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OPA-800C - Spectra

1. A 1 Appendix B OPA 800C Wavelength Tables o oooooooooooooo B 1 Notes Report Form for Problems and Solutions List of Figures Figure 1 1 The OPA 800C Optical Layout 0 0 0 eee ene 1 1 Figure 1 2 The OPA 800C Beam Path 0 cc eee eee nes 1 2 Figure 2 1 These CE and CDRH standard safety warning labels would be appropriate for use as entry warning signs EN 60825 1 ANSI 4 3 10 1 2 0 0 cee 2 2 Figure 2 2 Folded Metal Beam Target 0 ccc eee eee eee 2 2 Figure 2 3 OPA 800C Radiation Control Drawing 0 0 eens 2 4 Figure 3 1 Optical frequency three wave interaction proCceSS 0 eee 3 2 Figure 3 2 Optical Parametric Amplification 0 0 3 3 Figure 3 3 Typical OPA 800C System Layouts 0 ees 3 6 Figure 3 4 Wavelength vs Phase Matching Angle of Type and Type II Crystals 3 7 Figure 3 5 Typical Output Tuning Curves of an OPA 800CF 1 2 0 0 ee 3 8 Figure 3 6 Typical Output Tuning Curves of an OPA 800CP 1 0 ee 3 8 Figure 3 7 Typical Output Tuning Curves for Wavelength Extensions for an OPA 800CF 1 3 9 Figure 3 8 Typical Output Tuning Curves for Wavelength Extensions for an OPA 800CP 1 3 10 Figure 3 9 Double pass single BBO crystal OPA 800CFP 0 0 0 0 3 11 Figure 3 10 Mechanical Layout of the OPA 800CF 0 06 3 13 Figure 3 11 Mechanical Lay
2. Monitor and Video Analyzer Variable Attenuator m 95 Attenuator Mo Output from OPA 2 a Beam Splitter To Experiment Table Layout Display Figure 6 2 A Typical Monochromator CCD Camera Setup Note a Verify your monochromator can measure the wavelength you have selected 3 Set the OPA SOOCF crystal angle micrometer to the position corre sponding to the desired operation wavelength Figure 6 3 gives the approximate relationship between the OPA 800C signal output wavelength and the crystal angle micrometer setting 6 3 OPA 800C Ultrafast Optical Parametric Amplifier Note a 37 36 35 34 33 32 BBO Crystal Angle Micormeter Position mm 1 1 1 2 1 3 1 4 1 5 1 6 Signal Wavelength um Figure 6 3 Typical Signal Wavelength vs BBO Crystal Angle Position The relationship between the wavelength and micrometer setting may change due to alignment changes Figure 6 3 is only intended to be used as an approximate reference 4 Adjust DELAY 2 to optimize OPA SOOC output This will slightly shift the output wavelength by a few nm 5 Adjust the micrometer to obtain the exact desired wavelength Iterate between adjusting the crystal angle micrometer and DELAY 2 to obtain the optimum power at the desired wavelength To select the idler beam wavelength measure it with a spectrometer or if you know the pum
3. A ah rd a re Figure 7 10 Mechanical Layout of the OPA 800CF Arranged for DEM 7 12 OPA 800C Ultrafast Optical Parametric Amplifier Polarization Summary The polarization of each possible output beam is listed in Table 7 1 for your convenience assuming you use the configurations shown in this man ual Table 7 1 Output beam polarization from OPA 800C Output o Q 0 29 20 40 4o Armara Bexma 0a DFM Polarization V V V V H H V H H H 1 V vertical H horizontal Chapter 8 Equipment Required Maintenance OPA 800C optics are made by vacuum depositing microthin layers of mate rials of varying indices of refraction on to different substrates If the surface 1s scratched to a depth as shallow as 0 01 mm 0 0004 in the operating efficiency of the optical coating can be reduced significantly and the coat ing can degrade Energy losses due to unclean optics will reduce the output power Dirty optics can be potentially disastrous due to the high power optical pulse inside the OPA 800C A small speck of dust or other contaminant on the optics can produce permanent optical damage which can cause the OPA SOOC to fail Cleanliness is essential and you must apply laser optics main tenance techniques with extreme care and attention to detail Remember clean is a relative description nothing is ever perfectly clean and no cleaning operation can ever completely remove contaminants Clean ing is a process
4. Dot at eth TCE a ADN A Ble Gl A Figure 3 12 Mechanical Layout of the OPA 800CFP OPA 800C Ultrafast Optical Parametric Amplifier Specifications Table 3 1 OPA 800CF Specifications Pump Pulse Output Performance Requirement Signal Output A 1 3 um Idler Output A 2 08 um Pulse Energy 1 0 mJ 75 uJ 35 uJ 0 5 mJ 35 uJ 20 uy 0 3 mJ 18 uJ 10 uJ 0 7 mJ at 50 fs 53 uJ 25 uJ Pulse Width lt 130 fs lt 130 fs lt 130 fs Tuning Range 800 nm 5 nm 1 10 1 60 um 1 60 um 3 00 um Repetition Rate Nominal 1 5 kHz 1 kHz 5 kHz Energy Stability lt 3 lt 3 Polarization Horizontal Linear Vertical Due to our continuous improvement policy specifications are subject to change without notice and only apply when the OPA 800CF is pumped by a Spectra Physics Tsunami Millennia or BeamLok and Merlin Spitfire Hurricane system For 54 dual OPA system contact Spectra Physics The pump pulse is the output of the Spectra Physics Spitfire Hurricane with a pulse width of lt 130 fs at 800 nm For the OPA 800CF pumped by the Spitfire Hurricane USF lt 80 fs at 800 nm output energy is 75 of the standard system When pumped by the Spitfire Hurricane SOFS lt 50 fs at 800 nm the output energy is 70 of the standard system 5 Alm pumped OPA 800CF 1 is normally configured for a standard 1 kHz Spitfire Hurricane A 0 5 mJ pumped OPA S00CF 0 5 is usually configured for dual OPA operation A 0 3 mJ pumped OPA
5. Figure 7 5 Schematic layout of the FHG of the signal OPA 800C Options O ff a E we XE D LO EY NES Pee AS 4 0 y T99 o OO O 1 SS XP RE QO A O SS a PS SOL O O BBO el O ORLY a Al X N SS N I K A OOo i S N Figure 7 6 Mechanical Layout of the OPA 800CF Arranged for FHG of the Signal 7 7 OPA 800C Ultrafast Optical Parametric Amplifier To avoid pulse broadening due to strong dispersion and high absorption and to have the best spectral purity in this UV wavelength range two sets of dichroic mirrors are used to separate the FHG beam from the signal SHG and signal beams Each set covers a specific wavelength range as indicated These mirrors are designed for 45 incidence angle use P can be removed to achieve the highest output energy possible The signal FHG beam is horizontally polarized and it exits from the port as shown in out line drawing Figure 3 13 Sum Frequency Mixing Option SFM The SFM option allows you to mix the signal or idler with the residual pump beam This sum frequency mixed output covers the wavelength range from 480 to 533 nm or from 533 to 600 nm by mixing the signal or the idler with the residual pump respectively In order to mix the residual pump beam with the signal or idler the lower mirror dichroic on the PS mount must be out of the beam path to allow these beams to propagate to the conversion c
6. Possible Causes Corrective Action Check the two collimation lenses Center the two lenses with the signal and idler beams Signal and or idler spectra have side Realign the OPA and white light generator lobes DELAY 1 and 2 are not optimized Optimize them Pump pulse has wrong spectrum Check the pump pulse spectrum shape and correct it if neces sary Service and Repair Replacement Parts OPA 800CF Description Designation Part Number AgGas DFM Crystal DFM Option 0452 9891 0451 5070 AgGaS DFM Crystal DFM Option 0453 3610 BBO Crystal Coated with mount BBO xtal 0453 6020 glued assy 0451 5120 BBO Crystal Coated with mount BBO xtal 0454 7170 glued assy 0453 3620 BBO Crystal Type 0 7 mm HG BBO 3 0451 5062 BBO Crystal Type 0 5 mm HG BBO 3 0451 5061 BBO Crystal Type II 0 5 mm SFM 0451 8301 Beam Splitter BS G0020 032 Beam Splitter BS 0450 9840 or 0450 9850 Beam Splitter OPA 800C dual assy G0501 002 Dichroic 1 D 4 G0501 001 Dichroic 2 D PS G0502 001 Dichroic Mirrors DDM 480 600 nm SFM DDM _3 G0020 036 Dichroic Mirrors 300 360 nm HGIl G0020 035 Dichroic Mirrors 360 400 nm HGIl 3827 1547 Dichroic Mirrors 400 600 nm HGI G0020 036 High Damage Mirror 800 nm Ra 3827 1552 Lens BaF FL 250 mm Options HG DFM 3827 1544 Lens Fused Silica FL 350 250 mm Options HG DFM 3827 1687 3827 1543 Lens Opt PLN CNV L 3827 1532 Lens Opt PLN CNV 25 5D La 3827 1533 L
7. and the WLP white light plate see Figure 4 1 Adjust BS to center the beam on waveplate WP and align the beam along the center line of the white light generator WLG arm 6 3 cm above and parallel to the base plate use an alignment card Rotate the WP to minimize the energy after the polarizer Move the business card from the front of the WLP to the front of CL Move the FL lens as close to the WLP as possible then move 1t back and forth with your fingers and look for white light WL to be gener ated within the WLP on the card If you do not see the WL signal optimize the Spitfire Hurricane com pressor delay see Spitfire Hurricane user s manual and repeat Step 5 If you still cannot find the WL signal gradually increase the pump energy to the WLP adjust the WP and repeat the last two steps until you generate WL Typically 1t needs lt 3 uJ energy pulse depending on the pulse duration By translating the FL and optimizing the pulse duration and pump energy through WP you should be able to get a symmetrical WL beam with a bluish green spot at the center and a yellowish ring around 1t for use as a seed beam Note Note S i OPA 800CF Installation and Alignment If you have difficulty generating WL check the pulse duration of the Spitfire Hurricane output to see if it meets the requirement for pumping the OPA 800CF see specifications at the end of Chapter 3 If the WL has a bright spot that moves around o
8. 4 AA AMAA ANA HAN 114 1 4 Signal Idler SHG SHG FHG FHG DFM SFM P S SFM P I Signal Idler Signal Idler um um nm um nm nm um nm nm 1 090 2 870 545 0 1 44 272 5 717 6 1 76 1 100 2 803 550 0 1 40 275 0 700 8 1 81 1 125 2 653 562 5 1 33 281 3 663 2 1 95 1 150 2 524 575 0 1 26 287 5 630 9 2 11 1 175 2 411 587 5 1 21 293 8 602 8 2 29 1 200 2 312 600 0 1 16 300 0 578 0 2 49 480 589 1 225 2 225 612 5 1 11 306 3 556 2 2 73 484 583 1 250 2 147 625 0 1 07 312 5 536 7 2 99 488 577 1 275 2 077 637 5 1 04 318 8 519 2 3 30 492 572 1 300 2 014 650 0 1 01 325 0 503 4 3 67 495 567 1 325 1 957 662 5 0 98 331 3 489 1 4 10 499 563 1 350 1 904 675 0 0 95 337 5 476 1 4 64 502 558 1 375 1 857 687 5 0 93 343 8 464 2 5 30 506 554 1 400 1 813 700 0 0 91 350 0 453 3 6 14 509 550 1 425 1 773 712 5 0 89 356 3 443 2 7 26 512 546 1 450 1 736 725 0 0 87 362 5 433 9 8 81 516 543 1 475 1 701 737 5 0 85 368 8 425 3 11 10 519 539 1 485 1 688 742 5 0 84 371 3 422 0 12 35 520 538 1 500 1 669 750 0 0 83 375 0 417 3 14 81 522 536 1 525 1 639 762 5 0 82 381 3 409 8 525 533 1 550 1 611 775 0 0 81 387 5 402 8 528 530 1 575 1 585 787 5 0 79 393 8 396 3 531 527 1 600 1 560 800 0 0 78 400 0 390 1 533 524 B 3 OPA 800C Ultrafast Optical Parametric Amplifier Table B 4 Corresponding OPA 800C Output Wavelengths for an 810 nm Pump Input Not for specified performance Ag i AsHG AsHG FHG FHG ADEM ASM AsFM WA TA A 2 2 2 A 4 2 4 VAI
9. angle adjust DELAY 2 to bring them together You should see the same pat tern for a wide wavelength range Stable ps OPA SOOCP output can be obtained with some optimization If you can operate the OPA SOOCP in a regime that generates about 20 40 uJ of output signal idler with the white light seed blocked it is a good indi cation that it is in the saturation regime This amount of OPG will be sup pressed substantially when it is seeded with white light WL Stable WL generation and optimal temporal overlaps between WL and pump beams are crucial for stable OPA SOOCP outputs At some strong water absorption wavelengths the OPA SOOCP output becomes unstable and a very small amount of detuning can stabilize the output Sometimes 1 2 ns changes in the switch in and switch out times of the of the Spitfire SDG will stabilize the pump pulses which will stabilize your OPA SOOCP output The absorp tion lines can show up in the spectrum as deep notches This concludes the operating procedure 6 7 OPA 800C Ultrafast Optical Parametric Amplifier Chapter 7 OPA 800C Options In addition to the fs to ps or ps to fs OPA 800C conversion kit Spectra Physics provides the following options to extend the wavelength coverage for fs and ps OPAs e Harmonic Option I e Harmonic Option I e Sum Frequency Mixing SFM of the pump with the signal or the idler e Difference Frequency Mixing DFM of the signal with the idler These options provid
10. but also in service facilities that get your instrument repaired and back to you as soon as possible Spectra Physics maintains major service centers in the United States Europe and Japan Additionally there are field service offices in major United States cities When calling for service inside the United States dial our toll free number 1 800 456 2552 To phone for service in other coun tries refer to the Service Centers section located at the end of this chapter Order replacement parts directly from Spectra Physics For ordering or shipping instructions or for assistance of any kind contact your nearest sales office or service center You will need your instrument model and serial numbers available when you call Service data or shipping instruc tions will be promptly supplied To order optional items or other system components or for general sales assistance dial 1 800 SPL LASER in the United States or 1 650 961 2550 from anywhere else This warranty supplements the warranty contained in the specific sales order In the event of a conflict between documents the terms and condi tions of the sales order shall prevail Unless otherwise specified all parts and assemblies manufactured by Spectra Physics except optics are unconditionally warranted to be free of defects in workmanship and materials for a period of one 1 year following deliv ery of the equipment to the F O B point All optics and crystals are war r
11. 1 1 12 2 2 A 4 2 4 VAA1M MIA HINA 1 1 Ap 1 Signal Idler SHG SHG FHG FHG DFM SFM P S SFM P l Signal Idler Signal Idler um um nm um nm nm um nm nm 1 000 3 545 500 0 1 77 250 0 886 4 1 050 3 033 525 0 1 52 262 5 758 3 1 100 2 681 550 0 1 34 275 0 670 3 1 125 2 543 562 5 1 27 281 3 635 9 1 150 2 424 575 0 1 21 287 5 606 1 1 175 2 320 587 5 1 16 293 8 580 1 1 200 2 229 600 0 1 11 300 0 557 1 2 60 480 578 1 225 2 147 612 5 1 07 306 3 536 8 2 85 484 572 1 250 2 074 625 0 1 04 312 5 518 6 3 15 488 567 1 275 2 009 637 5 1 00 318 8 502 3 3 49 492 562 1 300 1 950 650 0 0 98 325 0 487 5 3 90 495 557 1 325 1 896 662 5 0 95 331 3 474 1 4 40 499 553 1 350 1 847 675 0 0 92 337 5 461 8 5 01 502 548 1 375 1 803 687 5 0 90 343 8 450 6 5 80 506 544 1 400 1 761 700 0 0 88 350 0 440 3 6 83 509 541 1 425 1 723 712 5 0 86 356 3 430 8 8 23 512 537 1 450 1 688 725 0 0 84 362 5 422 0 10 28 516 533 1 475 1 655 737 5 0 83 368 8 413 8 13 54 519 530 1 485 1 643 742 5 0 82 371 3 410 7 15 44 520 529 1 500 1 625 750 0 0 81 375 0 406 3 19 50 522 527 1 525 1 597 762 5 0 80 381 3 399 2 525 524 1 550 1 570 775 0 0 79 387 5 392 5 528 521 1 575 1 545 787 5 0 77 393 8 386 3 531 518 1 600 1 522 800 0 0 76 400 0 380 5 533 516 B 2 OPA 800C Wavelength Tables Table B 3 Corresponding OPA 800C Output Wavelengths for a 790 nm Pump Input Not for specified performance Ag i sHG AsHG FHG FHG ADEM AsFM AsFmM WAN A A 1 12 2 2 A
