 0 6 w is the radius at the point at which i the intensity has fallen to 13 5 0 4 1 e of the peak value P is the total power in the beam 1 e 0 135 Replace r by x y and consider the profile 0 at constant x and varying y It is apparent that 2 0 1 0 0 0 1 0 2 0 the shape of the profile is Gaussian wherever a r w cut is taken across the profile It is this principle which allows slits and knife edges to be employed in the measurement of beams which are close to Gaussian 4 2 Beam Irradiance In order to assess whether the irradiance W mm from a given laser might overload a beam profiler it is useful to be able to calculate the peak irradiance From equation 11 the on axis irradiance at r 0 is given by IO 2P mw 2 6P 2w W mm for diameter 2w in mm For example e The peak irradiance from a 1 mm diameter 10 mW HeNe is 26 mW mm e The peak irradiance from a 5 mm diameter 5 W NdYag is 520mW mm 4 3 Second Moment Beam Diameter Conventionally beam diameters have been measured at the 1 e intensity point i e at 13 5 of the maximum intensity For the reason outlined in section 2 2a ISO 11146 mandates the use of
23. i When Stage Setup box appears select your stage and click OK The M screen will appear If the Stage Setup box does not appear press Ctrl S to view the box Part Scan Range Step Size default 1 M2A 20 mm 44 3 um default 2 M2B 2DSS 45 mm 3 5 um default 3 M2C 2DSSC 45 mm 2 5 um BeamScope P5 5 1 M Accessory 5 1 NEW M ACCESSORY USER If you are already familiar with the M software go straight to Section 5 1 2 If not first view a sample data file by clicking on Recall M2 and double clicking samp1 m2 in the Open dialog box You should see the screen shown on the next Show plot M2 waist page As the software version evolves and Show plot M2 waist with extended data dependent on the last configuration saved Show 3D M2 plot minor differences in appearance may occur Show 3D M2 plot with extended data Right click on the turquoise blue graph area Estendi rita to access the display options shown right 1 If the Prompt shown appears click OK RSM x and fill in the Head Setup and Options dialog box right for Wavelength Dlens sono ti bia X Y Focal Length and Lens to slits nearest distance 0 6328 1000 1000 75 amp 65 H Squared Input Parameters Wavelegnth um Dlens X Y 1000 00 1000 00 _ Reverse stage direction Focal length mm Lens to slits nearest distance 65 0 mm 5 2 BeamScope P5 MP Accessory BoamScope ri ti SAMNPI M2 82 of 92 Sin
24. is not already displayed left click the lower central box and select Variance second moment in the dialog box Similarly the top line is normally set to a Clip Level of 13 5 Unscrew the lens and set it to one side Press F4 to search for the profile and then F1 to start a measurement Use the Average Widths N 10 function under Options to take a ten reading average Enter the measured X and Y values as DLens X Y in the Head Setup and Options Screw the lens back on again and reset the Average Widths to No averaging Press F4 to search for the profile and then F1 to start a measurement let it run for about ten measurement cycles to stabilize and then press F2 to halt the measurement Now click the START M2 button A confirmation box will appear Check its contents and click OK The button will change to a STOP M2 button and the M test will begin The software will test the X and or Y axis depending on the current status state As the M scan proceeds the software will calculate and display the results The developed waist will be shown in the chosen 2 D or 3D view A red warning box may initially appear Error Invalid impossible results Verify Wavelength Slits and clip level BeamScope P5 10 11 YY 12 MP Accessory Indicating that the software has not yet found a convergent solution for M ie the largest reading is not yet adequately greater than the smallest The box normally disappears fairly quickly
25. may be activated by clicking the left right or both mouse buttons As the cursor passes over such button areas a Help hint is presented at the bottom of the screen A high percentage of questions are answered by this on screen Help Hint information For example the Beam Wander button area shown actually contains five distinct buttons Zero Absolute Zoom In Zoom Out and a general button in the Beam Wander area User parameters may be set in a secondary dialog box which may be opened by clicking on the Beam Wander button area See section 4 2 6 over the page BeamScope P5 4 9 BeamScope Functions 4 2 4 Ellipticity Button Ellipticity is defined as the deviation of an ellipse or from the form of a circle or a sphere Ellip XI 13 5 As it relates to BeamScope Ellipticity is the ratio of 0 982 the chosen diameter measure Clip Level Variance or Knife Edge as measured by aperture 1 and aperture 2 4 2 5 Centroid Button The calculated X Centroid Y center of mass of the current profile is referenced to the Absolute X Centroid Y point 0 0 units um 10 mm out from the point at which probe exits the head or to the user defined 17382 430 zero point set by pressing the Zero button Hai eo n Zero Absolute The initial values shown indicate the position of the centroid along the scan axis The user would normally then click the Zero button in order to determine centroid position relative to some re
26. n accumulated samples The profile buffer holds the nth n 1 th n 2 th etc averaged profiles up to the buffer limit of 100 profiles It does not hold the raw profiles Click Disable to stop Accumulation Averaging Click Clear to clear the buffer location Average Dialog CTRL V Disabled Opens the Beam Width Averaging z dialog box this is similar to the Bram Wuth Averaging i Accumulation Averaging but includes calculation of the Standard Widths Y Error in the Mean See page 4 4 for a running average 0 00um Clipi 0 0 0 00 um See also Section 4 3 2 Log Menu 0 00 um Std Dev 0 00 um The Max Min Mean and Standard Deviation of Beam Diameter 0 00 um Clip 0 0 0 00 um Centroid Position and Power are calculated and displayed on graphs of 0 00um Std Dev 0 00 um the logged data Samples 0 4 20 BeamScope P5 4 3 2 Log Menu Log Data to Hard Drive First set the Update Interval password protected if you so choose in the Pass Fail dialog box Section 4 2 1 Click on CAPTURE ENABLE IS OFF or NEW to open a Save As dialog box which allows you specify a filename BeamScope Functions Log profiles to drive Ed File Captured profiles 0 File Size 0 and location Click OK The button will change to CAPTURE ENABLE IS ON Enter F1 to start the scans amp data logging F2 stops the scans 4 3 Analyze Profiles Click on Analyze profiles to open a BeamScope Data
27. of the 2 region The scan regions should never overlap along the horizontal axis 3 It is possible for the Auto Search function to mistakenly place the X and Y scan areas at the same location which may or may not be desirable Sometimes the software will allocate Ap3 and Ap4 The user must overwrite this as follows e Click and drag to move a scan region manually to the desired scan region e Define a new scan region by placing the cursor outside the gray region and clicking and dragging a new region with the mouse When the mouse button is released a menu will appear asking to Set Ap2 which aperture the defined region should be allocated In the current release only allocate Ap1 or Ap2 to scan regions Set p3 Warning To ensure valid results the entire profile must be within the scanned area sa J 4 Double click on the lower part of the search area to cycle the size of the search display from normal to large to minimum and back to normal 3 12 BeamScope P5 Quick Start Tutorial 5 Press F1 to start the scan and look at the profiles Press F2 to stop the scan 6 Performa sanity check Does what you observe make sense If so great it is almost certainly correct If not then the most likely problem is the scanned region Reread the previous section and be sure that you understand it If all is fine repeat Section 3 2 2 above and verify that all the correct options have been checked If the beam is much smalle
28. slit width is made The red Gaussian profile is the fit to the calculated profile width 4 28 BeamScope P5 BeamScope Functions 4 6 GAUSSIAN FIT ALGORITHM Shown is a typical pair of beam profiles with Gaussian Fit profiles overlaid in red Whether in linear or in logarithmic mode the displayed beam profile is always the raw data taken by the detectors Processing described below only determines the displayed Gaussian profile and the Gaussian fit X Apl 45 deg Y Ap2 45 deg LTA ET ETT RRR REE BRR ieeee BERR REE RRR TTT RITA TT ETT TT EERE ER VANE NONE NANA BREE sE IENE KANE IE TEEN e AHH ELENEN m E inizia sazia 44 8 9 um div 44 44 8 7 um div 4 6 1 Gaussian Fit Algorithm The Gaussian Fit is calculated as follows Formulae are given for x only In Knife Edge mode the software first differentiates one edge of the raw profile in order to create a beam profile exactly analogous to that taken with a slit 1 2 3 The software determines the peak and minimum background levels in the raw profile lrawp x It then subtracts the background level to generate a revised data set called Ip x The peak position Xp value Ip xp and beam diameter at the 13 5 points 2Wp are determined Initially all points below 13 5 of peak are ignored to give position Xp and value I p xp Then having defined I p Xxp Xp and lp Xp are defined by ignoring all points below 2 of I p Xp In subseque
29. source far field full angle divergence Calculate amp 2W0 0 E g for a typical laboratory HeNe diameter 2Wo 0 8 mm divergence 1 mrad z 800 mm This source to lens distance is ABSOLUTELY CRITICAL If it is not observed near field anomalies WILL lead to false values of M ai press the button shown to bring up M_ 2 Wavelength 0 6328um the Head Setup and Options dialog box and enter the correct wavelength in microns in the M Squared Input Parameters section If the wrong wavelength is entered the M result will be wrong In the M screen the rectangle shown here displays the position of the M stage While the M is not scanning placing the cursor on a location on the bar and clicking BeamScope P5 MP Accessory the left mouse button moves the stage to that location You can use this feature to setup for the M scan e g to verify that the locus of the waist centroid is not skew 200 mm 8 0 7 HOME the stage and physically verify that it is at the BeamScope Head end of its travel If necessary press Home two or three times until the stage stalls at the BeamScope end Press f2 to stop the stage once it stalls If the stage position bar is at zero but the stage is at its furthest from the BeamScope s slit open the Head Setup dialog box press F6 and click the Reverse stage direction check box and click OK Click the HOME button again and verify that the stage is at Slits end of its tra
30. to display this fact in real time This makes BeamScope an ideal tool for use by non technical staff in QA and Production Test The outer set of buttons displays the calculated beam diameters in microns UM or millimeters mm as selected in the Pass Fail Parameter Setup dialog box The beam diameters on the left corresponds to Aperture 1 profiles normally designated X and the right to Aperture 2 normally designated Y A bracketed number e g 10 after the reading indicates that the reading is being averaged In this example it would be the average of the last ten diameter readings Pass Fail can be set for all JESSE GEE UE So displayed parameters Enter Alt S P to access the Pass Fail Parameter Setup dialog box and change the upper left hand Apl 13 5 00 00 vi corner to read as shown Apl 13 5 00 00 600 00 ja il Ej Beam Width Parameters Maximum test Click OK and note that the lower Ap2 13 5 400 00 1900 00 left beamwidth result is now 00 00 displayed in red because it failed Ap2 13 5 400 00 1 the Maximum Beam Width criterion wo som 3 3 3 n Right click on this result and then click on the red color patch to see how to choose a different color 3 6 BeamScope P5 Quick Start Tutorial 3 1 7 Included Power and Distance Measurements on the Profile Enter Ctrl 3 and x to display the x profile only Put the cursor to any point on the plo
31. 5 Max 593 9 Mih 589 4 Mean 592 7 Std Emor h Waan 0 49 3 14 BeamScope P5 Quick Start Tutorial 3 2 6 Short Cuts Note the following Short Cuts As the cursor moves watch the Help Action Line at the bottom of the screen Try every Short Cut key now See Section 4 for full descriptions Starts a scan Repetitive Search Stops a scan Scan Head Set Up Single scan Aims Head Searches for signal Opens Profile Log 3 2 Selects both profiles Exits the program Selects x profile only Toggles Angular width and normal width Selects y profile only i Reconfigures for a Pinhole scan Shift R Recall amp Process profiles o Opens Auto Manual Gain dialog Page Up Access the previous profile Opens the Accumulation Page Down Access the next profile Averaging dialog Toggles between profiles only and also showing the 2 D and 3 D views Opens the Program Head dialog rarely required Toggles between Geometric and Centroid based centroid definition Opens a Job file Reconfigures the screen for M measurements and toggles back to Normal Opens the Slit Orientation Dialog box Opens a dialog box for setting up the Auxiliary stage motion Screen dump to clipboard Image does not include the Button Bar Menu and Page Header above or the Help Notes and Task Bar below Opens the Average dialog box Opens the Slit assignment dialog box BeamScope P5 3 15 Quick Start Tutorial 3 16 BeamScope P5 CH
32. APTER FOUR 4 BEAMSCOPE FUNCTIONS 4 1 THE MAIN SCREEN Quooe cccccccccssccsssecescecesssccsssscessecesssscsssscessscesssccssecessssesssccssuscessssesssscees 4 1 1 Pull Down Menus 4 1 2 The Button Bar Sh 4 2 MAIN SCREEN SECTIONS s see creerere ee eee ee cerca rire ee cere cere eee eee 4 2 1 Pass Fail for QA and Production Testing 4 2 2 Button Colors Setup 4 2 3 Button Areas and Help Hints 4 2 4 Ellipticity Button iii 4 2 5 Centroid BUtton i ee 4 2 6 Beam Wander Butioni 3ss anello 4 2 7 Gain and Power Button 4 2 8 Gaussian Fit BUtton i 4 2 9 Head Statistics ali aaa ASD TO 2D View buttoh siae ROL lane 4 2 11 3D View Button seere ira nii aia e Ea a a Eai 4212 Beam Widths BUttONS oeras aLaaa 4213 Beam Profiles Ared inca 4 2 14 Search 4 3 PULL DOWN MENUS ADDITIONAL DETAILS iii 4 3 1 Opuons Meniki sici alla AGR E RIE 4 3 2 Log Mentana ERG ELIS Ania 4 3 3 Setup 4 4 SLIT MODE 4 5 KNIFE EDGE MODE 4 6 GAUSSIAN FIT ALGORITHM 4 6 1 Gaussiar Fit Algorithm incci na ibn i BeamScope P5 4 1 BeamScope Functions 4 1 THE MAIN SCREEN Double click on the BeamScope icon to open BeamScope Below is the view of the Main Window of the BeamScope P5 software From time to time there will be changes and additions to the software However the latest version will always