12. 1145 Agl2 2 2 A 4 2 4 VAAM UA HA 1M1M 1M Signal Idler SHG SHG FHG FHG DFM SFM P S SFM P l Signal Idler Signal Idler um um nm um nm nm um nm nm 1 000 4 714 500 0 2 36 250 0 1178 6 1 050 3 850 525 0 1 93 262 5 962 5 1 100 3 300 550 0 1 65 275 0 825 0 1 125 3 094 562 5 1 55 281 3 773 4 1 150 2 919 575 0 1 46 287 5 729 8 1 175 2 770 587 5 1 38 293 8 692 4 1 200 2 640 600 0 1 32 300 0 660 0 2 20 480 629 1 225 2 527 612 5 1 26 306 3 631 6 2 38 484 622 1 250 2 426 625 0 1 21 312 5 606 6 2 58 488 616 1 275 2 338 637 5 1 17 318 8 584 4 2 81 492 610 1 300 2 258 650 0 1 13 325 0 564 5 3 06 495 604 1 325 2 186 662 5 1 09 331 3 546 6 3 36 499 599 1 350 2 121 675 0 1 06 337 5 530 4 3 71 502 594 1 375 2 063 687 5 1 03 343 8 515 6 4 13 506 589 1 400 2 009 700 0 1 00 350 0 502 2 4 62 509 585 1 425 1 959 712 5 0 98 356 3 489 8 5 23 512 581 1 450 1 914 725 0 0 96 362 5 478 5 5 98 516 577 1 475 1 872 737 5 0 94 368 8 468 0 6 95 519 573 1 485 1 856 742 5 0 93 371 3 464 1 7 43 520 571 1 500 1 833 750 0 0 92 375 0 458 3 8 25 522 569 1 525 1 797 762 5 0 90 381 3 449 3 525 565 1 550 1 764 775 0 0 88 387 5 440 9 528 562 1 575 1 733 787 5 0 87 393 8 433 1 531 559 1 600 1 703 800 0 0 85 400 0 425 8 533 556 1 625 1 676 812 5 0 84 406 3 419 0 536 1 541 5 1 650 1 650 825 0 0 83 412 5 412 5 538 8 538 8 B 5 OPA 800C Ultrafast Optical Parametric Amplifier Notes Notes 1 OPA 800C Ultrafast Optical Parametric Amplifier Notes 2 N
13. 2 A Typical Monochromator CCD Camera Setup 0 00 0 eee eee 6 3 Figure 6 3 Typical Signal Wavelength vs BBO Crystal Angle Position 6 4 Figure 6 4 Typical Signal Wavelength vs Grating Angle Position o oo ooooooooo 6 5 Figure 7 1 Mechanical Layout of the OPA 800CF Arranged for SHG of the Idler 7 2 OPA 800C Ultrafast Optical Parametric Amplifier Figure 7 2 Mechanical Layout of the OPA 800CF Arranged for FHG of the Idler 7 3 Figure 7 3 Mechanical Layout of the OPA 800CF Arranged for SHG of the Signal 7 4 Figure 7 4 Configuration for SHG a and FHG b of the idler and SHG of the signal c 7 5 Figure 7 5 Schematic layout of the FHG of the signal o o oooooooonoanonno 7 6 Figure 7 6 Mechanical Layout of the OPA 800CF Arranged for FHG of the Signal 7 7 Figure 7 7 Schematic layout of the SFM of the signal idler with the residual pump 7 8 Figure 7 8 Mechanical Layout of the OPA 800CF Arranged for SFM 0 0c eee eee 7 9 Figure 7 9 Schematic layout of the DFM option 2 00 eee ee 7 10 Figure 7 10 Mechanical Layout of the OPA 800CF Arranged for DFM 20 005 7 11 Figure 8 1 Lens Tissue Folded for Cleaning 0 00 cece ee ee ee eens 8 4 FIgure 8 2 Drop and Drag MeInod aa sodvcbeea A eek eee ee BARA Se eee 8 4 Figure 9 1 OPA 800CF Optics Part Num
14. 800CFP OPA 800C Ultrafast Optical Parametric Amplifier In the second leg the major portion of the amplified beam is split into two pump beams each of which are down collimated to pump the OPA 800C crystal About 15 of the beam is used to pump the first pass or pre ampli fication stage and the remainder is used to pump the second pass or power amplifier stage In the pre amplification stage the pump beam is steered to the OPA 800C crystal using dichroic mirror D which is a high reflector from 750 to 840 nm and highly transmissive for longer wavelengths This dichroic mirror combines the pre amplification pump beam with the white light that 1s generated in the WL arm The white light is temporally over lapped and amplified by the pre pump beam by optimizing DELAY 1 The signal and idler beams generated in the BBO crystal in the pre amplifi cation stage then pass through dichroic mirror D In an OPA SOOCF the amplified idler beam is reflected back through the OPA SOOCF crystal by mirrors WLR and WLR In an OPA SOOCP the amplified idler beam is dif fracted back through the OPA SOOCP crystal by grating G that is mounted on a rotation stage In either case this returned beam provides the seed pulse for the power amplifier stage The power amplifier stage pump beam is steered to the crystal by five mir rors and the 800 nm dichroic mirror D where it is overlapped collinearly with the returning idler signal beam in the BBO crystal
15. Uses listed in the official Journal of the European Communities Environmental Specifications The environmental conditions under which the laser system will function are listed below Indoor use Altitude up to 2000 m Temperatures 10 C to 40 C Maximum relative humidity 80 non condensing for temperatures up to 31 C Mains supply voltage do not exceed 10 of the nominal voltage Insulation category II Pollution degree 2 Table of Contents Preta orar ek te eg a da ee iil CE Environmental Specifications 00 00 cee ees V CE Electrical Equipment Requirements nananana nanana V Environmental Specifications naaa aaa aaae V Warnings saraaa a ad bas ib odas aa xi Standard UNS ta EA a a ee eae xiii ADO MIA tONS nati IA RAE A ad XV Unpacking and Inspections 0000 ee ees xvii Chapter 1 INtTOdU CIONES wee A ee ee 1 1 The OPA S000 SySIOM serna dls Seow A o ba 1 1 CONNORS orar E E A a Be iaa 1 3 AV AllablesOpuOns tad as rial A A da Bete Saeed 1 3 Upgrade From a fs OPA 800CF to a fs ps OPA 800CFP o ococcccoc 1 3 Upgrade From a ps OPA 800CP to a fs ps OPA 800CFP 2 0c es 1 4 Harmon Generation esas ss Hee aw x AA ES 1 4 oFM Sum Frequency Mixing Wo Wo Wo E Wi a a iG aint Fabs poe a dens 1 4 DFM Difference Frequency Mixing W W 0 002 ee 1 5 Chapter 2 Laser SaleWas nd cot cco wena dod bade eaewe iam eeed hae eens 2 1 Precautions for the Safe Operation of Cl
16. beam path about 25 cm after the first BBO crystal and it is mounted so that it is tuned about a horizontal axis the micrometer 1s vertical ue PS LBF Oj 20 o O a Schematic layout of the SHG of the idler Py b Schematic layout of the FHG of the idler 40 Oj BBO P N c Schematic layout of the SHG of the signal BBO 2 BBO Crystal Les Fused Silica Lens PS Periscope 2 Py o Polarizers Lgr BaF2 Lens KG 3 Filter Figure 7 4 Configuration for SHG a and FHG b of the idler and SHG of the signal c 7 5 OPA 800C Ultrafast Optical Parametric Amplifier To separate the FHG from the SHG and idler one set of dichroic mirrors are used to reflect the FHG within the 400 600 nm wavelength range and the mirrors are so marked as shown in Figure 7 4 b Figure 7 2 shows the layout for this harmonic configuration To generate optimum fourth har monic idler energy first optimize the SHG energy then tune the FHG crys tal to generate the highest FHG output at the exit port The FHG pulse is vertically polarized To generate the second harmonic of the signal beam a second cube polar izer P replaces periscope PS and is mounted so that the horizontally polarized light passes through it The two lenses are then removed from both the fs and ps OPAs The 4 mm 0 7 mm crystal used for the idler HG in the OPA SOOCP or OPA SOOCF is used as the SHG crystal for the signal beam This crystal must be kept in
17. divergence in pump beams the focused and collimated beam sizes of your pump beams can be quite different from those used at the factory Therefore while aligning an optic always protect the optics down stream especially the BBO crys tal by keeping the beams at a safe intensity Do not frequently clean the crystals in the OPA BBO AgGaS Most are made of hygroscopic materials You can use Xylene to clean BBO if it is very necessary Do not use methanol or acetone Close and when aligning the white light generator Always let the beam hit the center of the optical elements except where noted Keep the beam height 6 3 cm above the base plate after PS and before PS Use one of the alignment cards provided in this manual Installation OPA 800CF Installation and Alignment Close all the irises in the OPA and block the Spitfire or Hurricane amplifier pump beam in front of periscope PS4 Verify the Spitfire Hurricane output beam 1s 15 9 0 3 cm above and parallel to the optical table and that the beam is directed toward the OPA 800CF Orient the OPA 800CF so that the Spitfire Hurricane output beam 1s perpendicular to the input side panel Figure 4 2 and hits the center of of the chosen input port Block the WL generation pump beam by placing a card in front of the white light generator Remove the window plug and let the pump beam into OPA 800C If you use a beam splitter to separate the beam for other outside requi
18. heath oa Sede achat AAA AAA leva a hel Pc rele Ae eat 7 12 Chapter 8 Maintenance 000 ee 8 1 EQUIPMent Required usada a A town ata rare la ao A a Seiwa ae 8 1 Removing and Cleaning OPA 800C Optics 0 0 0 0 cc ee eens 8 2 Standard Cleaning Procedures 0 ee ee ee eens 8 2 General Procedures for Cleaning all Optics Except the Crystal and Grating ps only 0 ccc eee eee eens 8 3 General Procedure for Cleaning the Crystal 0 0 0 0 ccc eee ee eee 8 5 General Procedure for Cleaning the Grating 0 00 cece ee eee 8 6 Chapter 9 Service and Repair 0 00 cee ee 9 1 TYOUDISSHOOUNG GUIAS 4 45 03 2583 a AAA ASAS wees 9 1 Part POPRA SOOCP ica oo atra dar Sl tia anes atlas eta tte aO 9 2 Pant llPOPA 800CP aso taras iaa tarada td ds as 9 5 Replacement Parts OPA 800CF tos os Aa a SAA A a ds 9 9 Replacement Parts Diagram OPA 800CF o ooccocccc eens 9 10 R placement Parts OPA 800CP coo osos sd loto dd a dd AD acho DA E ae AA A 9 11 Replacement Parts Diagram OPA 800CP o ooccocccco eens 9 12 viii Table of Contents Chapter 10 Customer Service 000 ccc o 10 1 CUSTOMER Servi tecnico rad fo Ren a hese ae A anh ic ak Me ae etki mea de tin B Get eae he we ecb raed cd 10 1 Warrants o re ii aia dd 10 1 Return of the Instrument for Repair o o oooooooooon ee eens 10 2 SENICE Centers rt A RA isa 10 3 Appendix A Pumping an OPA 800CP with Spitfire
19. of tissue in half repeatedly until you have a pad about Y cm square and clamp it in a hemostat Figure 8 1 While folding do not touch the surface of the tissue that will contact the optic or you will contaminate the solvent b Saturate the tissue with toluene or xylene shake off the excess re saturate and shake again Do not use excess solvent The excess might penetrate below the crystal and dissolve the glue which bonds the crystal to the mount The glue can then migrate to the crystal surface and permanently damage it 8 5 OPA 800C Ultrafast Optical Parametric Amplifier c Wipe the surface in a single motion and direction and wait for the solvent to evaporate Do not touch the aluminum holder if possible Be sure that the hemostat does not scratch the crystal surface General Procedure for Cleaning the Grating Warning Only clean the grating with puffs of air Anything else will destroy the grating surface This completes the cleaning procedure 8 6 Chapter 9 Service and Repair This chapter contains a general service and troubleshooting guide for use by you the user It is provided to assist you in isolating some of the prob lems that might arise while using this system A complete repair and or upgrade procedure is beyond the scope of this chapter For information concerning repair by Spectra Physics refer to Chapter 10 Customer Ser vice At the end of this chapter are replacement parts tables
20. or by simple visual observation h Caution U Grating Setup Note a OPA 800CP Installation and Alignment To help find the WL pre amplification use an infrared photodetector placed in front of a card located in front of WLR Otherwise visually examine the amplification a change in WL intensity Generating a rea sonable amount of OPG with the pre amplifier pump beam can help obtain amplification Caution Avoid generating white light in the BBO crystal with the pre amplifier pump beam This can damage the crystal In order to obtain narrow line width output ps OPAs use a grating after the amplification stage to select a narrow portion of the amplified WL spec trum as a seed for the power amplifier stage Since wavelength tuning is primarily performed by rotating both the grating and the BBO crystal around the horizontal axes it is important that the grating be set up cor rectly so the OPA SOOCP can function over the entire tuning range espe cially with automated tuning The grooves in the grating must be parallel to the base plate and the rota tional axis of the grating assembly should be parallel to and in the plane of the grooves and normal to the incident WL beam By carefully following the steps in this section you will be able to correctly align this grating You should not need to perform this alignment often especially once it 1s set up correctly This alignment will slightly affect your wavelength set ting
21. portion of the translation stage so that it is rotated 180 from that shown in Figure 5 7 Figure 5 7 L L Placement for ps and fs Configurations 9 10 11 12 Remove the 1 in curved mirror mount from the base plate grating assembly Figure 5 5 Remove dichroic mirror D from the beam path in front of G Mount the grating mount to the mounting plate on the grating assem bly Install the beam protector BP plate into its position as shown in Fig ure 5 1 OPA 800C Ultrafast Optical Parametric Amplifier 13 If BS is a 1 R beam splitter it must be replaced with a 4 R beam splitter for standard pump pulse energy This completes the fs to ps mechanical and optical conversion Continue with the Alignment section earlier in this chapter To convert your system back to fs operation please see Chapter 4 Chapter 6 Operation Since the OPA 800C is a passive device and is pumped by a Tsunami Mil lennia or Mai Tai with a Merlin or Evolution Spitfire or a Hurricane system described in Chapter 3 the pumping system must be turned on in order to operate the OPA The output of the OPA also depends upon the quality of the pump beams and is sensitive to environmental change Always verify that the output of the pump systems meets specifications before operating the OPA 800C Once the OPA 800C has been installed and aligned the day to day opera tion is consistent and repeatable Provided that nothing is dist
22. the correct mount in order to tune its angle about a horizontal axis The original cube polarizer P used in the harmonic generation of the idler must be rotated to transmit the vertically polarized beam as shown in Figure 7 4 c The mechanical optical layout relative to the base plate is shown in Figure 7 3 The SHG pulse energy 1s optimized again by adjusting the BBO crystal phase matching angle micrometer The SHG signal is vertically polarized Harmonic Generation Il Option HGIl Harmonic option HGII permits the generation of the fourth harmonic of the signal in addition to the other harmonics generated with the HGI The wavelength coverage is from 300 to 400 nm The first crystal stage is con figured as shown in Figure 7 4 c Figure 7 5 and Figure 7 6 show the opti cal mechanical layout for this option To generate the FHG of the signal the OPA SOOCP uses a 3 mm thick type I BBO crystal for the second crystal stage whereas the OPA 800CF uses the same 0 5 mm thick crystal used in Figure 7 4 b to generate the FHG of the idler The two lenses are again removed in both the fs and ps OPAs The FHG crystal is placed in the beam about 25 cm after the SHG crystal and is angle tuned about a vertical axis as shown in Figure 7 5 In some circumstances better forth harmonic signal output might be obtained by using a flat silver mirror in the WLR position BBO Y BBO 3 BBO Crystal Po Polarizer DM _3 uv Dichroic Mirrors
23. thus you may have to record the grating angle vs wavelength when you are done It is repeatable to better than 20 cm Block the pre amplifier pump beam in front of L to keep it from ampli fying the WL 1 Mount the grating mount to the upper 8 32 threaded holes in the mounting plate so that the grating mount is placed at the ps alignment notch as shown in Figure 5 5 Grating Angle Micrometer a Mounting Screws 2 from this side PS Alignment Notches Vertical Adjust Grating Mounting Plate Figure 5 5 OPA 800CP Grating Assembly 5 7 OPA 800C Ultrafast Optical Parametric Amplifier Set the grating micrometer position to the number found on the OPA S00CP Final Test Performance Summary for 1 3 um or see Figure 6 4 Rotate the grating Figure 5 5 relative to the grating mount so that the diffracted WL is in a plane that is perpendicular to the base plate Skip this step if the plane is already perpendicular to the base plate Reposition the whole grating assembly so that the WL is diffracted back to the outer half of the BBO crystal as shown in Figure 5 1 Rotate the grating mount up and down by pressing on the micrometer pad and adjusting the grating horizontal control so that the diffracted colors move in a vertical line perpendicular to the base plate 1 e when viewed on a white card there is no lateral shifting of the dif fracted beam while changing the grating angle If the diffracted beam doe
24. to shipment your OPA 800C left Spectra Physics in good condition Upon receipt of your system immediately inspect the outside of the shipping containers If there is any major damage such as holes in a box or cracked wooden frame members insist that a rep resentative of the carrier be present when you unpack the contents Carefully inspect your system as you unpack it If you notice any damage such as dents scratches or broken knobs immediately notify the carrier and your Spectra Physics sales representative Keep the shipping containers If you need to return the system for upgrade or service the specially designed shipping containers assure adequate pro tection of your equipment Spectra Physics will only ship Spectra Physics equipment in original containers you will be charged for replacement con tainers if they are needed The OPA SOOC is shipped in one crate with two containers inside One con tainer is the OPA SOOC the other contains the accessory kit and any other options you may have ordered Chapter 1 contains a list of crystal options currently available You will find the following items packed in the accessory kit e This user s manual e The OPA SOOC crystals with holders e An accessory case containing the following tools e Allen hex wrench tool kit e Infrared detector card e Disposable hemostat e Tweezer e Lens tissue e Finger cots e 3 4 20 screws with washers e 5 6 3 cm alignment target ca
25. 800CF 0 3 is configured for a 5 kHz Spufire Hurricane or Spitfire Hurricane LCX Specifications apply to operation at the wavelength noted gt A Gaussian pulse shape is used to determine the pulse width from the autocorrelation function x 0 71 For the OPA SOOCF pumped by the Spitfire Hurricane USF Spitfire Hurricane SOFS the OPA 800CF output pulse width is lt 80 fs or lt 50 fs at the noted wavelength 9 pulse to pulse stability Table 3 2 OPA 800CP Specifications Pump Pulse Output Performance Requirement Signal Output A 1 3 um Idler Output A 2 08 um Pulse Energy 1 0 mJ 60 uy 25 uy 0 5 mJ 30 uJ 13 uJ Pulse Width 4 5 ps lt 1 5 ps lt 1 5 ps Line Width 22 cm lt 25 cm lt 25 cm Tuning Range 800 nm 5 nm 1 10 1 60 um 1 60 um 3 00 um Repetition Rate Nominal 1 kHz 1 kHz Energy Stability lt 3 lt 3 Polarization Horizontal Linear Vertical Due to our continuous improvement policy specifications are subject to change without notice and only apply when the OPA 800CP is pumped by a Spectra Physics Tsunami Millennia or BeamLok and Merlin Spitfire Hurricane system For 54 dual OPA system contact Spectra Physics 2 A I mJ pumped OPA 800CP 1 is normally configured for a standard 1 kHz Spitfire Hurricane 3 Specifications apply to operation at the wavelength noted A Gaussian pulse shape is used to determine the pulse width from the autocorrelation function x 0 71 gt pulse
26. 800nm Y Periscope G0382 016 x2 G0382 016 x2 1 lt gt Y Delay 2 0450 9840 i m ii e 0450 9850 la G0382 016 ay A La Power Amp E E Pre Amp A a 3828 0613 I 3827 1581 N dl i 3828 0634 Y V 3827 1643 3827 1581 I I l i E o 3827 1552 Gos82 016 N L 3827 1532 A ee 1 ie pe G0501 001 3827 1739 a a NA E gt 3 ue G0501 001 G0501 001 3827 1581 0454 0860 me gora Se G0502 001 3827 1581 pi Delay 1 A lt Q Wavelength Extension Option 3827 1739 v 9 puoi i Ys a al Y Y Residual Optional Signal Idler Optional Pump Pump for Pump for Second OPA Second OPA Figure 9 2 OPA 800CP Optics Part Numbers by Location G0020 031 G0382 016 G0382 016 3827 1520 3828 0635 3827 1581 Harmonic Output Chapter 10 Customer Service Warranty Customer Service At Spectra Physics we take pride in the durability of our products We place considerable emphasis on controlled manufacturing methods and quality control throughout the manufacturing process nevertheless even the finest precision instruments will need occasional service We feel our instruments have excellent service records compared to competitive prod ucts and we hope to demonstrate in the long run that we provide the best service to our customers not only in providing the best equipment for the money
27. AM INIA 1 1 Ap 1 Signal Idler SHG SHG FHG FHG DFM SFM P S SFM P l Signal Idler Signal Idler um um nm um nm nm um nm nm 1 000 4 263 500 0 2 13 250 0 1065 8 1 050 3 544 525 0 1 77 262 5 885 9 1 100 3 072 550 0 1 54 275 0 768 1 1 125 2 893 562 5 1 45 281 3 723 2 1 150 2 740 575 0 1 37 287 5 684 9 1 175 2 608 587 5 1 30 293 8 651 9 1 200 2 492 600 0 1 25 300 0 623 1 2 31 480 611 1 225 2 391 612 5 1 20 306 3 597 7 2 51 484 605 1 250 2 301 625 0 1 15 312 5 575 3 2 74 488 599 1 275 2 221 637 5 1 11 318 8 555 2 2 99 492 594 1 300 2 149 650 0 1 07 325 0 537 2 3 29 495 588 1 325 2 084 662 5 1 04 331 3 521 0 3 64 499 583 1 350 2 025 675 0 1 01 337 5 506 3 4 05 502 579 1 375 1 971 687 5 0 99 343 8 492 8 4 55 506 574 1 400 1 922 700 0 0 96 350 0 480 5 5 15 509 570 1 425 1 877 712 5 0 94 356 3 469 2 5 92 512 566 1 450 1 835 725 0 0 92 362 5 458 8 6 91 516 562 1 475 1 797 737 5 0 90 368 8 449 2 8 24 519 558 1 485 1 782 742 5 0 89 371 3 445 5 8 91 520 557 1 500 1 761 750 0 0 88 375 0 440 2 10 13 522 555 1 525 1 728 762 5 0 86 381 3 431 9 525 551 1 550 1 697 775 0 0 85 387 5 424 2 528 548 1 575 1 668 787 5 0 83 393 8 416 9 531 545 1 600 1 641 800 0 0 82 400 0 410 1 533 542 1 625 1 615 812 5 0 80 406 3 403 8 536 535 B 4 OPA 800C Wavelength Tables Table B 5 Corresponding OPA 800C Output Wavelengths for an 825 nm Pump Input Not for specified performance Ag i Asue AsHG FHG FHG ADEM AsFM AsFmM HAYA
28. Cases Grating Angle 1 order Idler seed 61 6 52 1 46 1 41 3 38 6 36 1 34 1 32 4 30 9 29 7 28 um Grating Angle Grating Angle s UM 2 order Signal Seed 1 Lorder Signal Seed 2 933 41 3 19 3 1 10 2 629 43 6 20 2 1 15 2 400 46 1 21 1 1 20 2 222 48 6 22 0 1 25 2 080 51 3 22 9 1 30 1 964 54 1 23 9 1 35 1 867 57 1 24 8 1 40 1 785 60 5 25 8 1 45 1 714 64 2 26 7 1 50 1 653 68 4 217 7 1 55 1 600 73 7 28 7 1 60 l Spectra Physics tested this system for operation from 1 1 to 1 6 using the first order idler seeding However for higher energy between 1 1 and 1 2 Um use the second order signal seed 6 6 A first order signal seeded OPA SOOCP outputs a slightly broader spectral bandwidth but a second order signal seeded OPA SOOCP produces an out put bandwidth that is as narrow as the idler seeded case but with higher output power between 1 1 and 1 2 nm The major operating difference between an OPA SOOCP and OPA SOOCF is the method of wavelength tuning OPA SOOCP wavelength tuning is accomplished by tuning both the grating angle and the BBO crystal instead of just the crystal In fact since the acceptance bandwidth of the BBO crys tal is much larger than the selected spectral bandwidth wavelength tuning is basically determined by the grating angle the BBO crystal angle only affects output energy Changing DELAY 2 will also tune the output wave length slightly Table 6 1 compares the first
29. H AR O AN E A LR e KR e T SS v7 amp Il E Ko TA SS RY S s O IN LX I t1 dd SFM Crystal 00 Figure 7 8 Mechanical Layout of the OPA 800CF Arranged for SFM 7 9 OPA 800C Ultrafast Optical Parametric Amplifier Three dichroic mirrors DDM _3 should be mounted in the same way they were for the HGII with 40 output refer to Figure 7 7 The SFM beam is directed out the SFM FHG exit port as shown in outline drawing Figure 3 13 The three dichroic mirrors cover the full SFM output range and give good spectral purity The mechanical optical layout is shown in Figure 7 8 The output sum frequency mixed beam is horizontally polarized for either the signal or idler mixed with the residual pump beam Difference Frequency Mixing Option DFM 7 10 The DFM option mixes the signal with the idler to extend the wavelength from 3 um to 10 um This is a very important frequency region for the study of molecular vibrational transitions The DFM signal within the 3 um to 10 um wavelength range can be effi ciently generated using a silver gallium sulfide AgGaS crystal Remove the PS from the beam and align the output signal and idler beams to prop agate along the central line of the option Verify the beams are 6 3 cm above the base plate Place a marker at the beam before the long pass filter and then place the fused silica lens Les into the beam at the position shown in Figure 7 9 so that the beam still remains on
30. OPA 800C Ultrafast Optical Parametric Amplifier User s Manual S Spectra Physics 1335 Terra Bella Avenue Mountain View CA 94043 Part Number 0000 277A Rev G November 2003 Preface This manual contains information about the installation alignment opera tion maintenance and service of your Spectra Physics OPA SOOC ultrafast optical parametric amplifier The introductory chapter contains a brief description of the OPA 800C and explains its role as part of the Spectra Physics ultrafast family of fs ps and fs ps products It is designed for use with the Spectra Physics Spitfire Hur ricane Ti sapphire regenerative amplifier pumped by the Merlin intracav ity doubled Nd YLF laser or Evolution diode pumped solid state laser and seeded with either the Tsunami fs ps mode locked Ti sapphire laser pumped by either a BeamLok argon ion or Millennia solid state laser or a Mai Tai fs ps mode locked Ti sapphire laser All these lasers are Class IV lasers and they as well as the OPA 800C emit laser radiation that can permanently damage eyes and skin The Laser Safety section contains information about these hazards and offers sug gestions on how to safeguard against them To minimize the risk of injury or expensive repairs be sure to read this chapter and carefully follow these instructions OPA Description contains a discussion of optical parametric amplifica tion and provides a more detailed descripti
31. OPA 800CP Symptom Low OPA output signal idler Possible Causes Corrective Action BBO angle is incorrect Grating angle is incorrect OPA seed wavelength is incorrect Delays are not optimized Pre amplifier beam does not overlap with the white light Pre amplifier and or power amplifier pump beam focusing are not optimized Pump pulse duration is too long Pump beam mode is bad OPA pump beam has moved Pump beam spectrum is too narrow Set the BBO angle for the desired wavelength Set the grating angle for a wavelength that corresponds to the BBO phase matching wavelength see Figure 6 3 and 6 4 Check Table 6 1 for the grating angle setting for the idler seed You can use the second order diffracted signal beam to seed at A lt 1 25 um Optimize both DELAY 1 and 2 for power Steer the D mirror for higher power Adjust the focusing of the white light by translating CL Adjust L and or L for higher power One indication of the proper focusing is that the amount of OPG should be 10 25 uJ for a 1 mJ pumped OPA 800P when the WL seed is blocked Optimize the compressor grating separation in the Spitfire or Hurricane with the remote controller Aperture the amplifier output beam by using apertures in the regenerative amplifier cavity Optimize the green pump beam to the regenerative amplifier Steer periscope PS slightly to correct it Check the alignment of each arm in the OPA Ver
32. PA 800C Ultrafast Optical Parametric Amplifier Tuning Curves 140 S 120 gt D 100 c Lu T 80 A 5 Q 60 D O 40 20 0 1 0 1 2 1 4 1 6 1 8 2 0 2 2 2 4 2 6 2 8 3 0 Wavelength um Figure 3 5 Typical Output Tuning Curves of an OPA 800CF 1 Output Pulse Energy uJ 1 0 1 2 1 4 1 6 1 8 2 0 2 2 2 4 2 6 2 8 3 0 Wavelength um Figure 3 6 Typical Output Tuning Curves of an OPA 800CP 1 3 8 Description Second Harmonic Option 10 Fourth Harmonic Option 40 e Ba 30 Y ye Pusle Energy uJ NO 5 Pusle Energy uJ 0 60 0 70 0 80 0 90 1 00 1 10 1 20 300 350 400 450 500 550 600 Wavelength um Wavelength nm Sum Frequency Mixing Option Difference Frequency Mixing Option 80 12 Op Os E 3 60 3 a P gt D i p z D a Op Oj D ij 40 Lu e a 02 m A 4 A 0 A 480 500 520 540 560 580 600 2 4 6 8 10 Wavelength nm Wavelength um Figure 3 7 Typical Output Tuning Curves for Wavelength Extensions for an OPA 800CF 1 OPA 800C Ultrafast Optical Parametric Amplifier Second Harmonic Option Fourth Harmonic Option Pusle Energy uJ Pusle Energy uJ 600 800 1000 1200 300 400 500 600 Wavelength nm Wavelength nm Sum Frequency Mixing Option Difference Frequency Mixing Option 6 ee y BP gt gt 4 D D 3 i i Os Oi o 2 a 02 D gt A a 1 0 480 500 520 540 560 580 600 2 4 6 8 10 Wavelength nm Wavelen
33. Refer to Chapter 4 Adjust DELAY 2 for best SFM output Align the pre amplifier WL and the power pump beam for overlapped output as measured in front of SFM Remove Lgr and Les for 2 4 and perhaps 24 and 44 Do not use polarizer P for 4 26 or 44 Optimize OPA output energy for best beam quality Symptom Low or bad output with the DFM option installed Possible Causes Corrective Action Lenses are not installed The signal and idler beams are not properly aligned Poor crystal orientation Install the lenses Center both with the signal and idler beams Verify the signal and idler beams are collinear and tempo raly synchronized Verify the DFM crystal is oriented correctly Symptom Incorrect spectra of signal idler or their harmonics Possible Causes Corrective Action Incorrect temporal overlap Misaligned pump beams Misaligned crystals Optimize DELAY 1 and DELAY 2 while checking the spectrum Verify the pre and power pump beams are parallel to the base plate and collinear with WL Optimize the OPA and the harmonic crystals for the best spectral shape Part Il OPA 800CP Symptom No white light Service and Repair Possible Causes Corrective Action The pump pulse duration is incorrect The pump pulse energy is too low The pump beam spatial mode is bad The white light plate is not at the right position Check the pulse duration and make sure i
34. and fourth har monic of the idler and the second harmonic of the signal The wavelength coverage is 800 1200 nm for the second harmonic of the idler 400 600 nm for the fourth harmonic of the idler and 600 800 nm for the sec ond harmonic of the signal Figure 7 1 Figure 7 2 and Figure 7 3 show the mechanical layouts for these configurations 7 1 OPA 800C Ultrafast Optical Parametric Amplifier oll rs ah Figure 7 1 Mechanical Layout of the OPA 800CF Arranged for SHG of the Idler 7 2 OPA 800C Options AN Sd n no BANT sali EES ESA 7 o AM Tiel ogg o or ao H E W wW OS LE Pr 8 E SS ING SIS 8 TAR XX Z O am an E gt E Z V NOG Y POS A 1 LA A Y e adl AE mms A Le E alle Cle Hy Ba ZO N 7 E 7 3 Figure 7 2 Mechanical Layout of the OPA 800CF Arranged for FHG of the Idler OPA 800C Ultrafast Optical Parametric Amplifier SY Te TL Kod Nx O O A HANS YS O o P S O a L a aa o SUE O Q Eo i me a b NI m o i Figure 7 3 Mechanical Layout of the OPA 800CF Arranged for SHG of the Signal 7 4 OPA 800C Options For the second harmonic generation SHG of the idler periscope PS sepa rates the idler beam from the signal A BaF lens Lg is also mounted on the hole in front of PS as shown in Figure 7 1 and a BBO type I crystal i