33. BEAM P5 A 14 Size of this structure scan direction 0 left to right 0 x 1 y 2 z number of data samples max ADC value before base removal max value after base removal 4 0 MHz MotorSpeed clocks per second 4 0 MHz AdcRate clocks per second 0 not valid Range of log input ie 0 to 34 6 dB Was if true an old type BEAM has been data proccessed not used 4096 for 12 bits old 0 1 4 phase 2 5 phase Gain used to get data 200 20 0 db log10 one or two very important for width calcs 5 0 um typical used internally center of scan in microns referenced to full scan Span in microns Span in microns Step Size in microns used to calculate widths position motor started for data used internally position motor started for data used internally position motor ended for data used internally weighed center in samples not microns A unique identifier M 2 position in steps may be used for expansion start point of samples BeamScope P5 Appendices The beam data structure s are prefixed with the following header typedef struct header for BeamScope data files char lead 35 must read BeamScope Beam Data P5 char Time 35 time date is was saved WORDSize 2 __ size of the two BEAMS Il one may be zero or sets of Beams BEAMHEADER To read a file follow
34. BeamScope BeamScope BeamScope BeamScope BeamScope BeamScope BeamScope BeamScope BeamScope BeamScope BeamScope BeamScope P5 Scanning Slit Beam Profiler User Manual Very IMPORTANT This information is here so that you cannot miss it If you received the ISA card version but cannot use the ISA card version you may return the unit for a full refund The PCI card version will be available in early Q4 2001 If you decide to keep and use the ISA card version and you purchased the unit on or after January 1 2001 you may upgrade to the PCI card version for 500 US List Price as soon as it becomes available Using an older BeamScope P3 Contact us for a P5 upgrade deal at 50 off Q Do not hot plug or unplug the head while the software is on You may damage the unit Do not accidentally plug the monitor cable into the DataRay PC card To avoid slit damage observe the maximum irradiance limits section 1 8 2 If the software appears to be giving errors load the defaults by holding down the Shift key when you start the software The beam should be centered on the instrument for the most accurate measurements If you get a result or inconsistency that you do not understand before you call proceed as follows Via the Pull down menu go File Save to save the single profile set or to save a sequence of data particularly if you are seeing instability The saved file dat format includes some setup
35. E This is the normal mode of operation for the BeamScope A slit narrower than the beam diameter is employed to measure the beam diameter The slit should be at least a factor of three smaller than the beam being measured To strictly meet the ISO 11146 standard use a ratio of 1 20 for slit width beam width and 2 for slit height beam width In addition the average of five beams should be taken When the slits are set in their normal mode at 45 to the probe scan direction the software automatically multiplies the width of X Y slits entered under Slit Size in Head Setup and Optionsby a factor of 2 When the slit width approaches the beam diameter software correction should be made for the slit width DataRay automatically compensates the diameter readings for slit 4 4 diameter If this is not done the error is nearly 5 for Gaussian beams when the slit width to beam diameter s 2w is 25 of the 1 e beam diameter A simple correction difference of squares for slit width reduces this error to 1 35 DataRay s algorithm reduces the error to lt 0 1 and to 1 at s 2w ratios as high as 0 70 Error versus Slitwidth Beamwidth Ratio 20 Difference of Squares Corrrection 13 5 Clio gt 15 10 5 Formula Formula 50 Clio NA 13 5 Clio 0 x Difference of Squares Corrrection 50 Clip 5 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 Slitwidth s Beamwidth 2w
36. GXY5 Probe Style Head Germanium Detector with XY5 5um Slits 3IXY5 Probe Style Head Indium Arsenide Detector with XY5 5um Slits 3IRXY5 Probe Style Head II VI Detector with XY5 5um Slits XS 4GXY5 4ixys5 4IRXY5 Rotatable Head II VI Detector with XY5 5um Slits EPH Appears after the head P N for the 30 mm Extended Probe Head Accessories Part Description BeamScope P5 2 1 Installation M2B or M2C M2 AAP M2 BP 2DSS or 2DSSC 2DSS AAP BP1 RHMB1 FieldPack BS CAB BS CABS 3 0 BS CABS 4 5 PAS PA10 PA25 SS2 5 SS5 SS10 SS25 XY2 5 XY5 XY10 XY25 XY100 XYPI2 5 XYPI5 2 2 MP Accessory 3 m long high current cable with RJ 45 8 pin connectors M2 AAP BP1 M Accessory Adaptor Plate Screws Attaches M Accessory to BeamScope M BasePlate 2 adjustable mounting posts 2D Scanning Stage 3 5 mm steps 45 mm travel 3 m long cable with RJ 45 8 pin connectors 2DSS AAP BP1 2DSS Accessory Adaptor Plate Screws Free with 2DSS Attaches BeamScope Probe Style Head to 2DSS Accessory BasePlate Free with M2B or 2DSS BasePlate is 6 x 12 x 1 inch with 3 rows of 1 4 20 holes at 0 5 pitch Rotatable Head Mounting Block Screws Attaches the BeamScope Rotatable Head to 1 pitch 1 4 20 holes FieldPack enclosure for PC BS5 PC card power supply 2 m long parallel port cable BeamScope BeamMap Beam R spare cable 3 0 m 10 ft long Triple shielded BS CAB cable 3 0 m 10 ft long Tri
37. a Second Moment definition of beam diameter 2W Z 2V2 0 z 12 A 10 BeamScope P5 Appendices where the variance oz is calculated as 7 free z r dr do 0 2 I r z r dr dd 13 Where I r z is the radial intensity distribution versus angular position along propagation axis z In more useful x and y terms since these are what actually get measured o 2 JAM y 2 dxdy i x y 2 dx dy _ Jf yxy zaxay I x y z dx dy oy 2 2Wox Z 4 0x Z 2Woy 2 4 0y 2 1 xy denotes the centroid of the I x y z intensity distribution The ISO 11146 standard actually terms the quantities E x y z rather than I x y z and dox z amp doy z rather than 2W z amp 2Wo z Here we have used the more familiar terminology rather than the less common terminology used in the ISO standard For a pure Gaussian intensity distribution the second moment width is identical to the more familiar 1 e 13 5 of peak intensity width There are a number of potential disadvantages to the use of second moment as a beam diameter definition none of which are insurmountable in a well designed system a Unless the results are gathered and processed automatically the second moment diameter is non trivial to calculate It is not possible to simply measure it directly from a graphical plot of the data b Any unsubtracted background in the wings either purely analog noise or quantizatio
38. ad See Section 4 3 2 Assign Slits CTRL X Designates which slit corresponds to which axis See Section 4 3 2 Program Head EEPROM CTRL E Allows the user to reprogram the EEPROM in the head There are almost no circumstances under which this is required Contact DataRay before changing anything See Section 4 3 3 Setup auxiliary stage CTRL S Allows choice between the two auxiliary stage motor drive defaults Choose default 2 unless specifically instructed to do otherwise BeamScope P5 4 5 4 1 BeamScope Functions Palette Lets you choose the number of displayed colors e Use 10 color for 10 increments e Use 16 color or 256 color for more level resolution Gray e Use Gray for black and white printing v 16 Color e Use Last loaded sets the palette to that of the most recently 10 Color loaded file Last loaded Help Opens the BeamScope P5 Help system which is essentially an online version of the BeamScope P5 manual The latest revision may be this printed manual rather than the program s Help file 4 1 2 The Button Bar The Buttons are an extension to the Menu System They are all activated by clicking with the mouse ReMax ko mmp El CEI SI 2 Clears screen data and data buffers Recalls previously saved profile data or M2 data sets Initiates the save data procedure which allows you to save one highlighted profile or all current profiles Sets the BeamScope P5 to display profile X fr
39. am power then enter that power by clicking on the Power area to open the Power Calibrate Dialog and entering a value and unit e g 4 78 amp mW The BeamScope P5 software will monitor any subsequent changes in power even if the beam diameter varies However no claim is made or implied that the BeamScope PS is a calibrated and or reliable power meter The Contained Power is the power within the limits defined by the Clip Level shown in the lower center of tte Beam Widths area If Variance var is chosen the clip level is automatically set at 13 5 Note that the contained power percentage within any limits may be measured on the beam profile display area by clicking and dragging the mouse across the screen See sec 4 2 13 4 2 8 Gaussian Fit Button A laser beam operating in the TEM mode has a Gaussian profile and many more complex beams Gaussian Fit have profiles close to Gaussian 0 967 0 965 Gaussian Fit is the calculated agreement best fit expressed as a fraction or as a percentage of an ideal Gaussian beam For information on the calculation of Gaussian Fit percentage function refer to the Gaussian Fit Calculation Section 4 6 of this manual Click on the button area in order to toggle between enabled and disabled Gaussian Fit To change from to fraction enter Alt S P to access the Pass Fail Parameter Setup dialog box and choose Show as factors 4 2 9 Head Status This is only used to indicate
40. an M of around 1 1 to 1 2 rather than the 1 0 of a perfect TEMoo beam At its simplest M may defined as The ratio of the divergence of the actual beam to that of a theoretical diffraction limited beam with the same waist diameter A prerequisite of M Squared measurement is the availability or creation of an accessible beam waist Referring to Figure 1 BeamScope P5 A 3 gt 5 N m DOT Appendices Figure 1 M The Embedded Gaussian Concept Actual Beam M gt 1 Normalized Beam Diameter 2W z 2Wo Embedded Gaussian M 1 4 0 2 0 0 0 2 0 4 0 Normalized Distance z z p from Beam Waist ab Where The measured farfield fullangle divergence of the actual beam The theoretical far field divergence of a perfect TEMo Gaussian beam which has the same waist diameter as the measured beam And since g_ 2 sti TWo Where 2Wo The beam waist diameter The measured beam waist diameter must be the second moment definition of beam diameter see Section 3 5 3 Substituting 2 into 1 gives y2 _ Li Jo Wo 3 An The shape of the M curve may be shown to be hyperbolic of the form Where z is the Rayleigh Range which is defined as the distance at which the beam diameter is V2 greater than the diameter at the waist zr may be shown to be _ 2Wo _ z 5 m a age a A 4 BeamScope P5 Appendices Rearrangement of equations 3 to 5 gives a redefinition of M in
41. an that set by Auto Search The plot options box also gives access to the background color and vertical grid commands and to sometimes useful functions such as Use thick pens slower to give more visible profiles at the expense of processing speed Plot history superimposes successive profile plots useful for indicating the level of noise in noisy lasers or e g to show the envelope of the profile change as a laser warms up See Section 4 3 1 for a discussion of Accumulation Averaging which produces an averaged profile useful for averaging noisy profiles 4 16 BeamScope P5 BeamScope Functions 4 2 14 Search It is CRITICALIY important that you properly understand this section Read it at least twice Span Ap 1060 Ap2 1798 Offset 11588 In Search mode the probe determines the location of the beam to be scanned 1 Click Aim to move the probe out and aim the beam at a point on the probe 10 mm out from the head Then Press F4 to instruct the probe head to search for the beam TIP To align the beam with the slits Press F5 to perform repetitive searches then F2 to stop the search once successfully aligned as defined in 2 through 5 below 2 Whena Search has been performed inspect the search display reproduced above and verify that the scan regions found by the search routine make sense The X slit Ap1 and Y slit Ap2 scan regions are indicated as dark gray regions marked 1 and 2 T
42. any time you may download the latest version of the software and or this manual from our website at www dataray com Visit the site in order to determine whether an update is available and the revision number of the current version DataRay is committed to providing the ultimate in beam profiling perfornance and welcomes constructive criticism on its products and on this manual Contact us at the addresses or numbers shown on the title page of this manual If you need a function that is not included in the current version of BeamScope PS please fill out and fax a Function Request form found in Appendix A of this manual or email support dataray com Many requested functions can be added with relative ease and may be done for free and possibly added to future releases However if the requested embellishment is considered extensive and or obscure DataRay reserves the right to quote and charge for the requested change Warranty Standard product warranty is three years from the date of shipment this warranty excludes customer damage to the unit Calibration Recalibration services are available Please contact DataRay or your local Distributor 1 2 BeamScope P5 Introduction 1 2 FUNCTIONAL DESCRIPTION BeamScope P5 implements slit profiling in accordance with the ISO 11146 standard by using a linear slit scan probe to sample the beam The following is a brief description of the working principle Q The BeamScope scans a slit
43. atic damage contact the bag in which the card is packed to the computer metalwork before removing the card and immediately placing it in the computer Carefully hold the BeamScope P5 card by its top edges and guide it into its expansion slot Ensure that the BeamScope P5 card sits firmly in the slot Secure the BeamScope P5 in place by fastening its metal bracket to the computer frame with screw Replace the computer cover Connect the supplied 15 pin D connector cable to the BeamScope P5 card WARNING The BeamScope cable connector is the same type as an SVGA monitor cable and MUST NOT be inadvertently misconnected to the video card If you are also installing the M Accessory or the 2D stage you may also connect the 8 pin RJ 45 network like cable to the BeamScope P5 card Also attach the cables to the BeamScope head and if present the M Accessory or the 2D stage Reconnect previously disconnected power cords Power up the computer WARNING Never hot connect or disconnect the head while the software is powered up This can cause damage to the head and or the PC card electronics BeamScope P5 2 3 2 2 Installation 2 3 SOFTWARE INSTALLATION This software does not run under Windows 2000 An upgrade with PCI card for Windows 2000 will be available in Mid 2001 It is recommended but not necessary that PC cards are installed before the software The software can be used to view data whether or not the BeamScope P5