35. ange the L and L mounts for fs operation In order to easily access the adjustment screw of L you can assemble the top portion of the translation stage so that it is rotated 180 from that shown in Figure 4 4 9 Replace the ps OPA BBO crystal with the 3 mm fs OPA crystal The crystal holder comprises three parts that are clamped together in the mount by a spring loaded mechanism which is part of the holder When the holder is removed from the mount the spring is released and these three parts will fall apart unless held together If they fall apart reassemble them as shown in Figure 4 5 Figure 4 4 L L Placement for ps and fs Configurations Clamping screw Top holder 2 piece spring loaded El Yoke opening xa Inner side i Yoke and crystal El Yoke opening Bottom holder ps Crystal with Holder fs Crystal with Holder Figure 4 5 The ps and fs crystals with holders 4 9 OPA 800C Ultrafast Optical Parametric Amplifier a Remove the crystal holder from the mount by turning the clamping screw on the top holder clockwise to compress the spring mecha nism then carefully slide the holder out of the mount Place some lens tissue under the crystal mount to prevent the crys tal from directly falling onto the base plate if 1t becomes loose b Assemble the fs 3 piece crystal holder and carefully slide it into place in the mount Note which side of the yoke is the inner side that goes next to the mount Do no
36. angle the signal wavelength becomes longer and the idler wavelength becomes shorter For example if the BBO crystal is mounted in the recommended manner 1 e the pre pump beam is reflected downward from the BBO crystal the smaller the BBO crystal micrometer reading the shorter the signal wave length Figure 6 3 In the idler seeded case increasing the grating angle requires you to decrease the BBO micrometer reading in order to get good output energy This ensures that the OPA SOOCP is idler seeded Figure 6 4 shows a typical wavelength vs grating angle micrometer readout for a first order diffracted idler seeded case Both curves assume that the crystal and grating are mounted correctly and that the pump wavelength is 800 nm and the WL is parallel to the base plate between the BBO crystal and the grat ing An idler seeded ps OPA 800CP gives best performance and continuous wavelength tuning from 1 1 to 3 0 um When the signal wavelength is below 1 2 um the output energy might decrease significantly because of absorption of the idler and smaller gain Focusing both pump beams slightly tighter will help get higher output between 1 1 and 1 2 um 35 30 25 20 Grating Angle Micrometer Position mm 1 1 12 1 3 1 4 1 5 1 6 Signal Wavelength um Figure 6 4 Typical Signal Wavelength vs Grating Angle Position 6 5 OPA 800C Ultrafast Optical Parametric Amplifier Table 6 1 600 g mm Grating Angles for Idler or Signal Seeded
37. anted for 90 days Liability under this warranty is limited to repairing replacing or giving credit for the purchase price of any equipment that proves defective during the warranty period provided prior authorization for such return has been given by an authorized representative of Spectra Physics Warranty repairs 10 1 OPA 800C Ultrafast Optical Parametric Amplifier or replacement equipment is warranted only for the remaining unexpired portion of the original warranty period applicable to the repaired or replaced equipment This warranty does not apply to any instrument or component not manufac tured by Spectra Physics When products manufactured by others are included in Spectra Physics equipment the original manufacturer s war ranty is extended to Spectra Physics customers When products manufac tured by others are used in conjunction with Spectra Physics equipment this warranty is extended only to the equipment manufactured by Spectra Physics This warranty also does not apply to equipment or components that upon inspection by Spectra Physics discloses to be defective or unworkable due to abuse mishandling misuse alteration negligence improper installa tion unauthorized modification damage in transit or other causes beyond the control of Spectra Physics Spectra Physics will provide at its expense all parts and labor and one way return shipping of the defective part or instrument if required This warranty is i
38. ass IVW High Power Lasers and Accessories 2 1 Maintenance Required to Keep this Laser Product in Compliance with the Center for Devices and Radiological Health CDRH Regulations 0 0 0c eee 2 3 CDRH CE Dia Wine 16 ninapenda Sead Ke bea aed at eed batho teetaaeemaeehaidtecue es 2 4 kabel Translations dis Thee Actas ida a SR BORN Aia 2 5 GE Declaralion ol COnionnity rad te aa a eee teehee Velen a ead 2 6 Sources for Additional Information ssassn aaia ea a eee eee eas 2 7 Laser Safety Standards x seria tata ea ass Sve ee nan oe Se oe hae AAA AA 2 7 Equibmentana Training 47525 3 het E a ee ee ee ER ee Ree a ee he 2 8 Chapter 3 Description si cs eterna a ia ee well wee Bae ed 3 1 NRO CUCL OM 5 229 ty A ER O 3 1 MLO OU sucia aa 3 1 OPA 300G SYSlEMS scan pes 8 vid BO ta hs oe eRe S608 Seb Skee ee eee 3 5 TUNG HS CIVICS 52s Artec ate a ee E wan osc opts es O abe eRe ae 3 8 OPC CM AU ON piso arte ce ie eee Bet whee tend tog an S eel cee a pan Bok a be tasa 3 11 Mechanical Optical Configurations for the OPA 800C 0 ee ee 3 12 SPSCINC AL OMS te ws wae a dco nec ah ad BSS GRE trobar a ad 3 16 ORD WINS sor oa heres iiss Ad ai 3 18 OPA 800C Ultrafast Optical Parametric Amplifier Chapter 4 OPA 800CF Installation and Alignment 0 o o 4 1 Required EQUIDIMENE e exista dad tia ae ee er Eo 4 1 A A O O 4 1 ASTalatON erat ca dr le ad ad a ere et aaa 4 3 AITANA a a an a is Dt wt eee ete ee Oe 4 4 Whi
39. ast Optical Parametric Amplifier the bandwidth of the signal and idler pulses are relatively independent of the phase matching conditions In fact for a type II process it 1s possible to tune right through the degeneracy point without obtaining pulses with abnormally large bandwidth The signal and idler waves actually undergo a polarization flip at the degeneracy point This is sometimes referred to as type IIb phase matching The OPA 800C can be pumped with any output wavelength from the Spit fire Hurricane amplifier which is tunable from 750 to 840 nm However the performance specifications are based upon pump energies up to 1 mJ pulse widths of lt 130 lt 80 and lt 50 fs at 800 nm for an OPA SOOCF and a 1 mJ gt 1 ps pulse width at 800 nm for an OPA SOOCP Figure 3 5 and Fig ure 3 6 show typical tuning curves for 1 mJ pump conditions The signal and idler outputs provide pulses with up to 80 uJ of energy with broad wavelength coverage from 1 1 um to 3 0 um Refer to Table 3 1 and Table 3 2 at the end of this chapter 5 x 10 Foot Table Millennia S Merlin OPA 800C b A Typical Hurricane and OPA 800C System Layout with optional second OPA Figure 3 3 Typical OPA 800C System Layouts Description Signal and Idler Wavelength um Phase matching Angle Phase matching Angle a Type Phase Match b Type Il Phase Match Figure 3 4 Wavelength vs Phase Matching Angle of Type I and Type II Crystals 3 7 O
40. at each crystal is properly oriented Verify that the harmonic crystals are optimized for the best spectral shape Purge the OPA to eliminate water absorption Symptom Bad output beam quality Possible Causes Corrective Action Bad OPA pump beam Pre amplifier or power amplifier pump beam size is too big or too small Damaged optics Damaged BBO crystal Conversion efficiency is too high Optimize output amplifier beam quality Optimize the power amplifier pump beam size at the BBO crys tal Replace the damaged optics check Rs and OR to see any damages Replace the damaged crystal or shift the crystal to a good spot Reduce the focusing of both pump beams by adjusting L and L OPA 800C Ultrafast Optical Parametric Amplifier Symptom OPA output at OR has three separate spots not in a vertical line Possible Causes Corrective Action DELAY 2 is not optimized Optimize DELAY 2 Grating groove orientation is incorrect Rotate the grating so the diffracted beam is vertical Grating rotational axis is off Remount the whole mount onto the translation stage so the dif fracted beam reflects back to the BBO crystal and does not move while changing the angle of the grating see Chapter 5 Power amplifier pump beam is not col Steer R and D to make sure they are collinear When this is linear with the white light the case three spots are visible in a single vertical line when DELAY 2 synchron
41. at these pump wave lengths Table B 1 Corresponding OPA 800C Output Wavelengths for an 800 nm Pump Input s i AsHG AsHG AFHG FHG ADEM AsFM AsFM IN A2 r 2 AJA MA ANAND AN AMAN tA I Signal Idler SHG SHG FHG FHG DFM SFM P S SFM P Signal Idler Signal Idler um um nm m nm nm um nm nm 1 090 3 007 1 100 2 933 1 125 2 69 1 150 2 629 1 175 2 507 1 200 2 400 600 0 1 20 300 0 600 0 480 600 1 225 2 306 612 5 1 15 306 3 576 5 484 594 1 250 2 222 625 0 1 11 312 5 555 6 2 86 488 588 1 275 2 147 637 5 1 07 318 8 536 8 3 14 492 583 1 300 2 080 650 0 1 04 325 0 520 0 3 47 495 578 1 325 2 019 662 5 1 01 331 3 504 8 3 85 499 573 1 350 1 964 675 0 0 98 337 5 490 9 4 32 502 568 1 375 1 913 687 5 0 96 343 8 478 3 4 89 506 564 1 400 1 867 700 0 0 93 350 0 466 7 5 60 509 560 1 425 1 824 712 5 0 91 356 3 456 0 6 51 512 556 1 450 1 785 725 0 0 89 362 5 446 2 7 73 516 552 1 475 1 748 737 5 0 87 368 8 437 0 9 44 519 549 1 485 1 734 742 5 0 87 371 3 433 6 10 33 520 547 1 500 1 714 750 0 0 86 375 0 428 6 522 545 1 525 1 683 762 5 0 84 381 3 420 7 525 542 1 550 1 653 775 0 0 83 387 5 413 3 528 539 1 575 1 626 787 5 0 81 393 8 406 5 531 536 1 600 1 600 800 0 0 80 400 0 400 0 533 533 B 1 OPA 800C Ultrafast Optical Parametric Amplifier Table B 2 Corresponding OPA 800C Output Wavelengths for a 780 nm Pump Input Not for specified performance Ag i AsHG AsHG FHG FHG ADEM AsFm AsFM WAN 1
42. bers by Location 0 0 00 c eee eee 9 10 Figure 9 2 OPA 800CP Optics Part Numbers by Location 0 0 0 0 ccc cece ee 9 12 Figure A 1 Schematic of a Stretcher with ps Mask 0 0 00 0 cece eens A 1 Figure A 2 Standard Symmetrical Grating Configuration 0 00 cc ees A 2 Figure A 3 Grating Configuration Modified for ps masked Spitfire o ooooooooo A 3 List of Tables Table 21 s Label TransiatoAS 2 a a eee bee eee ae 2 5 Table 3 1 OPA 800CF Specifications 0 0 ee eee eens 3 16 Table 3 2 OPA 800CP Specifications 0 0 0 0 eee ee eens 3 16 Table 3 3 Specifications of OPA 800CF Wavelength Extension Options eetere mies Table 3 4 Specifications of OPA 800CP Wavelength Extension Options ceecee ereenn Pa Table 6 1 600 g mm Grating Angles for Idler or Signal Seeded Cases naana anaana 6 6 Table 7 1 Output beam polarization from OPA 800C o ooocococonono ee 7 12 Table A 1 Spectral bandwidth at 800 nm vs the width of the mask slit for a ps masked Spitfire A 2 Table A 2 Corresponding bandwidth in nm of 25 cm spectrum at different wavelengths A 4 Table B 1 Corresponding OPA 800C Output Wavelengths for an 800 nm Pump Input B 1 Table B 2 Corresponding OPA 800C Output Wavelengths for a 780 nm Pump Input Not for specified performance 1 2 0 cc eee ee eee eens B 2 Table B 3 Corresponding OPA 800C Output Wavelengths for a 790 n
43. c amplifier is designed to deliver high energy near transform limited ps pulses with wavelengths ranging from lt 300 nm to gt 10 um The optics layout is very similar to that in the fs OPA SOOCF and this ps unit can be easily converted to a fs unit and vice versa This chapter will guide you through the installa tion and alignment of your OPA SOOCP If you are operating a fs system please refer to Chapter 4 Refer to Figure 5 1 while performing the following procedures Safety eyewear should be worn throughout this procedure Refer to your Spitfire Hurricane manual for proper installation of the amplifier system Proper installation is essential for optimal OPA SOOCP performance If you have a fs ps OPA SOOCFP we recommend you first align your sys tem and get it running as a fs OPA before aligning it as a ps unit Chapter 4 contains the fs alignment procedure If you have a fs only OPA SOOCF ignore this chapter Required Equipment Precautions The following equipment will help you properly align your ps OPA e Laser goggles that protect against laser wavelengths from 200 nm to gt 10 um e Infrared card e Spectrometer e Power meter e Two 6 3 cm height alignment targets provided in this manual e Ir detector and fast oscilloscope e Do not use the output of a ps Spitfire Hurricane amplifier to pump an OPA SOOCFP configured for fs operation A fs ps unit may be shipped as a fs configuration 5 1 OPA 800C Ultrafa
44. components in this three wave process given by P Q 2e 9d El E 2a P 2 0d Ela E 2b P 2 gd Ela E 2c where it is assumed gt gt Q Using slowly varying amplitude approximations neglecting loss and assuming steady state solutions Equation 1 becomes three coupled travel ing wave equations dE dz 1KE E exp 1Ak z 3a dE dz 1KE E exp 1Ak z 3b dEz dz 1KE E exp 1Ak z 3c where K l nc and d is the nonlinear polarization coefficient E a is now written as E exp ik z and Ak k k k where 1 is 1 2 or 3 These three equations describe the basic physics of second harmonic gener ation sum frequency and difference frequency mixings and parametric generation in the afore mentioned approximation with appropriate bound Description ary conditions The general solutions to these equations indicate that high efficient conversion from one wave to another requires a high pump intensity wave or waves b high nonlinear polarization coefficient d and c a better phase match e g a smaller Ak for continuous waves cw To have a high conversion efficiency of the three wave process a high sec ond order nonlinear susceptibility of the nonlinear medium is desirable In the OPA process shown in Figure 3 1a a high intensity pump beam is used to amplify a low energy seed beam as shown in Figure 3 2 Either the sig nal or idler beam pulses can be used as the seed s
45. cs A white card cut to 1 2 x 10 cm may reduce the chance of this happening l oH Block the two beams in front of T and T with white cards De focus the pre amplifier beam by translating L closer to L Warning W Too small of a beam will damage the BBO crystal 2 4 10 11 12 13 Adjust BS so that the pre amplifier beam and the WL beam are over lapped right after D4 Adjust D so that the pre amplifier pump beam and the WL are over lapped before WLR Iterate Steps 3 and 4 until the two beams are well overlapped Block the WL before CL with a business card Set the BBO crystal at the angle corresponding to A 1 3 um accord ing to the setting on the OPA SOOCP Final Test Performance Summary Sheet shipped with this OPA SOOCP or see Figure 6 3 To prevent damage to Rs place a card in front of D With the room lights off and and fully open gradually focus the pre amplifier beam by translating L until some superfluorescence optical parametric generation or OPG light above and below the beam appears on the card in front of D The pre amplification pump beam should be focused about 6 cm after the BBO crystal or 6 cm before D Remove the card from in front of CL Translate DELAY 1 back and forth until the WL beam gets amplified and becomes brighter or increases slightly in size Remove the card from in front of D Optimize DELAY 1 for best WL amplification as determined by using a photodiode