44. aussian profiles is determined by setting the taller profile to 100 To normalize both profiles to 100 disable Auto Gauss Peak Finally the measured width is compensated for the width of the slit as described in Section 4 4 Note 4 30 The Pass Fail criteria are the only user set Gaussian Fit parameters The Gaussian Fit peak is not always at the same position as the object profile peak The Gaussian Fit peak is always at the same position as the object profile centroid The BeamScope P5 algorithm avoids assuming that the object profile peak position is identical to the Gaussian Fit peak BeamScope P5 CHAPTER FIVE 5 USING THE M ACCESSORY 5 1 NEW M ACCESSORY USER csccccssscccsssecssssecssssscssssvessssuesessuecssssecssssessesascessscessssecssssece 5 2 5 2 M2 HARDWARE SETUP P aaa a a a a eaei Eeoa R N aeania 5 3 OPERATION rien 5 4 SAVING amp PRINTING THE RESULTS 5 5 INTERPRETING THE RESULTS rire eee eee This Chapter assumes familiarity with BeamScope P5 If you are not familiar with BeamScope read the earlier parts of the BeamScope manual before reading this chapter Max stage travel Stage step size 3 50000 um default 1 default 2 New cable drive lead srew lead srew Normal Slower Normal Fast Faster If you are unfamiliar with M asa concept see the Appendix B To access the M screen press Ctrl M or select the M42 item in the Options pull down menu
45. be available from the DataRay website at www dataray com 333 1685 cei 0 O33 200 PEE urli O AR TI 1 57171 Cdl eee The functions contained in the individual pull down menus and the main screen sections are described on subsequent pages Note the keyboard alternatives to working with the mouse They can be a much faster route to many useful screens and functions 4 2 BeamScope P5 BeamScope Functions 4 1 1 Pull Down Menus Do not simply read this section Click on each function in turn so that it opens up and so that at least your subconcious becomes aware of and imprinted with the existence of these functions Use and learn the keyboard shortcuts where provided They are listed in Section 3 2 6 page 3 13 a few pages back This will save you much time later File Options Log Set Clear Clear Clears the screen and data buffers Open Open Opens a saved data or M file Save 41 Save Saves current data either active or Open Job Ct J Save file as type recalled in all in part or as Save Job selected Beam data dat Print Beam data Data may be saved as a Print with notes M2 file sets m2 txt file and then imported Print Setup Bitmap files bmp into an Excel spreadsheet Enit ALT FA ASCII Files asc by choosing Delimited uit A TEXT Files with Space and Comma as delimiters Open Job CtrlJ Recalls a previously saved Job file Save Job Stores the cu
46. bsolute Ellipticity Orientation of Major Axis Beam Wander display BeamScope P5 1 5 Introduction Displayed Profiles Note 1 Update Rate Data Analysis Pass Fail Averaging Standard Deviation Power Measurement Source to Slit Distance Aperture sizes Note 2 True2D Slits Pinholes Dimensions Probe Style Head Rotatable Head Dual slit separation NA Mounting Weight Probe Style Head Retatablo Head Temp Range including Accessories Operating Storage Minimum PC Requirements Mac version is notavailable 1 6 X only Y only X amp Y 2 D plot 10 16 or 256 colors 3 D plot 10 16 or 256 colors gt 1 Hz typical 2 Hz max Depends upon the PC processor Speed the Scanned Profile amp the Selected Options On all measured parameters on screen in Pass Fail colors Beam Diameter Running Average and Accumulation Average options On Accumulation Averaging Screen Units of mW relative to a reference measurement provided by the user Not a calibrated power meter 1 0 mm minimum Important See Scanned Area above for measurable beam dimensions 2 5 5 10 25 and 100 um wide 7 mm long Planar version of 5 pm slits are 5 mm long 5 10 25 and 50 um diameter Smaller or larger to special order Across axis width x Height x Along axis depth 115 x 51 x 62 mm 4 5 x 2 0 x 2 5 inches Probe fully extended width 140 mm 5 9 Dual slit center to center separation 10 mm Bottom end se
47. cation note modifies that assumption to five times greater diffraction than spherical aberration A 12 BeamScope P5 Appendices Appendix C Technical Support Sales Returns Distributors and Representatives DataRay maintains a network of knowledgeable non exclusive Distributors and Representatives and also offers direct product support As with all companies contact names and telephone numbers vary with time and therefore have not been included here Visit www dataray com for a complete listing The current procedure for returning product is also posted at the website in the On line Support area App BeamScope P5 A 13 Appendices Appendix D BeamScope Data Structures Almost no users will need this information contact DataRay for any updates before attempting to use it The information is given as a courtesy only all associated rights are retained by DataRay Inc The beam data structure is defined as follows name dat or name log typedef struct int Size WORD Direction WORD Axis int Count WORD GainPeak WORD Peak WORD MotorSpeed WORD AdcRate BOOL Valid BOOL LogRange BOOL Converted BOOL Proccesed int Resolution int HeadType float Gain int Slits float SlitSize float StartPosition float Center float Span float SpanCenter float StepSize long DataStart long MotorStart long MotorEnd long xCenter int TotalWidth float TotalArea int32 Key long Position2 BYTE Resv 196 WORDData 2048
48. conflicts with the video card Q3 I tried to print the results and nothing happened Why not Answer Your printer parallel port is occupied by the BeamScope cable and or software Save the BeamScope results file and print out the results after you have taken all the measurements that you need and have closed BeamScope If you are networked via other than the parallel port then you may use a network printer while FieldPack is connected If you have two LPT ports then devote one to FieldPack and one to your printer Q4 Can I install a second parallel port devoted to BeamScope Answer BeamScope is generally intended for use with portable PC Notebook computers which have a single parallel port and no expansion facility so the answer to your question is No If you are networked then use a network printer If you find asecond parallel port third party solution that works please inform us Q5 I started the BeamScope software and a DOS screen entitled Xcopy32 appeared What do I do next Answer This is only true for BeamScope Versions 5 1x and earlier and has been fixed in later versions It was related to NT issues For a permanent solution visit www dataray com support htm download the BSExe zip file and unzip it to the c Bscope5 directory The problem is that you started BeamScope without the FieldPack parallel port cable attached to the parallel port or with the FieldPack power supply disconnected Close out the
49. ction 4 3 1 1 Start the Software See Section 2 2 if the software is not yet installed Double click the BeamScope icon to start the software Notice BeamScope board not detected will appear if the hardware is not present Click OK The main screen display should appear Y Ape 45 deg 453 01685 dh N OSS 208 Pl Sumi N Ane 3 2 BeamScope P5 uick Start Tutorial 3 1 2 Examine previously saved Data Click on this button or Enter Alt F Oto open the Open dialog box select the samp1 dat file and click OK to see the screen below ra Apt 45 deg Y Ape 45 deg ME Bitoni N HE 352 Meanie N Note that the Caption bar at the very top displays the BeamScope P5 software version and the name of the file you just loaded It also states that you are currently looking at profile 1 of 92 The BeamScope P5 has a data buffer that can hold up to 100 profile pairs Finally there is a number 369 in this case which indicates the number of profiles processed since either the software was started or since the last Clear Screen Data and Data Buffers operation was performed X amp Y count as separate profiles There are two methods you can use to change the currently viewed profile Press one of these buttons to move to the next or the previous profile The Page Up and Page Down keys perform the same function BeamScope P5 3 3 31 Quick Start Tutorial gf Clicking on this button opens a dialog box that allows you to vie
50. d good experience using IBM ThinkPad Notebooks with FieldPack A L 2 8 Install the Software From the Application Notes at the website download any version of FPInstall zip dated later than this manual and any User Manual supplements from the site Install the BeamScope software in the Windows standard manner instructed in sections 2 3 1 and 2 3 2 above Change the Shortcut Icon Properties Once the BeamScope software is GESIS sacs BEI installed right click the General Shortcut BeamScope icon on the Start screen Desktop FN BeamScope FieldPack then left click Properties Target type Application If no icon is present on the T getlocation BSCOPES Desktop use Windows Explorer to Target D ADataRav BSCOPES PHASES EXE Ipi find Phase5 exe in the Bscope5 directory found under C if a Statin JDADateRaABSCOPES normal installation was made Shortcut key None Click drag and drop it onto the Desktop in order to create a Bun Normal window a shortcut In the Shortcut folder under Find Target Change Icon Properties in the Target line add a space followed by Ipt and click OK Gai OK to give ox cos CA BSCOPES5 PHASES EXE Ipt For Windows NT add NT to give C BSCOPE5 PHASE5 EXE NT Ipt BeamScope P5 Installation 4 Rename the icon by clicking once then once more on the name to allow it to be edited Suggested names are Fy BeamScope
51. dows at this time please run it now 2 Windows 3 1x Select Run and enter a setup press Enter or click OK 3 Windows 95 98 Press the Start button select Run enter a setup or b setup and press Enter or click OK 4 The install program will allow you the option of changing the name and drive location of the BeamScope P5 software 5 Click the OK button and the install program will do the rest 2 4 BeamScope P5 6 7 Installation O During the last stages of the install program there may be an unsettling extended pause this is normal If this is not the first installation BeamScope Message x there may be more than one BeamScope icon present If so you BeamScope configeration file is may simply highlight the undesired invalid loading defaults icon and press Delete 2 Double click the BeamScope icon to start the program The first time the BeamScope P5 program is run or if a newer version has been installed the message shown may appear It simply warns you that the old configuration file was discarded and you will need to verify your Setup parameters press F6 after BeamScope opens If a JOB file is linked to the icon or shortcut file it will still be attached TIP In the unlikely event that the software ever refuses to start you can force the BeamScope software to flush its configuration file to the defaults by holding down the Shift key while launching the program There
52. e Detector 1 5 um to 3 5 um I VI detectors gt 3 5 um To special order call for delivery Measured Beam Powers See the graph in the Notes below E g 2 uW to 0 7 W for a 1 mm diameter 1 e Gaussian beam 633 nm 5 um slit Optical Dynamic Range 55 dB 300 000 1 75 dB with Neutral Density 2 0 film 3 5 diskette cut out after slit Shape of Maximum Scanned Area Important For accurate measurements beamwidth should be lt 0 5 x Scan Dimensions For the extended probe head dimension 23 mm below becomes 35 mm Shape Cross Scan x Scanned Length Pinholes PA series LineScan Pinhole diameter x 23 mm Single Slits SS series Rectangle 7 x 23 mm 5 for Ge 3 for InAs 1 for II VI C X Y Slits XY series XW Trapezoid 5 x 15 5 mm 3 for Ge 2 for InAs 0 7 for Il VI 3 5 x 13 5 6 5 for 5 um planar slits Rectangle 45 x 23 mm scanned area image Scans a 2 D Stage M2B pinhole over this area Measured Beam Diameters Widths um to 15 mm single slits amp pinholes Defined as the 1 e diameter 13 5 of peak for Gaussian beams Measurement Resolution lt 0 1um or 0 1 of the measured beam diameter whichever is greater Measurement Accuracy 1um 1 of measured beam diameter Measured Beam Profiles X amp Y Linear amp logarithmic profile display modes Measured Profile Parameters Gaussian beam diameter Gaussian fit Second Moment beam diameter Knife Edge beam diameter Centroid position relative and a
53. e button and a floating menu appears Experiment have fun The rotating 3D image is great for display when the V Ps come round but consumes processor power and should not be left on during serious work Double click the 3D image to swap the main pane back to the profiles view BeamScope P5 3 7 3 1 Quick Start Tutorial 3 1 10 Print the Results Click the Print this screen with notes button at top right add some spurious comments and print the results 3 1 11 Other Great Features exist within the BeamScope software including Q The ability to log the data to the hard drive over an extended period Section 4 3 2 Q The measurement of Beam Quality Parameter M Chapter 5 but apart from the short cut keys listed on the next page this is enough for a start Read Chapter 4 to get the complete story 3 8 BeamScope P5 Quick Start Tutorial 3 1 12 Short Cuts Note the following keyboard based Short Cuts and as the cursor moves over the screen watch the Help Action Line at the bottom of the screen Try now using every Short Cut key with a description shown in bold Keys not shown in boldrequire hardware to be present See Chapter 4 for full descriptions Starts a scan Repetitive Search Stops a scan Scan Head Set Up Single scan Aims Head 3 1 Searches for signal Opens Profile Log Selects both profiles Exits the program Selects x profile only Toggles Angular width and normal width S