46. d Pre amplifier pump beam intensity is too low Beams are poorly temporally overlapped BBO angle is incorrect Overlap the white light with the pre amplifier pump beam from D to after Dp Tighten its focusing to generate some OPG by moving L Change DELAY 1 and search for amplification using ir detec tors Verify the CL stage does not interfere with the movement of DELAY 1 Verify WLP is not mounted in the farthest position from FL Set the BBO angle for roughly the desired wavelength and within the specified range OPA 800C Ultrafast Optical Parametric Amplifier Symptom No power amplifier amplification Possible Causes Corrective Action BBO angle is incorrect Grating angle is incorrect Spatial overlap is incorrect Power amplifier pump beam intensity is low Not temporally overlapped Lens L Set the BBO angle for the desired wavelength Set the grating angle for a wavelength that corresponds to the BBO phase matching angle see Figure 6 3 and 6 4 Swing the grating angle around the setting while changing DELAY 2 Make sure the power amplifier pump beam is parallel to the OPA base plate and overlap with the diffracted seed beam Carefully tighten its focusing to generate some OPG at OR by slightly moving L Change DELAY 2 to search for amplification L stage should not interfere with DELAY 2 Otherwise properly install L bracket Make sure L is a 50 mm fl lens for an
47. d in front of D and adjust D so that the pre amplifier beam and the WL beam are overlapped before WLR 5 Iterate Steps 3 and 4 until the two beams are well overlapped 6 Use a business card to block the WL beam before CL 7 Set the BBO crystal at the angle corresponding to 4 1 3 um accord ing to the setting on the OPA SOOCF Final Test Performance Summary sheet shipped with this OPA SOOCF 8 To prevent damage to R place a card in front of D 9 Turn off the room lights and completely open and lp then gradually reduce the spot size of the pre amplifier beam by translating L until the pre amplification pump beam is focused about 4 cm 1 cm in front of D and 8 cm 1 cm after the BBO crystal a business card will eas ily burn at these points A small amount of superfluorescent optical parametric generation OPG light might appear in front of WLR above and below the pre amplifier beam 10 11 12 OPA 800CF Installation and Alignment Remove the cards from in front of D and CL Translate DELAY 1 back and forth until the WL beam gets amplified and becomes brighter Optimize DELAY 1 for best WL amplification as determined by moni toring the amplified beam with a photodiode or power meter Note To help find the WL amplification use a fast oscilloscope with an infra red photodetector placed in front of a card located in front of WLR3 If this is not possible turn off the room lights and watch closely to see t
48. e rotation mount accordingly You can also rotate both grating mounts rela tive to the mounting plate Figure A 2 shows a standard symmetrical grat ing configuration and the proper position of the compression grating Mounting Plate Figure A 2 Standard Symmetrical Grating Configuration Figure A 3 shows an alternative mounting of these two gratings in case there are difficulties upgrading in the field Pumping an OPA 800CP with Spitfire Mounting Plate Figure A 3 Grating Configuration Modified for ps masked Spitfire As 1n the fs OPA the beam profile leaving the Spitfire directly affects the ps OPA efficiency and output beam quality Set the ps masked Spitfire for the best performance before starting the ps OPA alignment In general after setting up the Spitfire as outlined above the output should be 1 mJ per pulse lt 22 cm in spectral bandwidth and lt 1 6 ps in duration The compressed pulse duration should be very close to the transform limit A square shaped spectrum pulse has a Sinc function or a diffraction func tion temporal shape assuming it is transform limited The time bandwidth product of a transform limited square spectrum pulse iS AVT 0 8859 The ratio of pulse width and autocorrelation width for a square spectrum transform limited pulse 1s T T 0751 Spectrum bandwidth is often measured in spectroscopy as the width of a or as wavenumbers in cm A a x E For
49. e match 1 e 3 3 OPA 800C Ultrafast Optical Parametric Amplifier Ak k k k 0 7 or wavelength n A n A D A 8 where n 18 the refractive index of the nonlinear crystal at each wave length The latter requirement which is the equivalent of momentum conserva tion shows the need for a constructional accumulation of the generated new wavelengths while they travel together in the crystal Equations 6 and 8 determine the two down converted wavelengths By tuning the crystal angle which changes n n and n the two newly created wavelengths are tuned accordingly Since most OPAs are used with fs and ps lasers group velocity walk off between pulses also needs to be accounted for in order to achieve best con version This becomes even more important when extremely short pump pulses are used For efficient energy exchange the interaction length should be as long as possible without limiting the acceptance bandwidth This is governed by the temporal walk off of the pump and signal pulses after passing through a crystal of length L or their group velocity mismatch GVM where T and T are the group delay times of the pump and signal respectively When considering GVM the amplified Ti sapphire funda mental is the preferred pump wavelength Another benefit of using the fun damental pump frequency is that the signal and idler beams can be conveniently difference frequency mixed to produce the importa
50. e this signal to seed the OPA SOOCP If you have difficulty generating white light check the bandwidth and or the pulse duration of the Spitfire Hurricane output to see whether it meets the requirements for pumping the OPA SOOCP If the WL beam has a small bright spot that moves around or is not cen trally located try reducing the pump beam energy by carefully rotating the WP Look into the WLP from the exit side at a 20 to 30 angle and move the FL lens so that the WL filament gradually diminishes before the end of the plate If this is not possible translate the plate and adjust the pulse energy using the WP while looking for a stable WL The WL filament should appear wedged and relatively centered in the WLP Figure 5 3 If the WL filament appears to impinge the face the OPA 800CP will be less stable and damage may occur to the WLP within hours Make sure the WL filament diminishes before the end of the plate OPA 800CP Installation and Alignment WLP lt White light filament properly centered WLP _ White light filament improperly centered Figure 5 3 White light filament as seen in the white light plate 9 10 11 12 13 Position CL so that it is centered in the beam If necessary adjust WLR so that the WL passes through D on the side closest to Lo Adjust WLR so that the WL passes through the BBO crystal on the inner side and hits WLR Refer to Figure 5 4 Steer WLR so that
51. e wide spectral coverage and easy wavelength tuning from deep UV lt 300 nm to mid IR gt 10 um with high energy pulses For convenience they install inside the OPA 800C chassis To use these options you do not need to change anything on the basic OPA SOOC except for tuning to the desired wavelength and adjusting the delays for optimum output When operating your OPA SOOCF at a signal wave length in the lt 1 15 um range better output power and stability is obtained by removing the D dichroic mirror and using the signal beam to seed the system The OPA SOOCP harmonic generation HGI and HGII sum frequency mixing SFM and difference frequency mixing DFM options are similar to those used for the OPA SOOCF The only difference is that ps crystals are longer than fs crystals Both systems have similar setup procedures When the SFM option is used the D dichroic mirror a flip mirror mount is placed in its down position out of the beam path and the residual pump beam propagates to the proper crystal and is mixed with either the signal or idler beam depending on which type of nonlinear crystal is in use The crystal thicknesses mentioned below for the various wavelength exten sion options are for the standard 130 fs or 80 fs OPA SOOCF and 1 5 ps OPA SOOCP systems Please note that thinner crystals are employed in the sub 50 fs OPA SOOCF Harmonic Generator Option HGI Harmonic option HGI allows you to generate the second
52. ean the crystals in the OPA BBO AgGaS Most are made of hygroscopic materials You can use Xylene to clean BBO if it is very necessary Do not use methanol or acetone h Caution ll Installation l OPA 800CP Installation and Alignment Close l and l when aligning the white light generator Always align the beam to hit the center of most optics except where noted Keep the beam height 6 3 cm above the base plate after PS and before PS Use one of the alignment cards provided in this manual For dual OPA operation or when splitting the pump beam for other pur poses make sure the transmitted part of the pump beam through PS is centered on the optional pump beam exit port and block 1t temporarily while you align this OPA Close all the irises in the OPA SOOCP and block the Spitfire Hurricane amplifier pump beam in front of periscope PS4 5 x 10 Foot Table Millennia S Merlin Tsunami Spitfire Ore Figure 5 2 Typical OPA 800CP Table Layout with optional second OPA 2 Verify the Spitfire Hurricane output beam is 15 9 0 3 cm above and parallel to the optical table and that the beam is directed toward the OPA SOOCP Orient the OPA SOOCP so that the Spitfire Hurricane output beam is perpendicular to the input side panel Figure 5 2 and hits the center of the input port Block the white light WL generation pump beam by placing a white card in front of WLP Remove the window plug and let the pump beam
53. ens Opt PLN CNX L 3827 1651 Lens Opt PLN CNX La 3827 1535 Lens Opt PLN CVX CL 3827 1534 Lens Opt PLN CVX FL 3827 1643 Long pass Filter DFM 2702 0271 Mirror Opt 25 4D x 6 Plano Silver Mirror 3827 1581 Mirror Opt 1 in x 0 25 tk Plano Gold Mirror 3827 1739 Mirror Opt PLN CCV 1 0D x 50Rd WLR 3827 1537 Polarizer Thin film P 0450 9780 Reflector 720 860 nm R Ro R3 G0382 016 W P 1 2 0 Ord Retarder WP 3827 1520 Window Opt 0 50 DX 0 12T Plane Sap SPL 3825 0092 For OPA SOOCUSF and its options OPA 800C Ultrafast Optical Parametric Amplifier Replacement Parts Diagram OPA 800CF Input Alternative Input 800nm 800nm Y Periscope G0382 016 x2 G0382 016 x2 G0020 032 G0382 016 lt gt Delay 2 0450 9840 pS e M n is 0450 9850 A hi G0382 016 WMO Y 4 ay m _ _ lt gt L4 3827 1651 3825 0092 3827 1581 3827 1537 1581 G0382 016 AIL 3827 1532 bee G0501 001 3827 1739 G0502 001 C D uN G0501 001 G0501 001 pet too 3827 1 581 0453 6020 3827 1581 A G0502 001 3827 1581 E E a Delay 1 A i a 3 a Wavelength Extension pian Pou l UIM greg a ee AS GS a Y y Residual Optional Signal Idler Optional Pump Pump for Pump for Second OPA Second OPA Figure 9 1 OPA 800CF Optics Part Numbers by Location Replacement Parts OPA 800CP Service and Repair Description Designation Part N
54. esult in hazardous radiation exposure Follow the instructions contained in this manual the Tsunami User s Man ual the Millennia User s Manual the Spitfire or Hurricane User s Manual the Merlin User s Manual the Evolution User s Manual and the BeamLok ion pump laser user s manual for safe operation of the OPA 800C system At all times during operation maintenance or service of your OPA 800C avoid unnecessary exposure to laser or collateral radiation that exceeds the accessible emission limits listed in Performance Standards for Laser Prod ucts United States Code of Federal Regulations 21CFR1040 10 d Any electronic product radiation except laser radiation emitted by a laser product as a result of or necessary for the operation of a laser incorporated into that product Danger Laser Radiation Danger Y Laser Safety Operating the OPA 800C the Spitfire or Hurricane amplifier or the Tsunami laser with the cover removed may expose people to high volt ages and high levels of infrared and visible radiation It also increases the rate of optical surface contamination and defeats the purpose of the purgeable sealed cavity For these reasons operating the system with these covers removed is not recommended The alignment procedures in this manual require internal adjustments while the laser beam is present always use appropriate safety glasses while making these adjustments Also when the cover is remo
55. for Measurement Control and Laboratory Use EN 60825 1 1993 Safety for Laser Products I the undersigned hereby declare that the equipment specified above con forms to the above Directives and Standards m7 Steve Sheng Vice President and General Manager Spectra Physics Inc Industrial and Scientific Lasers July 1 1999 Laser Safety Sources for Additional Information The following are some sources for additional information on laser safety standards safety equipment and training Laser Safety Standards Safe Use of Lasers Z136 1 1993 American National Standards Institute ANSI 11 West 42 Street New York NY 10036 Tel 212 642 4900 Occupational Safety and Health Administration Publication 8 1 7 U S Department of Labor 200 Constitution Avenue N W Room N3647 Washington DC 20210 Tel 202 693 1999 A Guide for Control of Laser Hazards 4th Edition Publication 0165 American Conference of Governmental and Industrial Hygienists ACGIH 1330 Kemper Meadow Drive Cincinnati OH 45240 Tel 513 742 2020 Internet www acgih org home htm Laser Institute of America 13501 Ingenuity Drive Suite 128 Orlando FL 32826 Tel 800 345 2737 Internet www laserinstitute org Compliance Engineering 70 Codman Hill Road Boxborough MA 01719 Tel 978 635 8580 International Electrotechnical Commission Journal of the European Communities EN60825 1 TR3 Ed 1 0 Laser Safety Measurement and I
56. for final amplifi cation R and R are mounted on delay translation stage DELAY 2 to tempo rally overlap the power pump beam with the pre amplified white light returning from WLR The amplified signal and idler output wavelengths are determined by the phase matching angle of the BBO crystal For fs systems wavelength tun ing is accomplished by changing the BBO phase matching angle and adjusting each delay stage for optimum output energy For ps systems the grating angle is also changed The residual 800 nm beam is separated from the amplified signal and idler beams by dichroic mirror D and the signal and idler are then either sepa rated and made available through different exit ports or are sent to the har monic generation leg for wavelength extension through second and fourth harmonic generation Mechanical Optical Configurations for the OPA 800C The following pages show the mechanical optical layouts for the fs ps and fs ps versions For all other options the mechanical optical layouts are shown in Chapter 7 Description Ye O SS O RS IL O Y O S gt X o O O D K y O O g MAM O O O O Tose Ml ta it O i O O O O O AN O BR O E o Q K Figure 3 10 Mechanical Layout of the OPA 800CF OPA 800C Ultrafast Optical Parametric Amplifier Description SA gx o A KY na ION al Ep j ZX H o Oe 1 4 IO O gr a 7 Os r a By O Z X AN O o O K gt H g S a e