54. each scanned profile the amplified detector output amplitude is digitized in 2048 levels using a 12 bit ADC Analog to Digital Converter at 2048 intervals spaced equally across the scanned region The software processes the digitized profile to give the data required for display and data logging and feeds back some information to the automatic search routine above The user configures screen functions to implement the measurements in the desired manner BeamScope P5 1 3 1 2 Introduction 1 3 MANUAL CONVENTIONS In this manual click always means left click the mouse button Q double click always means double click with the left button click and drag means left click on the object indicated hold down the button drag the object across the screen to the desired position and then release the button If a right click is required this is clearly indicated as right click select or check means left click with the mouse button press always means press the keyboard key D oO 0 O enter means enter using the keyboard e g Enter Alt F S means press the F key while holding down the Alt key then release the Alt key and press the key marked S Sometimes it is also necessary to finish with the Enter key in order to complete the process 1 4 MANUAL AND COPYRIGHT NOTICE This manual describes the operation of the BeamScope P5 Scanning Slit Beam
55. eam profiling in accordance with the ISO 11146 standard O The 2phase stepping motor in the original P3 version has been replaced by a 5 phase motor with enhanced micro stepping to give a scan speed which is three times faster smoother and more accurate O The kevlar drive band has been replaced by a tensioned stainless steel band to ensure longer life and higher accuracy A PIN photodiode has increased the linear dynamic range Q Improved circuit grounding and other amplifier improvements have reduced the noise floor Relocation of the analog to digital converter has further reduced noise Q Improved four screw slit mounting avoids warping and simplifies aperture assembly replacement Q New True2D sapphire substrate slits with mult metal opaque areas only 0 4 um thick improve the profiling of small and highly divergent beams The P5 software combines easy to use intuitive logic and proven beam profiling algorithms The P5 version is completely new Users of previous versions will not see many similarities However with a little time and patience we think you will be pleasantly surprised with how easy to use we have made it BeamScope is designed to be used as a manufacturing tool that can be easily customized to your application Job files can be linked to the BeamScope Icon dlowing different configurations to be easily launched by clicking on the appropriate BeamScope Job icon BeamScope P5 1 1 1 1 Introduction At
56. eferred Open ISA half slot PCI slot version coming Q4 2000 SVGA or better video system 800 x 600 with 256 colors or better Will work on 640 x 480 but NOT recommended A Microsoft compatible mouse Windows 3 1x Windows 95 98 NT 2000 4 MB RAM A hard drive with 10 MB or more available space BeamScope P5 does NOT use any DMA Direct Memory Access or IRQ interrupt BeamScope P5 does NOT use the negative 12 V power supply available within the PC 1 12 BeamScope P5 CHAPTER TWO 2 INSTALLING BEAMSCOPE P5 2 1 UNPACK THE BEAMSCOPE HARDWARE cccccsssccsssscessesssssccssecessssssssccssuscessssesssseees 2 1 DID PEG GARD INSTALEATIONI Ti ila RL I aaa 2 1 2 3 SOFTWARE INSTALLATION 2 3 1 Installation under Windows 95 OF 98 24 2 3 2 Installation under Windows NT uui 2 6 2 4 FIELDPACK INSTALLATION 2 5 MOUNTING amp STARTING BEAMSCOPE cccccccsssccesscsssssccsscecsssesssssccsseecesssssssssesees 2 1 UNPACK THE BEAMSCOPE HARDWARE Check your purchase If you have any questions contact us The purchased BeamScope consists of the PC BS5 plus a Head e g 3X Y5 plus accessories if ordered Do not unpack a PC card until you are ready to install it in the PC or the FieldPack unit Part Number Part Description Core Products PC BS5 Software Halfslot ISA Card 3 m long cable with D 15 connectors Will be a PCI card come Q2 2000 3XY5 Probe Style Head Silicon Detector with XY5 5um Slits 3
57. elects y profile only Reconfigures for a Pinhole scan Shift R Recall amp Process profiles Opens Auto Manual Gain dialog Page Up Access the previous profile Opens the Accumulation Page Down Access the next profile Averaging dialog Ctrl3 Toggles between profiles only and also showing the 2 D and 3 D views Ctrl E Opens the Program Head dialog rarely required Ctrl G Toggles between Geometric and Centroid based centroid definition Ctrl J Opens a Job file Ctrl M Reconfigures the screen for M measurements and toggles back to Normal Ctrl O Opens the Slit Orientation Dialog box Ctrl S Opens a dialog box for setting up the Auxiliary stage motion Ctrl T Screen dump to clipboard Image does not include the Button Bar Menu and Page Header above or the Help Notes and Task Bar below Ctrl V Opens the Average dialog box Ctrl X Opens the Slit assignment dialog box BeamScope P5 3 9 Quick Start Tutorial 3 2 HARDWARE QUICK START TUTORIAL 3 2 1 Setting Up If you have not already done so install the PC Card and software Sections 2 2 and 2 3 With the software off connect the head to the PC card using the cable provided Then start the software WARNING Never hot connect or disconnect the head while the software is powered up This can cause damage to the head and or the PC card electronics of the head Use a 0 Phillips head crosshead jeweller s screwdriver to unscrew the four screws which hold the slit a
58. ell the software to find the outer dimension of the beam and to ignore inner structure that takes the profile below the clip level For example a TEM 19 beam is double peaked and has a central intensity that falls close to zero If the TEM x x box were left unchecked the measured beam diameter would be only approximately half the actual diameter It will also fit the appropriate TEM profile to the beam Auto Search Normally this box is left checked telling the software to continually reassess the optimum scan range for the beam and to search for the beam if it moves out of range Uncheck the box if you wish to leave the scan range at that set up during Search Section 4 2 14 Auto Gauss Peak Normally this box is left checked See Section 4 2 13 for a more detailed explanation of the function The relative heights of the measured and Gaussian profiles is determined by equalizing the areas under the measured profile and the Gaussian profile and then setting the taller profile to 100 To normalize both profiles to 100 disable Auto Gauss Peak Filter Frequency Options This function is useful for Pulsed Lasers and Modulated Sources For CW lasers normally leave the slider at the extreme right in order to leave this function Off Pulsed lasers Note that the duty Filter Frequency Options cycle of any pulsed laser must be at gt Alternate least 10 with a repetition rate of Freq 1 995 Khz 10 duty min 4300 Hz preferably gt
59. ents u iii 1 12 2 INSTALLING BEAMSCOPE PS 2 cssssssssscssssssssssssssssnssssesesscsesnssssssssssssessesesessssoss 2 1 2 1 UNPACK THE BEAMSCOPE HARDWARE 22 PC CARD INSTALLATION 23 SOFTWARE INSTALLATION erre 2 3 1 Installation under Windows 95 or 98 2 3 2 Installation under Windows NT 24 FIELDPACK INSTALLATION ccscssesssssssesessecsesescescssenssecasenesecesecssenssecaeseenecsesecaeensaees 2 5 MOUNTING amp STARTING BEAMSCOPE 3 QUICK START TUTORIALS uu esssssssscsssssscsesssssssessesesesscsesnsessssssesssessesesessssess 3 1 3 1 SOFTWARE ONLY QUICK START TUTORIAL rin 3 1 1 Start the Software 3 1 2 Examine previously saved Data 3 1 3 Beam Centtoid c padana SA lena ale aan Leni no Ri 3 1 4 Beam Wander and Absolute position 3 1 5 Change the Beam Diameter Definition 3 1 6 Pass Fail Indication for QA amp Production Testing 3 1 7 Included Power and Distance Measurements on the Profile 3 7 3 1 8 Additional Profile Views c cssssssssssssssesesesscesesesssesesscsseseseseseseseseseseseaesescneaeaeaees 3 1 9 2 D and 3 D VieWwsssc ance SR TRE 3 1 10 Print the Results 3 1 11 Other Great Features 31 127 SHOE Chlszn ara aan 3 2 HARDWARE QUICK START TUTORIAL iii 3 2 1 SCIMAS UP ao ei apo 3 2 2 Hedd Setup and Options cuce alan lealzanai 3 2 3 Search for the Be tt s
60. er hot connect or disconnect the head while the software is powered up This can cause damage to the head and or the PC card electronics Starting Up Double click the BeamScope icon to start the software Wait a few seconds The head should make clicking noises as it references to an internal physical stop and the BeamScope main screen should appear If so go to Section 3 If you see Notice BeamScope board not detected this means that the software has not detected the presence of a PC card Carefully reinstall the hardware and the software If this fails contact DataRay Technical Support If you see Notice BeamScope head not detected this means that the software has detected the presence of a PC card but not the head If this occurs try the following Press Ctrl E and change the Maximum travel by mm Click OK If this succeeds try restarting the software If the attempt to Write to EEPROM failed contact DataRay Technical Support BeamScope P5 2 13 2 5 Installation BeamScope P5 CHAPTER THREE 3 QUICK START TUTORIALS Okay so you want to get started quickly without reading the manual but you don t want to damage the hardware or you just want to evaluate the software This short as possible chapter is for you Just follow the step by step instructions refer to other sections where noted and you will learn enough to measure beam profiles Later on you must find time to read Section 4 of the manual if y
61. es are the same If you are using slits other than the standard 5 um dual XY slits make sure that you enter the details under Number of Slits IMPORTANT Note that when a results file is saved the slit details are also saved and cannot be subsequently changed in the saved data Head Setup and Options BeamScope P5 3 11 Quick Start Tutorial 3 2 3 Search for the Beam It is CRITICALIY important that you properly understand this section Read it at least twice Span Ap 1060 Ap2 1798 Offset 11588 In Search mode the probe determines the location of the beam to be scanned 1 Click Aim to move the probe out and aim the beam at the center of the outer slit Then Press F4 to instruct the probe head to search for the beam TIP If necessary press F5 to perform repetitive searches then F2 to stop the search once successfully aligned as defined in 2 through 5 below 2 When a Search has been performed inspect the search display reproduced above and verify that the scan regions found by the search routine make sense The X slit Ap1 and Y slit Ap2 scan regions are indicated as dark gray regions marked 1 and 2 The width of this plot is the 34 mm long physical scan of the probe With dual slits after a search is preformed there should always be two distinctly separated peaks displayed That is there should always be a horizontal distance between the right hand edge of the 1 region and the left hand edge
62. ference starting point this reference could be a reference laser beam or the initial position of the beam under investigation It is also possible to enter zero position numbers in the Wander Setup Information dialog box See the next page 4 2 6 Beam Wander Button A position vector is traced from the center of the display to the dashed crosshair which indicates the beam center The dashed ellipse indicates the 13 5 intensity profile of the beam If Auto Scale On box is checked see below the arrow zoom is disabled then clicking on the arrows either side of Zoom changes the displayed area At any point in time the user can press the Zero button to set the most recent beam position as calculated by the BeamScope software as zero This current reference point will be used in subsequent Centroid and Beam Wander results The Beam Wander button area contains five distinct buttons Zero Absolute Zoom In Zoom Out 4 10 BeamScope P5 BeamScope Functions and a general button in the Beam Wander area Click on this area to open the Wander Setup Information dialog box and set parameters The screen shown indicates typical settings including Auto Scale On Values for a zero Wander Setup Information FS or an absolute reference position may be entered in Zero Point X LENIE Y 18647 9 _ Lock the Zero Point Absolute X Y 0 0 Coos zern amp Absolute bo er boxes Absolute _ Reverse X Y _ Negate X _ Negate
63. five below the diffraction limit it may be shown Ref 3 that f number gt 137 4 10 Where fmm is the focal length of the lens Aum is the laser wavelength f number is defined as f divided by the 1 e diameter of the beam at the lens For a 25 mm diameter 75 mm focal length plano convex lens this leads to Anm f Max Beamwidth at Lens 400 gt f 12 7 2 0 mm 633 gt f 11 3 2 2 mm 830 gt 10 6 24 mm 1064 gt f 9 9 2 5 mm Due to the 0 25 power dependence in equation 10 even a wider tolerance such as allowing the aberration contributions to be equal only decreases the f number to gt f 7 6 at 633 nm for a maximum beamwidth of 3 3 mm Ref 2 conservatively recommends gt f 20 in all circumstances It is therefore important to perform such a calculation for the lens employed and if B necessar l ith ei i i App y use a lens with either with lower aberrations or a longer focal length Typically the choice to reduce spherical aberration would be either an achromat which 3 3 normally has significantly reduced spherical aberration or a laser focusing singlet A 3 4 longer focal length plano convex singlet may be a solution But only if the Rayleigh range can be kept low enough for the scan range if a scanning M stage is employed See e g DataRay s BeamScope P5 with its M Accessory scan stage BeamScope P5 A 9 Appendices 4 Beamwidth Definition 4 1 Gaussian Beams True Gaussian beams have no
64. g What do I do next BeamScope P5 2 9 2 4 Installation Answer a Check that the cables are properly connected and the power was on Step 5 If so then the most probable cause of the Notice is that the parallel port is not correctly configured for bi directional communication You must change the parallel port mode in your PC s System BIOS setup The System BIOS is accessed by pressing a particular key while the computer is rebooting This is commonly the F1 F2 F10 or Delete key or whatever your PC manufacturer decided on To find out ideally consult the Owner s Manual Documentation that came with your PC no we are not joking some people keep it or contact the PC manufacturer http Awww hp com cposupport multifunction support_doc bpu50187 html has a section on ECP and Bi Directional Interfaces addressing how various manufacturers access Bios to set the parallel port Alternatively restart you computer and scan the white on black text screen that appears for a message naming the particular key to be pressed Press lt __ gt to enter SETUP or some similar message Quick press the key If you are too late restart the computer and this time press the key immediately after the beep as soon as the black and white screen appears If absolutely necessary and completely at your own risk experiment with the F__ keys Once in the BIOS program normally a gray or blue DOS screen find the Parallel Port Mode typ
65. ge Auto Range 4 22 see also Search Rayleigh Range A 5 Representatives A 13 Returns A 13 Save 4 3 Saved Data examining 3 3 Scanning Stage Chapter 6 Search 3 12 4 17 Auto Search 4 23 Setting up 3 10 4 22 Setup 4 5 4 22 Set Up and Options 3 11 4 22 Short Cuts keys 3 15 Slit Mode 4 26 Slit Size entering 4 22 A 18 Size recommended 4 27 Slits Changing 3 10 Orientation 4 24 Setup screen 3 11 4 22 Software Installation 2 4 Specifications BeamScope P 5 1 5 FieldPack 1 10 M Accessory 1 10 Stage Setup 5 1 Start F1 3 13 Status Button 4 12 Stop F2 3 13 Support Technical A 13 T Technical Support A 13 TEMxx 4 23 Test see Pass Fail Tilt profiles 4 13 Tracking centroid 4 23 Tutorials BeamScope software 3 2 BeamScope hardware 3 10 M Squared software 5 2 M Squared hardware 5 4 U V View profiles 3 7 4 13 4 15 2D 3D 4 13 W Wander 3 5 4 10 Wavelength 5 4 Width 3 5 4 14 Windows 95 98 installation 2 4 Windows NT installation 2 6 BeamScope P5 X X profiles aperture see Profiles topics X Slit Factor 4 22 Y Y profiles aperture see Profiles topics Y Slit Factor 4 22 Z Zero centroid 4 10 Zoom beam wander 4 10 Numeric 2D 3D profile views 3 7 4 13 4 15 2D Scanning Stage Chapter 6 Specifications 1 10 BeamScope P5 Appendices A 19 xaz Appendices A 20 BeamScope P5
66. ging Dialog 4 20 Average Dialog 4 20 Logged data 3 13 4 21 Profile see Accumulation Averaging Dialog 4 20 Rolling of n values 3 6 4 4 Running Average 4 4 Auto Gauss Peak 4 15 4 23 Auto Gain 4 18 Auto Manual Gain Dialog 4 18 Auto Range 4 22 Auto Rotate 3D 4 14 Auto Search 4 17 Auto scale beam wander 4 10 Auto TEMxx 4 23 Axis match to apertures 4 24 B Beam Centroid 3 4 4 10 Diameter 3 5 4 15 Irradiance A 10 Profiles 4 15 Structures A 13 Distance on a profile 3 7 4 16 Distributors A 13 Divergence angle 4 19 BeamScope P5 E EEPROM program 4 26 Ellipticity 4 10 EXCEL save then export data to 4 3 F F Function key short cuts 3 14 Feature Included Power amp Distance 3 7 4 16 FieldPack FAQ 2 9 Installation 2 8 Schematic 1 11 Specifications 1 10 Elle 4 3 Filter Frequency options 4 23 Functional description BScope 1 3 Functions 4 1 Button Bar 4 6 Button Colors Setup 4 9 Pull down menus 4 2 Pass Fail QA Testing 4 8 Request Form A 1 G Gain Auto Gain 4 18 Auto Manual Gain Dialog 4 18 Gain and Power button 4 11 Manual Gain 4 18 Gaussian Beams A 10 Gaussian Fit Beams A 10 Button 4 12 Algorithm 4 29 Auto Gauss Peak 4 15 4 23 Grid vertical 4 16 H Head Changing slits 3 10 Mounting 2 13 Program Head EEPROM 4 26 Setup and Options 4 22 Speed 4 25 Help 4 6 Help Hints 4 9 I Included Power 3 7 4 16 Installation 2
67. h the ISO 11146 standard 5 2 M HARDWARE SETUP 1 2 3 4 5 6 5 4 Set up the M Accessory and the BeamScope Head on the M plate if provided as shown on the next page or use the hardware provided available to achieve a similar configuration N B You cannot substitute an Ethernet cable for the high current M cable which has similar connectors The M2B stage is assumed see page 5 1 If you are using the BeamScope Rotatable Head then you must use an optical breadboard or optical table plus appropriate mounting hardware to position the Head with respect to the M Accessory The lens should be nearest to the BeamScope s slit when the stage is in the Home position The focussed beamwaist should be 15 to 25 mm 5 to 15 for the M2A stage behind the BeamScope probe head To verify alignment the laser should reflect off the center of the lens amp back near to but not back into the source With the lens out press the Aim button and set the laser 7 mm out form the head Then screw back in the lens and check that the laser hits the center of the lens If the beam is substantially elliptical align the beam major axis with the X or Y slit The laser should be at least one Raleigh distance from the lens If the estimated zp is less than 250 mm then use a minimum source to lens separation of 250 mm 10 inches Estimate the Rayleigh range of the source from the estimated or specification source waist diameter and
68. hardware is installed The latest version of the BeamScope P5 software is available from your representative or from DataRay s web site at www dataray com Visit www dataray com in order to verify that you have the most recent software revision 5 3G at the time of writing If you do install the BeamScope software in the Windows standard manner instructed on the diskettes If you do not have the latest version you must upgrade or we cannot provide support Either If you have already loaded the BeamScope software download the Bsexe zip file to a temporary file and extract into the Bscope5 directory When the Confirm file Overwrite warning appears select Yes to All Or To start again from scratch download the BSDisk1 zip and BSDisk2 zip files Extract both of them to a temporary folder e g c DRaydisk or to diskettes Open Windows Explorer and double click Setup exe to install the program WARNING Never hot connect or disconnect the head while the software is powered up This can cause damage to the head and or the PC card electronics 2 3 1 Installation under Windows 95 or 98 These instructions assume that you are running Windows 95 or 98 However you can use it with Windows 3 1x with some allowances on your part This tutorial also assumes that you are reasonably familiar with Windows We do not support Windows Me 1 The BeamScope PS software is installed from within Windows If your computer is not running Win
69. he desktop Then rename it as above 2 12 BeamScope P5 Installation 2 5 MOUNTING amp STARTING BEAMSCOPE These instructions apply to both the standard Probe style head and to the Rotatable Head The Rotatable Head does not have a rotating slit or drum It takes the standard linear probe mechanism and mounts it on a circular bearing with scale to allow simple manual rotation 1 Mount the BeamScope head in a rigid manner using the 44 20 and M6 tapped blind holes and appropriate mounting hardware such that the probe will intercept the laser beam and will move in a plane perpendicular to the beam axis See the Aim and Search functions described in Sections 4 1 2 and 4 2 14 Q For beams below lt 50 um in order to minimize vibration it is highly recommended that you mount the BeamScope Head vertically on a single post with the probe pointing down Q If the beam profile is elliptical and you are using dual X Y slits set the head such that the slit axes correspond to the beam axes A rigid mount is required because BeamScope employs a linear motion probe with what is essentially a square wave oscillating velocity profile linear motion is required to meet the ISO 1146 beam profiling standard Therefore if you simply attach BeamScope to the end of a long rod the probe s alternating linear motion may lead to oscillatory motion of a few microns of the head rod combination and you may not achieve the stability you seek WARNING Nev
70. he width of this plot is the 34 mm long physical scan of the probe With dual slits after a search is preformed there should always be two distinctly separated peaks displayed That is there should always be a horizontal distance between the right hand edge of the 1 region and the left hand edge of the 2 region The scan regions should never overlap along the horizontal axis 3 It is possible for the Auto Search function to mistakenly place the X and Y scan areas at the same location which may or may not be desirable Sometimes the software will allocate Ap3 and Ap4 The user must overwrite this as follows e Click and drag to move a scan region manually to the desired scan region e Define a new scan region by placing the cursor outside the gray region and clicking and dragging a new region with the mouse When the mouse button is released a menu will appear asking to Set Ap2 which aperture the defined region should be allocated In the current release only allocate Ap1 or Ap2 to scan regions Set p3 Warning To ensure valid results the entire profile must be within the scanned area set Ap4 4 Double click on the lower part of the search area to cycle the size of the search display from normal to large to minimum and back to normal BeamScope P5 4 17 4 2 BeamScope Functions 4 3 PULL DOWN MENUS ADDITIONAL DETAILS 4 3 1 Options Menu Auto Manual Gain Dialog ALT A Gain is the amount of ERE simplifiva
71. how can you know zg and work within the z zp regions indicated by the discussions above In practice O An approximate value of M may be known and 2 can then be estimated before setting up and starting the measurements O zgcan be calculated from the M measurements After the first run the set up can be assessed in order to verify that the z zg region is in accord with condition 9 3 3 Inaccessible Beam Waists If no accessible beam waist exists then an ancillary lens must be used to form the waist This is normally the case when the laser itself is being measured since the beam waist is in the vicin ity of the output mirror Diverging beam from inaccessible waist Lens New waist The ancillary lens used to form the waist should be in the far field of the laser preferably gt Zp i e Zp for the laser source from the limiting aperture or laser waist Away from diffractive overlay from the mode selecting aperture of the laser Ref 2 For a typical HeNe 2W 0 8 mm divergence 1 mrad zr 2Wy 0 0 8 m A 8 BeamScope P5 Appendices 3 4 Correct Waist formation using a Lens In order not to increase the M of the original beam this lens must be used within its aberration free diffraction limited region of operation For a plano convex singlet typically employed in these applications spherical aberration is the dominant on axis aberration In order to keep this contribution well below a factor of
72. ically found under Advanced in a submenu called Peripheral Configuration or something similar All PC manufacturers in theory follow the IEEE 1294 Standard for the Parallel Port but in practice there are differences Choose Bi Directional mode If this does not work next try ECP then try EPP i e select from the following modes listed in order of preference a Bi Directional b ECP c EPP The BeamScope FieldPack will NOT work in Standard mode Save the BIOS changes normally by pressing F10 and re boot the computer Retry the BeamScope software Step 6 The program should now work b If you have tried a without success then in order to restore the BeamScope defaults in case they somehow got corrupted proceed as follows From the Desktop single click the BeamScope icon hold down the Shift key and then press Enter Keep holding down the Shift key until either the BeamScope main screen appears indicating success or an error message notice appears Note any error message notice Please carefully record the exact words that appear you can use Alt Print Screen to put the messaage window to the clipboard and then save it under Paint as a bmp file and send the file optionally zipped to DataRay Technical Support see website 2 10 BeamScope P5 Installation Q2 What addresses does FieldPack software look for when trying detect and configure for the parallel port Answer The following four Preferred Sometimes
73. indwept in the horizontal direction Why Your stage is probably stalling due to the load and or load orientation This was an issue with some early versions of the 2DSS stage and board See the bottom of page 4 1 for a temporary solution Contact DataRay Technical support for a permanent solution Q3 There is a vertical oscillation in the beam image which I do not believe is real Why This is residual side to side movement in the stage at the screw pitch of 700 um It will be corrected in the M2C 2DSSC stage due early summer 2001 BeamScope P5 6 3 6 2 6 3 2D Scanning Stage 2D SS Stage BeamScope P5 head Schematic Setup 2DSS AAP Adaptor Plate e 2DSS Stage 6 4 BeamScope P5 APPENDICES APPENDIX A BEAMSCOPE P5 FUNCTION REQUEST FORM APPENDIX B M SQUARED AND ITS MEASUREMENT cssssssssssssssssssssssseseseees 1 WHY CARE ABOUT M SQUARED ccccccsscsscssessessecsecsecssesessessessessesesseesessessenscascaecsaesaesaenees 3 2 M DEFINITION amp FORMULATIONS 2 1 A SYMMETRIC amp A STIGMATIC BEAMS 22 THE ISO 11146 STANDARD Ra 3 M MEASUREMENT 3 1 Accurately Measuring the WaiSt iii 3 2 Accurately Measuring Divergence and or 2w z versus z 3 3 Inaccessible Beam WaiSts iii 8 3 4 Correct Waist formation using a Lens 4 BEAMWIDTH DEFINITION iii 4 l Gaussian Besos alia alla lada 4 2 BeamIrradiance
74. ion Extended Probe Head i the probe sticks out an 35 mm additional 30 mm It still travel only travels 35 mm i IS Probe face to slit plane 0 75 mm Head face to slit plane 2 75 mm Dual Slits 45 Single Slit 0 7 mm long 7 mm long 10 mm center to center separation BeamScope Head shown actual size BeamScope P5 BeamScope P5 1 9 Introduction M Accessory 2 D Stage Specifications Lens Detached for 2 D Stage operation Stage Travel Step Size Dimensions M Accessory 2 D Stage M Accessory Plate M Base Plate Weight M Accessory Coated Achromat 1 4 550 nm Focal Length 85 mm 1 5 mm or 2 Clear Aperture 17 5 mm M2B amp 2DSS 45 mm 3 5 um M2C amp 2DSSC 45 mm 2 5 um Across axis width x Height x Along axis depth 71x87 x 140mm 2 8 x 3 5 x 5 6 inches 50 4 x 6 3 x 127 mm 2 0 x 0 25 x 5 0 inches 152 x 25 4 x 305 mm 6 0 x 1 0 x 12 0 inches 680 gm 1 5 Ib FieldPack Specifications Dimensions excluding connectors Weight Length x Width x Height 257 x 195 x 25 mm 10 1 x 7 7 x 1 0 inches 1090 gm 2 4 lb BeamScope P5 200 mm 8 0 Schematic FieldPack Function BeamScope P5 FieldPack connects BeamScope M option to a Notebook PC Introduction 1 5 Introduction 1 5 1 Computer Requirements m m BeamScope P5 is not available in a Mac compatible software version 66 MHz 486 minimum 100 MHz Pentium or faster pr