57. g Raman shifting multi photon processes etc Since the white light generation seed 1s gener ated separately and is set for the whole tuning range the OPA output becomes easier to align and has a stable output over a much wider tuning range For both fs and ps pulses white light can easily be created by focusing a few uJ of energy into a variety of materials such as quartz sapphire or a liquid cell Thus the broad spectral coverage of the white light continuum provides an ideal seed source for an OPA Furthermore this same seed source can be employed for multiple OPAs each of which can provide independently tunable pulses for different spectroscopic applications In the ps regime white light can be generated either through liquids or through solid state materials In many laboratories the circulating liquid cell has been used However stable consistent white light generation through flowing liquids is a challenge in practice and not very convenient because the liquids have to be changed from time to time and some of them are toxic Thus a solid state material is preferable The white light can be saturatedly generated within The OPA SOOCFP uses solid state materials for white light generation This allows the user to conveniently select wavelength content because it provides a means to easily convert the OPA from a ps application to one in the fs domain and vice versa OPA 800C Systems Typical layouts for the Spectra Physic
58. gainst laser wavelengths from 200 nm to gt 10 um Infrared card Spectrometer Power meter Two 6 3 cm height alignment targets provided in this manual Ir detector and fast oscilloscope Precautions e Do not use the output of a fs Spitfire Hurricane amplifier to pump an OPA SOOCFP that is configured for ps operation An OPA SOOCFP may be shipped as a ps configuration e This OPA SOOCF can be pumped by the output of the Spitfire Hurri cane amplifier with 1 mJ 0 75 mJ 0 5 mJ or possibly 0 3 mJ per pulse with a pulse duration of less than 130 fs at the center wavelength of 800 nm The Spitfire Hurricane output spatial mode quality is criti cal for high OPA conversion efficiency 4 1 OPA 800C Ultrafast Optical Parametric Amplifier Input Alternative Input 800nm 800nm Y Periscope PS4 Periscope 1 PS4 BS Ry A Y E 2 1 ae ay BS yin E Power Amp l Ro White Light Generator A l C gt Wavelength Extension Option i OR Y 0 A Y Residual Optional Signal Idler Optional Pump Pump for Pump for Second OPA Second OPA BS 2 Beam Splitter 4 0 Irises Ro 5 Reflectors for 800 nm CL Collimating Lens L4a Lenses T4 2 Telescopes D 4 Dichroic Mirrors OR1 3 Output Reflectors WLP White light Plate FL Focusing Lens P Thin film Polarizer WLRy_4 White light Reflectors PS1 2 Periscope WP M2 Waveplate Figure 4 1 Double Pass Single BBO Crystal OPA 800CF 4 2 Due to the variation of beam size and
59. gth um Figure 3 8 Typical Output Tuning Curves for Wavelength Extensions for an OPA 800CP 1 Description Configuration The fs ps OPA SOOCFP layout is shown in Figure 3 9 The input amplified Ti sapphire beam is first reflected off two mirrors that flip the polarization from horizontal to vertical then is split into two legs In the first leg approximately 96 of the energy is transmitted and used for pumping the OPA The remaining lt 4 is reflected by beam splitter BS to produce a white light continuum that provides the seed pulse for the OPA A half waveplate and a thin film or cube polarizer control the beam energy and a lens focuses the beam into a solid state material where the continuum is generated It is re collimated and relayed to the OPA crystal through variable delay stage DELAY 1 Input Alternative Input 800 nm 800 nm Periscope PS Periscope 1 PS BS Ry Power Amp White Light Generator coc eer WLR or G Ra OR I l L C gt Wavelength Extension Option i ORo y y Residual Optional Signal Idler Optional Pump Pump for Pump for Second OPA Second OPA BS 2 Beam Splitter lo Irises Ro 5 Reflectors for 800 nm CL Collimating Lens Ly_4 Lenses Ty 2 Telescopes D 4 Dichroic Mirrors OR1 3 Output Reflectors WLP White light Plate FL Focusing Lens P Polarizer WLR 4_4 White light Reflectors G Grating PS 9 Periscope WP M2 Waveplate Figure 3 9 Double pass single BBO crystal OPA
60. h warning to allow action to avoid exposure to laser radiation 5 Verify that removing the cover of the pump laser shuts off the laser Verify that when the cover interlock on the pump laser is defeated the defeat mechanism is clearly visible and prevents installation of the cover until disengaged 2 3 OPA 800C Ultrafast Optical Parametric Amplifier CDRH CE Drawing 2 Output End View Input Side View Spectra Physics 1344 TERRA BELLA AVENUE MT VIEW CALIFORNIA 94039 MANUFACTURED VISIBLE AND INVISIBLE LASER RADIATION WHEN OPEN AVOID SKIN OR EYE EXPOSURE TO DIRECT OR SCATTERED RADIATION SEE MANUAL 0452 0150 VISIBLE AND INVISIBLE LASER RADIATION IS EMITTED FROM THIS APERTURE SEE MANUAL WITH 21 CFR 1040 AS APPLICABLE AVOID EXPOSURE MADE IN U S A MONTH YEAR_____ MODEL _____ S N Caution Noninterlocked Aperture Label 2 Housing Label 1 Serial Number CDRH Label 3 VISIBLE AND OR INVISIBLE LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT POWER WAVELENGTH S AND PULSE WIDTH DEPEND ON PUMP OPTIONS AND LASER CONFIGURATION SEE MANUAL 0451 8080 CE Aperture Label 4 CE Danger Label 5 Figure 2 3 OPA 800C Radiation Control Drawing 2 4 Label Translations Laser Safety For safety the following translations are provided for non English speak ing personnel The number in the first column cor
61. hapter 7 OPA 800C Options shows the layouts for optional second harmonic generation SHG of the signal and idler fourth harmonic generation FHG of the sig nal and idler sum frequency mixing SFM and difference frequency mix ing DFM OPAs and SPPOs operate on a very different principle from that of a laser A laser derives its gain from inverted population distribution between dif ferent atomic or molecular states These transitions have inherent line widths that govern the maximum tuning range of the laser e g a dye laser 3 1 OPA 800C Ultrafast Optical Parametric Amplifier 3 2 tunes over a range of 30 40 nm per dye while a Ti sapphire laser tunes over a 300 nm range In contrast an OPA or SPPO derives gain from a nonlinear frequency con version process Figure 3 1 illustrates a three wave interaction process which could be either down conversion a or up conversion b Wp 003 Figure 3 1 Optical frequency three wave interaction process This process originates from the interaction of the optical electromagnetic field with the bounded electrons in the nonlinear medium It is governed by Maxwell s equation V E o ue E gt uP 1 where E is the electromagnetic field u is the vacuum magnetic permeabil ity is the dielectric permeability u is the magnetic permeability ois the ohmic conductivity and P is polarization The nonlinear polarization P has three different frequency
62. hat is part of the holder When the holder is removed from the mount the spring is released and these three parts will fall apart unless held together If they fall apart reassem ble them as shown in Figure 5 6 Caution W The crystal holder comprises three parts that are clamped together in the a Remove the crystal holder from the mount by turning the clamping screw on the top holder clockwise to compress the spring mecha nism then carefully slide the holder out of the mount h Caution U OPA 800CP Installation and Alignment Place some lens tissue under the crystal mount to prevent the crys tal from directly falling onto the base plate if it becomes loose b Assemble the ps 3 piece crystal holder and carefully slide it into place in the mount Note which side of the yoke is the inner side that goes next to the mount Do not get the yoke and crystal turned around c Tighten the clamp by turning the screw counterclockwise until the holder assembly feels securely in place typically less than 1 turn If you turn the screw too far the screw will come out Change the L lens in T to a lens with a focal length of 50 mm Increase the separation between L and L by a moving L away from L to the next 14 20 threaded hole and b moving the L lens bracket backward by 6 3 mm Figure 5 7 shows how to change the L mount for ps operation In order to easily access the adjustment screw of L you can assemble the top
63. he changes in WL intensity Warning W Avoid focusing the pre amplification pump beam onto D or Rs 13 Gradually enlarge the pre amplifier beam size at the BBO crystal by slowly translating L closer to L so that a smaller amount of OPG emerges but so that there is still substantial WL amplification Verify the latter by placing a card in front of CL to interrupt the WL seed If after several attempts at performing Steps 12 and 13 you could not obtain amplification check the WL and pre amplifier beam overlap and verify that DELAY 1 scans through a larger range Power Amplification Stage l 2 10 Block the pre amplifier beam just before L To keep from damaging the BBO crystal and all the optics down stream de focus the power amplifier beam by translating L of T closer to Lg Place a white business card in front of Rs Translate L to collimate the power amplifier beam between R and Rs Lower the Spitfire Hurricane amplifier output by retarding the switchout time by 100 ns in the Spitfire Hurricane SDG see Spitfire Hurricane user s manual and let the small energy beam hit R and D and the BBO crystal Adjust R and D to align the power amplifier beam to the BBO crystal so that it propagates collinearly with the reflected WL from WLR Use a white card to block the power amplifier beam in front of Ly Re adjust the electronic delay of the Spitfire Hurricane SDG back to its normal position for specified
64. ht posi tion Lower the white light pump energy Check the pulse duration and make sure it meets the speci fied requirements Increase the energy to meet regenerative amplifier specifi cations Optimize it by steering the regenerative amplifier pump beam Aperture the regen beam mode using the intra cavity irises Refer to the Spitfire or Hurricane amplifier user s manual Adjust the seed wavelength slightly refer to your Tsunami or Mai Tai user s manual Verify the pump energy stability is within 3 Make sure the pump pulse width is stable Translate the FL back and forth and look for a position with stable WL generation Symptom No pre amplifier amplification Possible Causes Corrective Action The BBO crystal angle is incorrect Poor spatial overlap Pre amplifier pump beam intensity is too low Beams are not temporally overlapped Set the BBO crystal angle for the desired wavelength Overlap the white light with the pre amplifier pump beam between D and WLR Tighten its focusing by moving L until you see some OPG Change DELAY 1 and search for amplification using ir detectors Verify the CL stage does not interfere with the movement of DELAY 1 Verify WLP is not mounted in the farthest position from FL Symptom No power amplifier amplification Possible Causes Corrective Action The BBO crystal angle is incorrect Poor spatial overlap Power amplifier pump beam i
65. ify the mask is properly aligned with the stretcher Service and Repair Symptom Unstable OPA output signal idler Possible Causes Corrective Action White light is unstable Amplifier output is unstable Oscillator output wavelength or pulse energy is unstable White light is too strong or too weak See Low output causes Adjust the pump power and focusing to stabilize the white light See the Spitfire or Hurricane manual troubleshooting section Sometimes changing the SDG switch in out by 1 2 ns will sta bilize the output Optimizing the power wavelength of the oscillator may help Adjust the seed wavelength slightly for stable output Optimize it by adjusting WP See Low output correct actions Symptom Non Gaussian spectrum shape Possible Causes Corrective Action Non optimized OPA output Pump wavelength is not at 800 nm Beam spectrum is asymmetrical Side lobes are seen on the spectrum Poor crystal orientation Poor crystal angle Notches on the spectrum Optimize the output of the OPA 800CP see above Verify the pump wavelength is 800 5 nm Optimize DELAY 2 DELAY 1 and the grating angle Optimize the white light seed and verify it is overlapped with the pump beams Verify that the diffracted beam to the BBO crystal and the power amplifier pump beam are overlapped and are propagating col linearly Verify the correct crystal is used in each position and th
66. into OPA SOOCP Carefully position the OPA SOOCP so that the beam after PS hits the center of R Place standard table screws through the three plugged holes in the base plate and secure the OPA SOOCP to the optical table Steer PS and R so that the pump beam is centered on irises and l and make sure the beam is turned 90 through PS and is 6 3 cm above the base plate use an alignment card Reposition PS if necessary 5 3 OPA 800C Ultrafast Optical Parametric Amplifier Alignment White Light Generation 5 4 Note a Note a Warning W l T Place beam blocks such as white business cards before telescopes T and T and the WLP see Figure 5 1 Adjust BS to center the beam on waveplate WP and align the beam along the center line of the white light generator arm so that it is 6 3 cm above and parallel to the base plate Place a power meter after lens FL and adjust WP so that the meter reads 12 4 uJ energy per pulse 12 4 mW at 1 kHz operation Place a business card before lens CL Remove the power meter Move the FL translation stage away from polarizer P then move it back and forth with your fingers to search for white light generation on the business card By translating the FL and optimizing the pulse duration a symmetrical WL beam should appear with a green and white center about 2 3 mm dia surrounded by a weak bluish outside ring about 6 mm dia right after the collimation lens Us
67. ion Safety for Laser Products Refer to the CE Declaration of Conformity statements in Chapter 2 Should you experience any problems with any equipment purchased from Spectra Physics or you are in need of technical information or support please contact Spectra Physics as described in Customer Service This chapter contains a list of world wide Spectra Physics service centers you can call if you need help Every effort has been made to ensure that the information in this manual is accurate All information in this document is subject to change without notice Spectra Physics makes no representation or warranty either express or implied with respect to this document In no event will Spectra Physics be liable for any direct indirect special incidental or consequential dam ages resulting from any defects in this documentation Finally 1f you encounter any difficulty with the content or style of this manual or encounter problems with the laser itself please let us know The last page of this manual is a form to aid in bringing such problems to our attention Thank you for your purchase of a Spectra Physics instrument CE Environmental Specifications CE Electrical Equipment Requirements For information regarding the equipment needed to provide the electrical service listed under Service Requirements at the end of Chapter 3 please refer to specification EN 309 Plug Outlet and Socket Couplers for Indus trial