75. ions consider setting the Scan Width and Height in order to maximize resolution on your beam Click on Stage Setup to open the box or enter CTRL S select your stage and click OK Part default 1 M2A default 2 M2B 2DSS default 3 M2C 2DSSC BeamScope P5 Two D Scan press to setup pLi II iTi i N K hao ssonm gt 6 1 SetReference Reference Home Stage _ su con a sove sen Help Scan Range Step Size 20 mm 44 3 um 45 mm 3 5 um 45 mm 2 5 um 6 1 2D Scanning Stage Max stage travel mm Stage step size um default 1 default 2 New Scan Width um Scan Heigth fos um Yi Auto Width recommended Height Width cable drive lead srew lead srew 7 Normal Bitmap 512 X 512 Slower Normal Fast Faster Stage Setup Mic You may choose the scanning speed to be Faster or Slower but Normal works for most scenarios If you have any stalling problem click on the Slower button Click OK to leave Stage Setup Click OK to leave TwoD Scan Setup Click the Home Stage button Once the stage stalls on the internal physical endstop at the motor end of the stage The stage will make a buzzing noise as it stalls Press F2 to stop the motor This sets the zero position of the stage If it stops before reaching the end press the Home Stage button again until the stage does reach the end If for any reason the stage homes to the end opposite the motor go to the Stage Setup dialog box right and clic
76. ip Level Entry dialog box allowing the Width Calculation Method user to set a desired clip level or select the use of the Variance beam diameter Also known as Second moment or 4 width see page A 11 Note that two distinct clip levels and or methods can be set concurrently in the upper and lower levels gt Variance second moment If used clip level is ignored gt Knife Edge FWHM gt 13 5 1 e2 4 50 FWHM gt 86 5 Clip 50 00 The outer set of buttons displays the calculated beam diameters in microns um or millimeters mm as selected in the Pass Fail Parameter Setup dialog box The beam diameters on the left corresponds to aperture 1 profiles normally designated X and the right to aperture 2 normally designated Y A bracketed number e g 10 following the width reading indicates that it is being averaged See Page 4 4 4 14 BeamScope P5 BeamScope Functions 4 2 13 Beam Profiles Area This is the area used to display the actual profiles X Apl 45 deg Y Ap2 45 deg ttt EAT TE LUA LIO Le BROS IE ARE Br HRT mimi aE 44 8 9 um div 44 44 8 7 um div For clarity the above image is shown with display parameters set to their default settings The vertical axis gridlines are displayed in linear mode at 10 intervals The X axis is labeled in microns e The measured profile is shown in black The fitted Gaussian profile i
77. isabled TCP IP Service Started Automatic tga Disabled Stop tmy1 Disabled Disabled Startup Si sstem ideare HW Profiles Disabled od Disabled 7 Help Select totalio Note that totalio should be Started and is labeled System IT MUST BE THIS WAY If it is not labeled System press the Startup button and change it to the System option It may or may not complain about something but if it does just ignore it If Started is not there press the Start button Finally Close the dialog box and restart BeamScope BeamScope P5 Installation 9 That s it BeamScope should run now next time and every time after that If not contact technical support at support dataray com Congratulations You have successfully completed BeamScope Installation Go to Section 2 5 WARNING Never hot connect or disconnect the head while the software is powered 2 3 up This can cause damage to the head and or the PC card electronics BeamScope P5 2 7 Installation 2 4 FIELDPACK INSTALLATION FieldPack works with most standard Desktop or Notebook PC s with a parallel port input running Windows 95 98 NT Combining FieldPack with a Notebook PC creates a compact portable beam profiler Due to the non rigorous nature of the implementation of the parallel port standard we cannot guarantee that FieldPack will work with just any PC This is particularly true of budget products and some Compaq models with non standard Bios We have ha
78. k on the Reverse stage direction button 6 2 OPERATION 1 Click in the center 1 A E AN ARA LL Sal mm the graduated scan N 22 501 45 0mm gt stage position indicator The stage will move to the center of its range 2 Click Aim on the main button bar to set the pinhole in the middle of its travel 3 Adjust the source or the stage support such that the source is approximately centered on the pinhole You may also move the stage To adjust the stage position you may use the Step arrows at either end of the graduated scan stage position indicator If you do move the stage in this manner you reduce the maximum scan range by twice the off center adjustment that you make Click the Search button on the button bar and verify that the search display shows a signal If it does click the Set Reference button 4 Click on Start Scan F9 The following occurs 6 2 BeamScope P5 Appendices e The software instructs the head to measure the line profile 13 5 clip level diameter of the source at the reference position The program will automatically set the gain and lock it In order to allow for any hotspots the gain is set to 25 of the peak value detected during the search The software also turns off all Auto functions in Scan Head Setup as opposed to Stage Setup during the scan e Using the scanning stage it then moves the head to the start of the scan It scans a 2D region centered about the reference positio
79. n The width of the region is twice the diameter of the beam detected by the scan The scan will build up on the screen from left to right The size of the scan is always 512 x 512 steps The minimum step on the 2DSS scanning stage is 3 5 um therefore the minimum scanned area is 1 792 mm long 5 At the end of the scan click on Save to save the image as a Bitmap The step sizes are stored in the bitmap so that when it is imported into WinCam software the size information is not lost 6 If you find the scanned area to be inadequate for example your beam had the minor axis set parallel to the probe scan axis then you will need to over ride the Auto Width Item 3 above by unclicking Auto Width and entering a Scan Width in microns 7 Open the saved file under WinCam and analyze the image At this point in time WinCam software and a WinCam user manual are supplied with the 2DSS stage Both are available from DataRay or may be downloaded from www dataray com 6 3 FREQUENTLY ASKED QUESTIONS Q1 My source appears crescent shaped and I don t believe it What s going on Due to an assembly error a few pinhole assemblies made in late 98 early 99 have shown leakage round the edge of the pinhole disk This tends to show up as a crescent of a circle with a diameter of 10 mm You may cure the leakage with black paint epoxy nail polish or return it to DataRay for repair replacement Q2 My source image appears compressed skewed w
80. n noise due to inadequate dynamic range in the sensor or the ADC analog to digital converter leads to errors in the second moment In general it leads to an over estimation of the second moment width c Ifthe I x y z intensity profile has wings which fall at a rate slower than 1 x or tly then the double integral actually increases as X and y increase For reasons b and c most commercial second moment beam diameter software first automatically determines and subtracts the background and then truncates I x y z to the BeamScope P5 A 11 App B 4 3 Appendices zeroed background level at a predetermined distance from the 1 e diameter Some software allows the user to override this distance 5 Acknowledgements In parts this Application Note draws on Reference 2 and we have used the same notation wherever possible 6 References 1 ISO 11146 Optics and optical instruments Lasers and laser related equipment Test methods for Beam widths divergence angle and beam propagation factor Published by the International Organization for Standardization 2 T F Johnston Jr Beam propagation M measurement made as easy as it gets the four cuts method Applied Optics Vol 37 No 21 20 July 1998 pp 4840 4850 3 Anonymous Fundamental Optics Lens Selection Example 4 Melles Griot 1997 98 Catalog Appendices Equation 4 assumes equal contributions from diffraction and spherical aberration This appli
81. nt processing all values below 2 of peak and all points at greater than 2Wp from Xp are ignored treated as zero In the formulae which follow Lx implies the sum from 2Wp to 2Wp BeamScope P5 4 29 4 6 BeamScope Functions 4 5 6 7 8 9 10 11 12 The centroid to the profile first moment is calculated Xe Lx X Ip X Lx Ip x The area under the curve is calculated Ap Lx Ip X The variance second moment is calculated ox Lx x x0 lp x lp X The variance based beam diameter is calculated 2wy 40x A Gaussian profile lg X is defined with 13 5 diameter 2W G 2W the calculated second moment diameter and the same centroid Xe The peak height of this Gaussian is adjusted to give it an area equal to Ap On a point by point basis this reference Gaussian profile le X is compared with the beam profile Ip x Positive and negative errors are summed separately Keeping the area Ap constant the Gaussian peak height and width are iteratively adjusted until the sum of the positive and negative differences is zero to give a revised Gaussian width 2W g and a height given by Ap 2W al The Gaussian Fit displayed as a factor or a percentage is calculated as the absolute sum of the profile differences divided by the total area Gaussian Fit 1 Abs Ip x le x dx Ap The Gaussian profile is displayed in red on the profile display The relative heights of the measured and G
82. om Aperture 1 X is the keyboard shortcut Sets the BeamScope PS to display profile Y from Aperture 2 Y is the keyboard shortcut XAY Sets the BeamScope P5 to display scans X and Y from Apertures 1 and 2 B for Both is the keyboard shortcut EK e BR 4 6 BeamScope P5 BeamScope Functions Causes the BeamScope P5 to start scanning F1 is the keyboard shortcut Causes the BeamScope P5 to stop scanning to E F2 is the keyboard shortcut Causes the BeamScope P5 to perform a single scan F3 is the keyboard shortcut Causes the BeamScope P5 to perform a search scan operation Fa F4 is the keyboard shortcut HEOR Sets the BeamScope probe at the X profile centroid You may aim your beam 4 1 at this lit to set up the approximate alignment F7 is the keyboard shortcut Fully extends the BeamScope probe head to allow simple access to change the aperture plate E When clicked steps the data to the previous profile in the data buffer Page Down is the keyboard shortcut When clicked steps the data to the next profile in the data buffer Page Up is the keyboard shortcut If activated opens profile selection dialog box If activated reverts to active data If activated reverts to recalled data Prints the current screen without user supplied notes DEEA mpg EE Prints the current screen with user supplied notes e Screen dump to clipboard Image does not include the Button Bar Menu and
83. ore any measurement within 1 7 of a Rayleigh range of the z 0 beamwaist position can in principle measure 2Wo to within 1 A small table can be constructed 2W Accuracy Sought Allowable z zz error t1 14 0 0 App 2 20 B t5 32 3 1 10 45 3 2 Accurately Measuring Divergence and or 2w z versus z Divergence may be measured directly at large values of z zR Referring to figure 1 at large z the diagonals defining are asymptotic to the hyperbolic curve of 2W z versus z and could be calculated from 2W z as 2 arctan W z z 8 2W z z for small The error in this assumption may be calculated from equations 4 and 8 to be BeamScope P5 A 7 Appendices Error from 2W z Error z zr value lt 1 25 7 lt 2 24 4 lt 5 23 0 lt 10 22 2 Since some of these z zg values may be inconveniently large is not normally measured directly Instead M is calculated by fitting the measurements of 2W z versus z to the hyperbolic curve of equation 6 Ref 2 shows that for maximum sensitivity to the fractional change versus z in the shape of the hyperbolic curve it is preferable to work within the region 0 5 lt z zg lt 2 0 9 Working at values of Z ZR lt 0 5 compromises the accuracy of the measurements Working at values of z zr gt 2 0 is not as big a problem but leads to lower accuracy as the ratio increases But unless M is already known
84. ou are become a BeamScope power user but for now Q Unfamiliar with BeamScope or just evaluating the software Read Section 3 1 first Q Acquainted with the software but never used the hardware Go to Section 3 2 3 1 SOFTWARE ONLY QUICK START TUTORIAL cri 3 1 1 Start the Software 3 1 2 Examine previously saved Data 3 1 3 Beam Centroid iiee 3 1 4 Beam Wander and Absolute position 3 1 5 Change the Beam Diameter Definition iii 3 5 3 1 6 Pass Fail Indication for QA amp Production Testing uuriie 3 6 3 1 7 Included Power and Distance Measurements on the Profile 3 7 3 1 8 Additional Profile Views c scsssssssssssssssssssesssssesescsssssenssssssesesessseseseaeaeseacaseesees 3 7 3 1 9 22Dahd 3 D Views Enc EL ie 3 7 BLO PrinttheResultsa Gacpala luo ASL a CARELLA STO IG 3 8 3 1 1 Other Great Features ss aan 3 8 Fed 12 SHOP CUIS sai cose ela Ele alan ini 3 2 HARDWARE QUICK START TUTORIAL 3 2 1 Setting Up ie 3 2 2 Head Setup Gnd Options calano lena alano 3 2 3 Search forthe Beata ir 3 2 4 Practice with the SOftWAC cccceccsescscecesecssecesesssecesesecesececesesesesteeeeetateeeeers 3 13 3 2 5 Log the Data 3 2 6 Short Cuts BeamScope P5 3 1 Quick Start Tutorial 3 1 SOFTWARE ONLY QUICK START TUTORIAL This section will teach you the basics It does not try to cover everything Yes you will eventually have to read Se
85. paration 5 mm for 7mm long slits V4 20 amp M6 threaded mounting holes 540 gm 1 2 Ib 00 gti 10 to 35 C 5 to 45 C 66 MHz PC 486 100 MHz or better Pentium preferred running Windows 3 1x 95 98 or NT 4 MB RAM ISA Slot PCI card coming Q4 2000 10 MB Hard Drive space SVGA 600 x 800 monitor BeamScope P5 Introduction Notes A The 2 D and 3 D profiles are reconstructed from the X Y scan making the assumption that the measured X beam profile is the same for all values of Y and that the measured Y beam profile is the same for all values of X 1 5 O In Slit or Pinhole mode the slit pinhole width should be lt 1 3 of the diameter of the beam under measurement For X Y slit pairs inclined at 45 the ratio is approximately 1 5 E g for any beam below 20 um diameter use the 2 5 um slits wherever possible O In Knife Edge mode the slit width should be gt 3x the beam diameter For X Y slit pairs inclined at 45 the ratio is gt 4 3 times the beam diameter The graph allows you to simply determine the approximate maximum CW optical power that BeamScope can measure without additional 1000 SSS attenuation The limit is a detector mw current limit Approximate saturation beam power 100 um beam diameter 5 um slit The graph shows the approximate 400 saturation beam power in mW versus wavelength for a 100 um diameter beam 1 e amp a5 um slit
86. ple shielded BS CAB cable 4 5 m 15 ft long Pinhole 5 um diameter Pinhole 10 um diameter Pinhole 25 um diameter Single Slit 2 5 um wide x 7 mm long Single Slit 5 um wide x 7 mm long Single Slit 10 um wide x 7 mm long Single Slit 25 um wide x 7 mm long X Y Slit 2 5 um wide x 7 mm long 45 X Y Slit X Y Slit 10 um wide x 7 mm long 45 X Y Slit 25 um wide x 7 mm long 45 5 um wide x 7 mm long 45 X Y Slit 100 um wide x 7 mm long 45 XY center to center separation is 10 mm Planarity 40 um Dual planar X Y Slit 2 5 um wide x 3mm long planarity set to 4 um Dual planar X Y Slit 5 um wide x 4mm long planarity set to 4 um BeamScope P5 Installation 2 2 PC CARD INSTALLATION The BeamScope P5 controller card has been designed to be easy to use and easy to install There are no switches or jumpers to set Follow the simple steps below It is recommended that you work at a static safe work station and wear a wrist strap 1 2 3 4 5 6 7 8 9 10 11 Turn off the power to your computer amp disconnect all power cords Remove the cover Select an expansion slot for the BeamScope PS It is preferable that the card have a maximum amount of breathing room for heat dissipation Remove the rear slot cover bracket if present Save the screw for future use If you are not working at a static safe work station amp wearing a wrist strap to reduce the risk of st
87. r than the slit dimension change to Knife Edge mode Section 4 4 and reinterpret the data 7 In Section 4 3 3 you will learn how to turn the Auto Range and Auto Search functions on and off under Setup in order to keep the scans over a preset region 3 2 4 Practice with the Software If you have not already done so go through sections 3 1 3 to 3 1 10 above and refer to Chapter 4 for any areas which you wish to pursue in more detail 3 2 5 Log the Data It is frequently desirable to be able to investigate L fil dri x drift in the measured parameters Enter Alt L L to open the Log profiles to drive dialog box Click on CAPTURE ENABLE IS OFF or New PE to open a Save Asdialog box which allows you Captured profiles 0 specify a filename and location Click OK File Size 0 The button will change to CAPTURE ENABLE ae IS ON Click F1 to start the scans The data will i be logged to file Click F2 to stop the scans CLEAR NEW CLOSE Click on Analyze profiles to open a BeamScope Data Analysiswindow Click on File Load to Opena logged data file Examine the logged profiles and statistical data An example is given below Note the Save Load Edit and Print Analytically the Std Error in the Mean is Sum Value Mean n n 1 Where n is the number of values considered in the calculation BeamScope P5 3 13 3 2 Quick Start Tutorial E Ellspsed time 0 H 0 M 7 5 Width cum E 3
88. red Y profile is the same for all values of X since this is the only reasonable reconstruction of the information contained in two orthogonal scans If only X or Y has been scanned the software assumes the X amp Y profiles to be the same and generates a pseudo reconstruction with 2D symmetry To set the view angle and tilt press and hold down the left button of the mouse while the cursor is on the 3D area and move the cursor Left right cursor motion rotates the 3D display about a vertical intensity axis Up down motion changes the tilt angle BeamScope P5 4 13 BeamScope Functions Right click on the 3D area to open a floating menu that Background color allows various display options to be selected Since the 3D Auto Rotate option consumes PC processor power it is recommended that this display option be turned off w Vertical Grid when taking data v Show clip level Double clicking on the 3D area to alternately swap the 3D view with the larger area normally occupied by the 1D profiles Use thick pens slower v Linear mode Log10 30dB Logi0 40dB Logi0 50dB Plot History 4 2 12 Beam Widths Buttons This set of seven button areas controls the display of the beam diameters and their corresponding clip levels Right click on any of the buttons to set custom display colors Beam Widths 13 5 Clip 0 167 mm 0 164 mm 13 5 Clip 0 167 mm The two center Clip Level buttons open the MAUI ALS EI Cl
89. requency Options Divergence Angle Z distance MODE Pointto Point Alternate Off 10 duty ee Z Distance 6 0000 mm Degrees Radians NA Q Number of Slits Click in the appropriate diamond to choose the appropriate slit or pinhole type Enter the Slit Size in microns The Recalled box shows the slit dimension for the most recently recalled data file Q X Slit Factor and Y Slit Factor A cosine correction factor for misaligned slits an occasional issue on older P3 models Normally leave these factors at 1 000 Q Auto Range Normally leave this box checked and the slider set at the default position of 1 3 Slide the slider to the right to increase the scan range over that 4 22 BeamScope P5 BeamScope Functions determined by the software to be adequate Unchecking the box reverts to a user set scan range see section 4 2 14 Tracking Leave this box checked if you want the software to track the centroid and to continuously reset the scan range about the centroid Centroid Clip Level Leave this at 13 5 unless you have a good reason to select otherwise A good reason might be significant structure in the wings that went above the 13 5 level To ignore this structure set the Clip Level appropriately higher Auto TEM x x Normally this box is unchecked However if the laser is not close to a Gaussian TEM 9 but has dips within the profile that go below the clip level set under Beam Widths check this box to t
90. ric amp Astigmatic Beams So far this note has assumed circularly symmetric beams the shapes are identical in X and Y Real beams are frequently asymmetric and astigmatic That is a The beams may be purely asymmetric having the same waist positions Zx Zy but different waist diameters 2Wox 2Woy or b The beams may be purely astigmatic having different waist positions x Zoy but with 2Wox 2Woy or c The beams may be asymmetric and astigmatic having different waist positions ax zy and different widths 2Wox 2Woy or d The beams may exhibit neither astigmatism nor asymmetry at the beamwaist but may have asymmetric divergence Opx Oy Condition a b c or d or any combination thereof leads to My My Any attempt to measure M must realistically assume c until the measurements prove otherwise Although the rest of this note assumes circular symmetry and a single dimension the reader should always bear in mind that both X and Y measurements should be taken in order to characterize the beam accurately and adequately 2 2 The ISO 11146 Standard The ISO 11146 standard See Section 4 of this Application Note and Ref 1 discusses both beamwidth and M measurement in more detail Importantly it defines that Q Second Moment rather than Gaussian equivalent diameter must be used when establishing 2W z versus z See section 3 5 3 for the second moment formulation The second moment diameter is specified because onl
91. rrent Job file parameters Print Prints the current BeamScope P5 screen with the date Print with Notes Prints the current BeamScope P5 screen with the date and user supplied notes added Print Setup Opens the printers setup dialog box Exit ALT F4 Terminates the BeamScope P5 program BeamScope P5 4 3 BeamScope Functions Options Log Setup Palette Help Auto Manual Gain Dialog Alt A Auto Manus Gein Dialog ALT A Opens the Auto Show 2D 3D views CRTL 3 Manual Gain Dialog 2 CTRL M box Most users will TwoD scan 4LT F9 never need to use this Angular Displacement ALT F7 function See section 4 3 1 for additional Accumulation Averaging Dialog ALT N detail Average Dialog CRT Average Widths gt Show 2D _3D views CTRL 3 Opens 2D and 3D representations of the current profile s CTRL 3 toggles these 2D and 3D displays on and off M22 CTRL M Reconfigures the main window into the M window See Section 5 TwoD scan ALT F9 Reconfigures the main window into the Two D Scan window for use in 2 D pinhole scans See Section 6 Angular Displacement ALT F7 Opens the Head Setup and Options dialog box to allow input of distance z from the source and angular unit setting for angular beamwidth measurements See Section 4 3 1 for additional detail Accumulation Averaging Dialog ALT N Opens the Accumulation Averaging dialog box See Section 4 3 1 Average
92. s shown in red e The relative heights of the measured and Gaussian profiles is determined by equalizing the areas under the measured profile and the Gaussian profile and then setting the taller profile to 100 e To normalize both profiles to 100 press F6 and disable Auto Gauss Peak e The clip levels are shown in green and labelled in white Pressing X or Y on the keyboard will cause the program to display only that profile Pressing B will cause the program to show both profiles side by side Ctrl 3 BBE Se cee toggles between a wider profile display _ __ and the 2D and 3D displays cane as a ee 9 ce ee E E a Power 21 1 Delta 12 91 um BeamScope P5 4 15 4 2 BeamScope Functions Click and drag the cursor from one point to another on a profile to show the lateral distance between the points and the percent of total power between the points This is useful in measuring beam features You may display the profile s in a logarithmic form by Background color right clicking in the plot area and selecting one of the log ranges This is especially useful for viewing the noise floor or the normally hidden low intensity w ertical Grid structure in the wings Use thick pens slower v Show clip level In such instances it may also be Linear mode useful to press Rg Logl0 30dB F6 disable Auto Logi0 40dB Search and Logi0 50dB manually set the scan range wider Plot History th
93. s which you wish to test enter the Minimum and Maximum values and click to enable the appropriate test boxes Once you have selected the required parameters for pass fail testing click Yes When you resume profiling values will display in Green for Pass Red for Fail and White for Invalid unless you have changed them Section 4 2 2 below 4 8 BeamScope P5 BeamScope Functions 4 2 2 Button Colors Setup Normally the values are shown in black on a gray background turning to a value if Normal Pass Fail Invalid Background the software deems the value Invalid If the value is Tested it will print in the Pass or Fail color The Normal Pass Fail Invalid and Background colors can be customized by the 4 2 user by right clicking the screen area Then select the desired text and button colors Button Colors Setup To choose a button color other than the defaults click on the color patch and a Color dialog box appears offering 48 Basic colors and an almost infinite variety of Custom colors t is strongly suggested that you stick to the default colors or the Basic colors and avoid multi hued and hence confusing screen layouts In particular do not change the background color to a default or chosen color used to display values 4 2 3 Button Areas and Help Hints All areas of the BeamScope P5 screen having a 3 D beveled edge appearance or that display data may also be Windows buttons and
94. scnina inn 3 2 4 Practice with the Software 3 2 5 Log the Data 3 2 6 Short Cuts Table of Contents 4 un A BEAMSCOPE FUNCTIONS seessesessssessseccssecossecesseccosseoossecossecoosecooseecoseecooseoooseeooseeocse L 4 1 THE MAIN SCREEN ere ereeeeee eee eee rire eee eee rire eee eee 4 2 4 1 1 Pull Down Menuis rie i N iene cala 4 3 4 1 2 The Button Bar Laino Bibi lai 4 6 4 2 MAIN SCREEN SECTIONS sseerccrericeeeeieeeceee 4 2 1 Pass Fail for QA and Production Testing 4 2 2 Button Colors Setup RE ae 4 2 3 Button Areas and Help Hints csscscsssssssssssesessssveveseveveneseteseneteeeeeneneneeeneeees 4 2 4 Ellipticity Bultolt ea ile on ELI ana 4 2 5 Centroid Button due sai ERRONEA 4 2 6 Beam Wander ButtOnccccccccccccscsscsccssesssscsesesecsssesessssssesessseeseseseessseseseeeseeseneeees 4 2 7 Gain and Power ButtOar cccccccscssesscssessesssesessssesesesscsesesessesesessesssssesenenseseseeeeeess 4 2 8 Gaussian Fit Button sn a CORRO 4 2 9 Head Status guccia de 42 10 2D View buttoh c lena ah ALLE E aaa 4 2 11 3D View Button 4 2 12 Beam Widths Buttons 4 2 13 Beam Profiles Area sa ses EEEN 42 14 SCOTCH PEE T AE A A E 4 3 PULL DOWN MENUS ADDITIONAL DETAILS 4 3 1 Options Menu ae 4 3 2 Log Menti lana aaa 4 3 3 SOLU EEE E E E E E ouaneseuidneceasbeoapacentsieessnnes 4 4 SLIT MODE
95. slit pair or pinhole in a plane orthogonal to the beam axis The energy transmitted by the aperture s falls upon a silicon detector and is measured as a function of lateral slit position Germanium and Indium Arsenide detectors are employed for the longer wavelengths In Slit Mode the normal mode of operation the slit is much smaller than the beam diameter In Knife Edge Mode the slit must be wider than the beam diameter The pinhole single slit or XY slit pair sits in a fixed position in front of the detector All the energy whether passing through one slit pinhole or two slits falls upon a single detector or upon two detectors connected in parallel The slit plus detector is carried on a rectangular moving carriage which rides on precision linear bearings in a plane set orthogonal to the beam axis The carriage is driven by a taut stainless steel band The center section of the band wraps round and is locked to a capstan on the shaft of a Sphase stepper motor Similar drive principles are employed in some disk drive heads The stepper motor is driven in micro stepping mode at 51 200 steps per revolution resulting in sub micron linear steps of the moving carriage The minimum scanned range is 120 um The probe is driven to scan region s defined by the search routine The search routine actively centers the scanned region about the centroid of the beam profile s and automatically adjusts the width s of the scanned region s For
96. ssembly Remove the current slits and place them in a labeled box Screw the new aperture plate into place on the head Remember to enter the slit details when you get to Section 3 2 2 of these instructions Sito If you need to change the slits click on this button and the probe will come out alit Eye Safety Put on your laser safety goggles before you turn on the laser Mount the BeamScope head in a rigid manner See Section 2 4 such that the probe will intercept the laser beam and will move in a plane perpendicular to the beam axis If the beam profile is elliptical and you are using dual X Y slits set the head such that the slit axes correspond to the beam axes For beam below 50 um it is highly recommended to mount the BeamScope vertically with the probe pointing down in order to minimize vibration that might degrade the measurement Double click the BeamScope icon to start the software The head will make a buzzing sound fora few seconds as the software starts up and verifies the physical end stop This is normal and is not a problem The main screen display Section 4 2 should appear G mene iX de Z gt Dis Lu Sem Dat tie AP y a 3 10 BeamScope P5 Quick Start Tutorial 3 2 2 Head Setup and Options Press F6 and fill in the Head Setup and Optionsdialog box as per section 4 3 3 The most common configuration values are those shown below Make sure that your Setup screen valu