68. it and squeeze a drop or two of acetone or meth anol on to it b Slowly draw the tissue across the surface to remove dissolved con taminants and to dry the surface Pull the tissue slowly enough so the solvent evaporation front follows the tissue 1 e the solvent dries only after leaving the optic surface 4 After replacing the optic you just cleaned in the beam inspect it using an ir viewer or a collimated light source recommended to verify that the optic is actually cleaner 1 e you did not replace one contaminant with another General Procedure for Cleaning the Crystal Warning W n Caution W h Caution W Do not clean the crystal unless absolutely necessary It can be des troyed 1f excess pressure is used Do not use acetone or methanol on the crystal Use a spectrophotomet ric grade hydrocarbon solvent such as toluene or xylene to clean the crystal Do not allow the solvent to touch the mounting plate or 1t will destroy the glue holding the crystal to the mount Such damage is not covered under your warranty Do not remove the crystal for cleaning Clean it in place l Block the input beam to the OPA 800C then wait about 5 minutes for the crystal to cool down Use a squeeze bulb to clean away any dust or grit Proceed with clean ing the crystal with a spectrophotometric grade solvent only 1f clean ing with air was not effective Use a tissue in a hemostat to clean the crystal a Fold a piece
69. ization is off Make sure it is the same for other wavelengths BBO angle is not optimized Optimize the BBO crystal for power Symptom Lower output in HG SFM DFM Option Possible Causes Corrective Action Output beam is too large Optimize the size of the pump beams by adjusting L and or L Use the collimation lenses for HG for the idler beam and DFM Output beam is too small Do not use collimation lenses in the signal HG and SFM options Optimize the size of the pump beams by adjusting L Pulse duration is too long Optimize the OPA pump pulse duration using the Spitfire con troller Make sure the correct OPA crystal is used Crystal orientation is wrong Check the operation procedures in Chapters 5 7 Temporal overlap inadequate Adjust DELAY 2 for best DFM SFM output Long pass filter orientation is wrong Try flipping the long pass filter T is not optimized Translate L for best FHG SHG output power mode Symptom HG spectrum spectral width is incorrect Possible Causes Corrective Action Wrong crystal installed Verify the correct thickness crystal is installed see Chapter 7 Verify the SHG and FHG crystals are not exchanged or mis placed Imperfect pump beam Improve the pump beam quality in this region using the aper ture Avoid clipping the beam OPA pump beam is not optimized Optimize the pump beam Do not make the power pump beam too small Symptom DFM spectrum has side lobes
70. kameguro Meguro ku Tokyo 153 Telephone 81 3 3794 5511 Fax 81 3 3794 5510 Japan West Spectra Physics KK West Regional Office Nishi honmachi Solar Building 3 1 43 Nishi honmachi Nishi ku Osaka 550 0005 Telephone 81 6 4390 6770 Fax 81 6 4390 2760 e mail niwamuro O splasers co jp United Kingdom Telephone 44 1442 258100 United States and Export Countries Spectra Physics 1330 Terra Bella Avenue Mountain View CA 94043 Telephone 800 456 2552 Service or 800 SPL LASER Sales or 800 775 5273 Sales or 650 961 2550 Operator Fax 650 964 3584 e mail service O splasers com sales splasers com Internet www spectra physics com And all European and Middle Eastern countries not included on this list And all non European or Middle Eastern countries not included on this list 10 3 OPA 800C Ultrafast Optical Parametric Amplifier 10 4 Appendix A Danger W Pumping an OPA 800CP with Spitfire This appendix gives you a simple guideline for setting up a fs pulse seeded spectrally masked ps Spitfire to pump your Spectra Physics OPA SOOCP The requirements for Spitfire output are gt 1 mJ pulse energy 22 cm of bandwidth at 800 2 nm and lt 1 6 ps in pulse width Do not pump the OPA 800CP while you are working on the Spitfire In order to generate a bandwidth of less than 25 cm for the OPA 800CP the Spitfire output bandwidth has to be lt 25 cm typically lt 22 c
71. le A 1 Spectral bandwidth at 800 nm vs the width of the mask slit for a ps masked Spitfire Mask Slit width Measured bandwidth unit and P N mm nm cm 1 9780 7 5 0 95 15 0 2 9781 8 3 1 05 16 4 3 9782 9 1 1 15 18 0 4 9783 9 9 1 25 19 5 5 9784 10 7 1 35 21 1 This set of fixed width masks is supplied with your ps OPA to be selec tively used to achieve the appropriate output bandwidth They are fully tested and work well with the ps OPA but the amount of energy required to pump the white light should be adjusted accordingly and the two tele scopes in both pump beams should also be adjusted accordingly to obtain optimum output Make sure the first and the last beam spots on the stretcher grating are in a single vertical line Otherwise check the stretcher alignment before turning on the amplifier The amplifier should be seeded with gt 350 mW of Tsunami power and the power seeding the regenerative amplifier should be 225 mW The Spitfire should generate 1 mJ pulse energy after the compression stage The output spectrum shape is squarish Refer to the Spitfire user s manual for general information on operating the ps masked Spitfire In the compressor the compression grating needs to be mounted correctly in order to compress all the seeded spectrum Sometimes part of the spec trum misses the grating If this occurs mount the compressor grating for ward and slide the compression grating off center or slide the whol
72. ligned refer to the appropriate installation and alignment instructions in Chapter 4 fs or 5 ps Standard Cleaning Procedures 8 2 Follow the principles below whenever you clean any optical surface 1 Clean only one element at a time then realign that element for maxi mum output power Only remove an optic for cleaning when it cannot be accessed in its optical mount If optics are removed and replaced as a group some might get swapped At best all reference points will be lost making realignment extremely difficult 2 Work in a clean environment and whenever possible over a soft lint free cloth or pad 3 Wash your hands thoroughly with liquid detergent Body oils and con taminants can render otherwise fastidious cleaning practices useless 4 Always use clean powderless and lint free finger cots or gloves when handling optics and intracavity parts Remember not to touch any con taminating surface while wearing gloves you will transfer oils and acids on to the optics Maintenance 5 Use a rubber squeeze bulb to blow dust or lint from the optic surface before cleaning it with solvent permanent damage can occur if dust scratches the glass or mirror coating ture due to freon sputter can cause permanent damage to the crystal i Caution W Do not use canned air to clean the crystal A rapid change in tempera Freon sputter is common if the can is not held vertically 6 Use spectroscopic grade solvents to clea
73. line up vertically Remove the card from in front of L and let the pre amplifier beam amplify the WL Move DELAY 2 back and forth until you see an amplification flash of the power amplifier beam in front of OR then using a power meter adjust DELAY 2 for maximum amplifier output power Optimize output power by adjusting DELAY 1 DELAY 2 D D and CL Re mount the grating mount to the upper 8 32 threaded hole of the mounting plate Set the grating angle and the BBO crystal to the angles corresponding to A 1 3 um according to the setting listed in the OPA 800CP Final Test Performance Summary Sheet or see Figure 6 4 Scan the crystal angle or the grating angle within a small range to find a flash of the power amplifier beam then adjust for maximum optical output Optimize output power again by adjusting DELAY 1 DELAY 2 D D and the BBO crystal angle Optimize output power by adjusting the delay in the Spitfire Hurricane compressor If Steps 18 19 are unsuccessful you may have to try several times However you should always be able to find the power amplification by adjusting DELAY 2 while scanning the grating angle With mJ 1 5 ps pulse pumping the output energy signal idler of this OPA SOOCP should be between 90 and 140 uJ for most of its spectral range To further improve the stability of the OPA SOOCP output optimize the Spitfire Hurricane SDG switch in and switch out timing by changing them in ns increment
74. listing components that can be replaced by you for the fs and ps systems The OPA 800C is a passive unit typically pumped by a Spitfire or Hurri cane Ti sapphire amplifier and seeded by a Tsunami Ti sapphire oscilla tor which is pumped by a Millennia diode pumped green laser or a Mai Tai Ti sapphire oscillator As such it is important to pay close attention to the OPA 800C pump pulse spatial and temporal qualities whenever the OPA 800C output does not meet specifications This troubleshooting guide includes some corrections that can be made to the Ti sapphire amplifier and oscillator when needed This guide assumes you are using Spectra Physics Tsunami or Mai Tai Spitfire or Hurricane and pump lasers Troubleshooting Guide The comments below are intended to help you resolve poor performance from the OPA SOOC However for complete alignment and operating pro cedures of the seed laser and regenerative amplifier please refer to the appropriate user s manual 9 1 OPA 800C Ultrafast Optical Parametric Amplifier Part I OPA 800CF Symptom Unstable or No white light Possible Causes Corrective Action The white light pump energy is too high The pump pulse duration is incorrect The pump pulse energy is too low or too high The pump beam spatial mode is bad The pump beam can not be focused The seed wavelength drifted Unstable pump pulse energy duration The white light plate is not at the rig
75. m is required To achieve this it is necessary to first ensure that the ps Spitfire gratings 2200 g mm are installed and that a spectral mask is placed inside the stretcher to select a small portion of the seed spectrum since we use fs pulses to seed the Spitfire A basic stretcher setup with a mask installed is shown in Figure A 1 Folding Mirror gt AN PS Nott Curved Mirror ps Mask Stretcher Grating Compressor Grating Figure A 1 Schematic of a Stretcher with ps Mask The curved mirror has a radius of curvature of 166 cm or a focal length of 83 cm at normal incidence If the curved mirror has a large curvature be careful that the spectrum reflected back from the curved mirror is centered on the notch on the mask Both stretcher and compressor gratings should be 2200 g mm The stretcher grating should be about 41 cm away from the 1 x 4 in folding mirror and the mask has to be about 41 cm away from the grating in front of the curved mirror Place the incidence angle at 55 1 and the diffracted 800 nm beam will be 70 3 1 7 The angle between the incident and diffracted beams should be 15 2 for a standard Spitfire Clip only the top spectrally spread beam on the mask by using the top fixed width notch of the mask For this configuration the bandwidth of the spectrum coming out of the Spitfire versus the different masks 1s listed in Table A 1 A 1 OPA 800C Ultrafast Optical Parametric Amplifier A 2 Tab
76. m Pump Input Not for specified performance B 3 Table B 4 Corresponding OPA 800C Output Wavelengths for an 810 nm Pump Input Not for specified performance B 4 Table B 5 Corresponding OPA 800C Output Wavelengths for an 825 nm Pump Input Not for specified performance B 5 Danger Laser Radiation Danger Danger Warning ESD h Caution Don t Touch Eyewear Required Y Y Y Y A S A Warning Conventions The following warnings are used throughout this manual to draw your attention to situations or procedures that require extra attention They warn of hazards to your health damage to equipment sensitive procedures and exceptional circumstances All messages are set apart by a thin line above and below the text as shown here Laser radiation is present Condition or action may present a hazard to personal safety Condition or action may present an electrical hazard to personal safety Condition or action may cause damage to equipment Action may cause electrostatic discharge and cause damage to equip ment Condition or action may cause poor performance or error Text describes exceptional circumstances or makes a special refer ence Do not touch Appropriate laser safety eyewear should be worn during this opera tion Refer to the manual before operating or using this device Xi Standard Units The following units abbreviations and prefixes are used in this S
77. n all optics except the crystal Use spectrophotometric grade hydrocarbon solvents to clean the crys tal Since cleaning simply dilutes contamination to the limit set by solvent impurities solvents must be as pure as possible Use solvents spar ingly and leave as little on the surface as possible As any solvent evap orates 1t leaves impurities behind in proportion to its volume 7 Store all solvents in small glass bottles Solvents collect moisture dur ing prolonged exposure to air Avoid storing solvents in bottles where a large volume of air is trapped above the solvent 8 Use Kodak Lens Cleaning Paper or equivalent photographic clean ing tissue to clean optics 9 Use each piece of lens tissue only once dirty tissue merely redistrib utes contamination it does not remove it Caution Do not use lens tissue designated for cleaning eye glasses Such tissue A N U contains silicones These molecules bind themselves to the optic coat ings and can cause permanent damage Also do not use cotton swabs e g Q Tips Solvents dissolve the glue used in the cotton tip resulting in contaminated coatings Only use photographic lens tissue to clean optical components General Procedures for Cleaning all Optics Except the Crystal and Grating ps only Warning Do not use these instructions for cleaning the crystal Refer to General Procedures for Cleaning the Crystal later in this chapter Most optics can be cleaned in
78. n lieu of all other warranties expressed or implied and does not cover incidental or consequential loss The above warranty is valid for units purchased and used in the United States only Products with foreign destinations are subject to a warranty surcharge Return of the Instrument for Repair 10 2 Warning W Contact your nearest Spectra Physics field sales office service center or local distributor for shipping instructions or an on site service appointment You are responsible for one way shipment of the defective part or instru ment to Spectra Physics We encourage you to use the original packing boxes to secure instruments during shipment If shipping boxes have been lost or destroyed we recom mend you order new ones Spectra Physics will only return instruments in Spectra Physics containers Always drain the cooling water from the laser head before shipping Water expands as it freezes and will damage the laser Even during warm spells or summer months freezing may occur at high altitudes or in the cargo hold of aircraft Such damage is excluded from warranty coverage Service Centers Customer Service Benelux Telephone 31 40 265 99 59 France Telephone 33 1 69 18 63 10 Germany and Export Countries Spectra Physics GmbH Guerickeweg 7 D 64291 Darmstadt Telephone 49 06151 708 0 Fax 49 06151 79102 Japan East Spectra Physics KK East Regional Office Daiwa Nakameguro Building 4 6 1 Na