97. terms of a measured diameter at distance z from the beam waist M2 Therefore any system that claims to measure M must adequately measure the waist diameter 2W z versus z over an appropriate range of z See Section 3 It is important to understand that at any given wavelength a given value of M does not define a single curve From equation 3 it is apparent that a single value of M defines a family of curves with a constant 2W product To better illustrate this point Figure 2 shows the curves for five different 1064 nm beams with the same M value of 3 but with waist widths 2Wo of 5 10 15 20 amp 25 um and therefore different values of Figure 2 Curves with Constant M but with Differing Waist Widths amp Divergence z microns 2W 100 75 50 25 0 25 50 75 100 z microns To reiterate this point Curves with identical divergence or with identical beamwaist 2Wo do not necessarily have identical M values Curves with identical M do not necessarily have identical divergence or identical beamwaist diameter Figure 2 emphasizes the necessity of measuring both i e 2W z versus z and 2Wo in order to determine M BeamScope P5 A 5 App Appendices If either side of the beam waist region is inaccessible for example within or at the end of the laser housing or within a closed optical chain then an ancillary optic must be used to form a waist region See Sections 3 3 and 3 4 2 1 Asymmet
98. the operating status of the BeamScope scan head and has no other function X RY axis Standby 4 12 BeamScope P5 BeamScope Functions 4 2 10 2D View button This area is used to display a derived 2D plan view interpretation of the beam profiles It is meant to be used as visualization tool The algorithm assumes that the measured X profile is the same for all values of Y and that the measured Y profile is the same for all values of X since this is the only reasonable reconstruction of the information contained in two orthogonal scans If only X or Y has been scanned the software assumes the X amp Y profiles to be the same and generates a pseudo reconstruction with 2D symmetry Click and drag anywhere in the 2D display area to generate a yellow bordered zoom box that defines a zoomed region of the displayed profile widths and of the 3 D scan The zoomed 3D scan dimension will correspond to the long side of the zoom box Click again to cancel this zoomed region The zoomed in region is also cancelled whenever a new scan is started Double click on the 2D area to alternately swap the 2D view with the larger area normally occupied by the 1D profiles 4 2 11 3D View Button This area is used to display a derived 3D view Angle 6 Tilt 20 interpretation of the beam profiles It is meant to be z used as visualization tool The algorithm assumes that the measured X profile is the same for all values of Y and that the measu
99. these steps 1 Read the header BOOL stat file Read amp BeamHeader sizeof BEAMHEADER sizeof BEAMHEADER 2 Verify that it is a BeamScope P5 data file stat stremp BeamHeader lead BeamScope Beam Data P5 0 3 Read the profiles BEAM _P5 Beam0 Beam1 if BeamHeader Size 0 file Read amp Beam0 BeamHeader Size 0 if BeamHeader Size 1 file Read amp Beam1 BeamHeader Size 1 4 Example to access data int w 0 int clip int 135 Beam0 Peak for int i 0 i lt Beam0 Count i int data Beam0 Datali if data gt clip w float Width Beam0 StepSize w A if Beam0 Slits 2 Width Width 70710678 dual slits pp float Slit Beam0 SlitSize D Il To deconvolve Width sqrt Width Width Slit Slit WARNING For clarity the above code is OVER simplified IMPORTANT NOTE BeamScope P5 Log files follow the same format as above except that many BEAM _P5 data structures may be present so get the file length and load data until the file is exhausted BeamScope P5 A 15 INDEX IMPORTANT Chapter 3 references are part of the QuickStart Tutorials Chapter 4 sections are almost always the most comprehensive reference A _ refers to pages in the Appendices A Aim 3 12 4 17 Alt key Short cuts 3 14 Alphanumeric key Short Cuts 3 14 Analyze Profiles 4 21 Angular Displacement 4 19 Apertures 4 24 also see Search Average 4 4 Accumulation Avera
100. tion both Auto Manual Gain Dialog Ea electrical and software ees derived required to display the profile the default display mode Manual Gain Aperture 1 10 dB 10 dB 4 g gt 10 dB gt Manual Gain being normalized form This gain is expressed in dB 10 log 9 of the linear valie of di ain _ Force Aperture to equal Aperture Auto Gain normal Manual Gain Aperture 2 10 dB is the default selection 10 dB 4 mr gt 10 dB Manual Gain allows the user to set the gain in Copy current gains Close the slide boxes and keep it constant e Ifthe gain is set too low the profile will not normalize on the display e Ifthe gain is set too high the profile will saturate and the results will be in error Force Aperture2 to equal Aperture does precisely that Note that for a highly elliptical beam it does not make sense to do this Copy current gains does exactly that It copies the current gains to the sliders and allows these to be set as manual gains In many instances it can be helpful to turn of the software normalization To do this press F6 and uncheck the Normalize Profiles box in the upper right of the dialog box The user can set manual gain if so desired Press Alt Ato open the dialog box 4 18 BeamScope P5 BeamScope Functions Scanning plane Full divergence or other angle source 4 3 z Angular Displacement ALT F7 Angular Displacement is calculated by the BeamScope P5 soft
101. tted profile click drag and release the mouse The percentage of the total power within the region is displayed together with a Delta measurement in microns corresponding to the horizontal width of the region Selecting the single profile allowed you to do this with maximum resolution Enter Ctrl 3 and b to display both profiles and their 2 D and 3 D representations 3 1 8 Additional Profile Views Place the cursor on one of the two profile plots and click the right mouse button A menu appears allowing you to customize and or select various modes Logarithmic mode in particular allows you to examine deep wings of the profile and assess the background noise level Try selecting a Log10 scale Later on when you are taking real data the Plot History can be interesting if your laser is noisy 3 1 9 2 D and 3 D Views If the 2D and 3D images are not already visible enter Ctrl 3 These are the 2D and 3D images are only visualization tools see Section 4 2 10 but they are also fun and useful Place the cursor on the 2D image and click and drag a rectangle You have just zoomed in on the profiles and the 3D image Now click on the 2D image and cancel the zoom Double click the 3D or 2D image and it swaps panes with the profiles Place the cursor on the 3D image click and drag to change the view of the 3D image Side to side motion rotates the image Up down motion changes the viewed tilt angle Now click the 3D image with the RIGHT mous
102. vel By pressing the ends of the stage control bar you can single step the stage from end to end pecs an tn de p M2 Stage 4 957 21 6mm gt Ensure that the two ends of the travel indicated by the downward pointing white arrows are at the two extreme ends If one is not click that end of the bar and the stage will move there Once it is there click the Set End button Then HOME the stage if it is not already there BeamScope P5 5 5 5 2 M Accessory 5 3 OPERATION 1 2 3 4 5 6 7 8 5 6 Press F6 and verify that the Head Setup and Options dialog box looks identical to that shown in Section 3 2 2 except that Slit size Wavelength or Lens to slits nearest distance may be different from those shown if they are known to be different To measure the Lens to slits nearest distance mm set the stage at the 7 HOME position and set the BeamScope probe head at the Aim position Aim Enter the Lens to slits nearest distance in the Head Setup and Options dialog box This Lens to slits nearest distance equals The distance in mm that you measure from the back of the lens mount to the front surface of the slit mount Plus 23 0 mm The distance shown on the label on the lens The distance 0 5 mm from the principal plane of the lens to the back of the mount Plus 0 75 mm The distance between the slits and the front surface of the mount Two lines below Beam Widths on the main screen if Var
103. w all of the RA profiles in the buffer and scan through them by passing the cursor over them Press it now The dialog box below should appear Profile 1 of 92 n 91 x Image cursor position Select profile to be viewed Note that the first image is highlighted it is the most recent one the one that you were just viewing Pass the cursor over some of the thumbnail images As you do the larger image changes to match the image that is being selected The data in the main window is also updated to reflect which thumbnail has the cursor on it Look at the Caption bar at the very top It tells which image is selected and has an n with a value after it When n equals zero that is the most recently scanned profile and n 1 indicate that it is the second most recent profile and so forth Clicking on a recent image Click on the n 0 image returns you to the main window You have the most recently examined profile on the screen You have now covered how to step through or select a profile set from the data buffer 3 1 3 Beam Centroid Press the Zero button and the x Centroid y values should go to zero Now press the Page Up key and the values will change indicating the difference between the centroids of the first and last profiles It should be in this case a LARGE change since this data 3 4 BeamScope P5 Quick Start Tutorial was taken from a MSquared test where the translation stage caused
104. ware using the known user entered distance Z between the source and desired clip level The clip level refers to the percentage of intensity at which the angle is defined as the beam is diverging Since the BeamScope scans in a linear motion the linear scan data is adjusted by an appropriate algorithm to simulate a scan along an arc having its origin at the source BeamScope calculates and displays the Full Divergence Angle Press Alt F7 to toggle the results displayed in the Beam Widths portion of the main screen between normal and angular displacement Beam Widths 50 49e 3 rad 13 5 Clip 52 53e 3 rad 50 49e 3 rad 13 5 Clip 52 53e 3 rad To change Z press F6 to open the Head Divergence Angle Z distance Setup and Options dialog box Look at the lower left area of the box If Z was set Z Distance mm at zero the box will open automatically l bapan e Haas CNA Enter the Z value in mm Select Degrees Radians or N A N A Numerical Aperture Sin half angle BeamScope P5 4 19 BeamScope Functions Accumulation Averaging Dialog ALT N Accumulation Averaging Dialog EJ Samples accumlated 0 Opens the Accumulation Averaging Dialog box See page 44 for a running average During Accumulation the gain is locked Click on Enable to start accumulating an averaged profile with no limit on the number of samples n which are averaged The displayed profile and beamwidths are the average of the
105. y the product M of divergence and waist diameter measured in this manner is conserved for a generalized non Gaussian beam A mixture of TEM modes And this product is only conserved in an optical system which does not truncate the beam The Gaussian equivalent beam diameter is only appropriate for a TEM 09 laser beam Q Five separate measurements of diameter must be averaged Q Any slit pinhole or knife edge scanner must scan the beam in a plane at right angles to the zaxis Rotating drum scanners with slits or knife edges in tangential planes around the circumference scan in a circular trajectory rather than a plane Not an issue for CCD camera based systems A 6 BeamScope P5 Appendices 3 M Measurement Rules of Thumb and Sanity Checks M is not a quantity that can be measured to the last fraction of a percent An M value accuracy of 10 is often acceptable 5 is good and better than 5 is exceptional What accuracies need to be achieved in the raw measurements in order to measure accurately 3 1 Accurately Measuring the Waist From equation 4 and figure 1 it is apparent that in order to measure 2W accurately a measurement must be made within a certain fractional distance z zg of the waist For the fractional error in 2Wo to be less than g the measurement must be made within a normalized distance from the waist given by Ref 2 ele a E g For g lt 0 01 1 z zr lt 0 14 14 Theref
106. your focused laser spot diameter is larger than calculation predicted O You are tasked with measuring M and or somebody gave you a copy of the ISO 11146 standard 8 D Because M is an invariant property of a laser beam propagating through an optical system M may therefore be used to describe the beam at any point in that optical system The optical system must neither aberrate nor truncate the beam Whichever reasons apply if you are to ensure that your measurements are valid it is useful even necessary to understand what you are measuring and the limitations of the technique This Note attempts to comprehensively yet concisely address Q The concept of M O M formulae and how it is measured Q Useful Rules of Thumb and Sanity Checks 2 M Definition amp Formulations M is a dimensionless parameter that characterizes the degree of imperfection of a real world laser beam The lower the value of M i e the closer the beam is to diffraction limited TEMo perfection the more tightly the beam can be focused to a small spot No laser beams are perfect Due to limitations of the optical cavity the lasing medium and or the output ancillary optics most beams are not the perfect diffraction limited Gaussian profile pure TEMy mode described in textbooks Complex beams can contain multiple TEM y mode contributions leading to high values of M Even a good laboratory HeNe laser has

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