79. nergy in the table For the OPA pumped by the Spitfire Hurricane USF lt 80 fs the output energy is 75 of the corresponding energy of the standard OPA For the OPA pumped by the Spit fire Hurricane 50 fs lt 50 fs the output energy is 70 of the corresponding energy of the standard OPA Specifications apply to operation at the wavelength noted A Gaussian pulse shape is used to determine the pulse width from the autocorrelation X 0 71 For the OPA pumped by Spitfire Hurricane USP please contact Spectra Physics for the option s output pulse width gt pulse to pulse stability Table 3 4 Specifications of OPA 800CP Wavelength Extension Options Option Wavelength Range Pulse Energy Pulse Width Energy Stability Q 1 6 um to 3 0 um 25 uJ at 2 0 um lt 25 cm lt 3 a 1 1 um to 1 6 um 60 uJ at 1 3 um lt 25 cm lt 3 HGI HGII 2 800 nm to 1 2 um 7 uJ at 900 nm lt 25 cm lt 5 HGI HGII 2 580 nm to 800 nm 14 uJ at 650 nm lt 25 cm lt 5 HGI HGII 4 400 nm to 600 nm 2 uJ at 450 nm lt 30 cm lt 7 5 HGIl 4a 300 nm to 400 nm 4 uJ at 330 nm lt 30 cm lt 7 5 SFM Q Q 480 nm to 533 nm 30 uJ at 500 nm lt 25 cm lt 5 SFM Q Q 533 nm to 600 nm 20 uJ at 560 nm lt 25 cm lt 5 DFM Q Q 3 0 um to 10 um 3 uJ at 4 0 um lt 25 cm lt 5 Due to our continuous product improvement specifications are subject to change without notice and only apply when the OPA SOOCP is pumped by Spectra Physic
80. ng assembly e acollimation lens for ps operation e a cube polarizer with mount OPA 800C Ultrafast Optical Parametric Amplifier Upgrade From a ps OPA 800CP to a fs ps OPA 800CFP Harmonic Generation This option allows you to change a ps unit to one capable of fs operation Once upgraded you can change back and forth between ps and fs configu rations This conversion kit includes e a L R reflector beam splitter e fs white light plate e afs OPA SOOCF crystal e a curved reflection mirror with mount e asignal beam rejection mirror with mount e acollimating lens HGI Harmonic Generation 2q 2q 4q Extends wavelength coverage from 400 nm to 1 2 um via second harmonic generation of the signal and idler and fourth harmonic generation of the idler All harmonics demonstrate a spectral purity ratio of better than 100 1 With the direct output of the OPA SOOC the system delivers complete wavelength tuning from 400 nm to 3 um By switching harmonic crystals the system can also be configured for 40 20 or 20 HGI HGII Harmonic Generation 2q 2q 4 4q Provides all the performance of the HGI option but also extends the uv wavelength coverage from lt 300 nm to 400 nm through fourth harmonic generation of the signal The 44 output has gt 10 1 spectral purity The HGI or HGII harmonic generation options include e 2crystals for an OPA SOOCF 3 crystals for an OPA SOOCP HGII and 2 crystals for an OPA 800CP HGI e 2 pola
81. nstrumentation IEC 309 Plug Outlet and Socket Coupler for Industrial Uses Tel 41 22 919 0211 Fax 41 22 919 0300 Internet http ftp 1ec c h Cenelec European Committee for Electrotechnical Standardization Central Secretariat rue de Stassart 35 B 1050 Brussels Document Center 1504 Industrial Way Unit 9 Belmont CA 94002 4044 Tel 415 591 7600 2 7 OPA 800C Ultrafast Optical Parametric Amplifier Equipment and Training 2 8 Laser Safety Guide Laser Institute of America 12424 Research Parkway Suite 125 Orlando FL 32826 Tel 407 380 1553 Laser Focus World Buyer s Guide Laser Focus World Penwell Publishing 10 Tara Blvd 5 Floor Nashua NH 03062 Tel 603 891 0123 Lasers and Optronics Buyer s Guide Lasers and Optronics Gordon Publications 301 Gibraltar Drive P O Box 650 Morris Plains NJ 07950 0650 Tel 973 292 5100 Photonics Spectra Buyer s Guide Photonics Spectra Laurin Publications Berkshire Common PO Box 4949 Pittsfield MA 01202 4949 Tel 413 499 0514 Chapter 3 Introduction Theory Description Since the early 1990s the mode locked Ti sapphire laser has become the system of choice for ultrafast laser applications The Spectra Physics Tsu nami mode locked Ti sapphire oscillator provides the most flexible com mercial system with a wavelength coverage from 690 to 1080 nm b a pulse width range from lt 35 fs to gt 80 ps c average power of up t
82. nt mid infrared wavelengths that are required for investigating time resolved vibrational processes in molecular systems This is because the nonlinear crystals suitable for this difference frequency mixing process have better transparency and a more favorable GVM for the signal and idler wave lengths 1 1 to 3 0 um With high energy pump pulses spatial walk off is less of a problem due to the loose focusing geometry in the OPA The second harmonic generation and sum frequency mixing shown in Fig ure 3 1b could be viewed as the inverse process of the parametric down conversion shown in Figure 3 la However parametric down converted signal and idler waves could build up from either the quantum noise or from a seeded beam All OPAs require a pre stage to generate the seed wave either through parametric fluorescence superfluorescence 1 e opti cal parametric generation OPG initiated from quantum noise or through white light generation A superfluorescence seed can be generated using the same OPA crystal at the same phase matched angle However since it is generated by tightly focusing a small amount of split off pump beam into the crystal the result ant superfluorescence becomes color separated and its stability is extremely sensitive to small variations when tuning the output wavelength White light generation on the other hand is a higher order nonlinear pro Description cess that includes self phase modulation self focusin
83. ntensity is too low Beams are not temporally overlapped Set the BBO angle for the desired wavelength or for A 1 3 um Verify the power amplifier pump beam is overlapped with the pre amplifier WL beam Tighten its focusing gradually until you see proper amplifi cation but no OPG white light generation Verify the L stage does not interfere with the movement of DELAY 2 Symptom Low OPA output signal idler Service and Repair Possible Causes Corrective Action The BBO angle is incorrect The DELAYS are not optimized Pre amplifier pump beam does not overlap with the white light Pre amplifier and or power amplifier pump beam focusing are not optimized The pump pulse duration is too long The pump beam mode is bad The pump beam has moved Set the BBO crystal angle for the desired wavelength Optimize both DELAY 1 and DELAY 2 for power Steer the D mirror for higher power Adjust the focusing of the white light by translating CL for power Adjust L and or L for higher power but lt 10 uJ OPG Optimize the compressor grating separation in the Spitfire with the remote controller Aperture the amplifier output beam using the apertures in the regenerative amplifier cavity Optimize the green pump beam to the regen Refer to the Spitfire or Hurricane amplifier user s manual Steer periscope PS slightly to correct it Check the alignment of each arm in the OPA 800C Symptom Uns
84. o 2 W d outstanding long term stability and e active length stabilization for synchronization with external RF sources or other mode locked laser sources However many applications require access to wavelengths that are not directly covered by the fundamental Ti sapphire output or through its direct frequency conversion with harmonic generation Wavelength extensions to these regions have generally been accomplished through two approaches a amplification with white light continuum generation and or optical parametric amplification OPA and b a synchronously pumped optical parametric oscillator SPPO The former provides higher energies at lower repetition rates typically uJ mJ at kHz repetition rates while the latter provides nJ pulse energies at repetition rates of about 80 MHz Spectra Physics provides both SPPO and OPA systems The latter uses a white light continuum as a seed The Spectra Physics OPA 800C series is a compact package with two input port options to facilitate system setup with a minimum footprint Also by replacing the first reflector mirror in peri scope PS Figure 3 9 with a beam splitter the pump input can be split between the primary OPA and a secondary OPA or a single harmonic gen erator or other accessory Figure 3 10 through Figure 3 12 toward the end of this chapter show the mechanical optical parts layout for a fs OPA 800CF a ps OPA 800CP and a s ps OPA SOOCFP configured for fs operation C
85. of reducing objectionable materials to acceptable levels The condition of the laboratory environment and the amount of time the OPA 800C is operated affects its periodic maintenance schedule All coated optical surfaces such as the high reflector beam splitters dichroics lenses and crystal surfaces are easily contaminated Do not allow smoking in the laboratory the optics stay clean longer Con densation due to excessive humidity can also contaminate optical surfaces This is particularly true for the BBO crystal In short the cleaner the envi ronment is the slower the rate of contamination If the OPA SOOC cover is left in place there is little that must be done day to day to maintain the system When you finally do need to clean the optics follow the procedures below e Rubber squeeze bulb e Optical grade lens tissue e Spectrophotometric grade methanol and or acetone for general optics e Spectrophotometric grade HPLC toluene or xylene Aldrich Gold Label for cleaning the crystal e Hemostats e Clean lint free finger cots or powderless latex gloves 8 1 OPA 800C Ultrafast Optical Parametric Amplifier Removing and Cleaning OPA 800C Optics Danger Laser Radiation The Tsunami oscillator and its pump laser or the Mai Tai oscillator and the Spitfire regenerative amplifier and its pump lasers or Hurri cane regenerative amplifier are Class IV High Powers lasers and with the OPA 800C have output beam
86. on of the OPA It concludes with OPA 800C system specifications and outline drawings The middle chapters guide you through the setup installation alignment and operation of the OPA SOOC The last part of the manual covers mainte nance and service The Maintenance section contains information required to keep your OPA 800C clean and operational on a day to day basis Service and Repair is intended to help guide you to the source of any problems A replacement parts list is included as well as a troubleshooting guide Do not attempt repairs by yourself while the unit is still under warranty Instead report all problems to Spectra Physics for warranty repair Customer Service contains a general warranty statement and it explains how to request service should you ever need it Included 1s a list of Spectra Physics world wide service centers This product has been tested and found to conform to Directive 89 336 EEC for electromagnetic Compatibility Class A compliance was demon strated for EN 50081 2 1993 Emissions and EN 50082 1 1992 Immu nity as listed in the official Journal of the European Communities It also meets the intent of Directive 73 23 EEC for Low Voltage Class A compli ance was demonstrated for EN 61010 1 1993 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory use and OPA 800C Ultrafast Optical Parametric Amplifier EN 60825 1 1992 Radiat
87. order idler and first and sec ond order signal seeded case grating angles for the 600 g mm grating provided with the system By comparing the required grating angle for the first order idler seeded case versus that for the second order signal seeded case and knowing the grating angle for the first order diffracted idler seed versus the micrometer reading you can set the grating micrometer to seed the OPA SOOCP with the second order diffracted signal beam The calculated grating angles listed in Table 6 1 can help you do this If the power amplification beam is not aligned and or not synchronized well with the pre amplified white light you may see three separate output spots at OR If these three spots are separated in a single vertical line bring them together by adjusting the DELAY 2 If they fall into a line but off verti cal then either the power amplifier beam is not perfectly collinear with the seed beam which is diffracted by the grating or the grating groove orien tation is not parallel to the BBO crystal or the base plate This spatial over lap can be corrected by aligning the second pump beam through the R and D mirrors or by orienting the grating grooves so that the diffracted beam is Operation vertical and also by optimizing DELAY 2 To set up the grating groove ori entation correctly follow the steps under Grating Setup in Chapter 5 If the separated spots fall into one vertical line while changing the grating
88. otes Notes 3 OPA 800C Ultrafast Optical Parametric Amplifier Notes 4 Notes Notes 5 OPA 800C Ultrafast Optical Parametric Amplifier Notes 6 Report Form for Problems and Solutions We have provided this form to encourage you to tell us about any difficul ties you have experienced in using your Spectra Physics instrument or its manual problems that did not require a formal call or letter to our service department but that you feel should be remedied We are always interested in improving our products and manuals and we appreciate all suggestions Thank you From Name Company or Institution Department Address Instrument Model Number Serial Number Problem Suggested Solution s Mail To FAX to Spectra Physics Inc Attention SSL Quality Manager SSL Quality Manager 650 961 7101 1330 Terra Bella Avenue M S 15 50 Post Office Box 7013 Mountain View CA 94039 7013 U S A E mail sales splasers com www spectra physics com
89. ource to produce ampli fied signal and idler beams Nonlinear Crystal Pump Signal Idler Signal or Idler Seed Figure 3 2 Optical Parametric Amplification The parametric gain G at the phase matched condition is given by G adq 4 where I is the pump intensity The gain is then greater for shorter pump wavelengths higher pump intensities and when Q and 9 approach degener acy 1 e when Q This favors using the high energy second harmonic fs pulses from a Ti sapphire amplifier as the pump wavelength However another key consideration in the amplification of ultrashort pulses is the effective interaction length between the pump and signal or idler pulses In cases where pulse duration is from the tens of fs to the ps range high pump intensity is easily achieved by reducing the beam size as long as it remains below the damage threshold of the nonlinear material A high damage threshold high nonlinear polarization coefficient and a large trans parent wavelength range are major requirements when choosing a crystal for the nonlinear medium In addition the phase matching condition must also be considered over the working wavelength range In the case shown in Figure 3 1a an input photon is split into two lower energy photons sig nal and idler photons and energy conservation determines the generated frequency or wavelengths 1 e Q Q Q 5 or 1 4 WA 1 2 6 Efficient conversion requires the best phas
90. out of the OPA 800CP 0 0 ce 3 14 Figure 3 12 Mechanical Layout of the OPA 800CFP 0 0 0 eee 3 15 Figure 3 13 The OPA 800C Outline Drawing 0 0 cee eee ees 3 18 Figure 4 1 Double Pass Single BBO Crystal OPA 800CF 0 2 ccc eee 4 2 Figure 4 2 A Typical OPA 800CF Table Layout 0 0 eee 4 3 Figure 4 3 WL beam location on the crystal in the crystal mount 0 000 c eee eee 4 5 Figure 4 4 L L Placement for ps and fs Configurations 0 0 eee ee 4 9 Figure 4 5 The ps and fs crystals with holders 0 0 0 ccc eee eens 4 9 Figure 4 6 Conversion of the ps OPA grating assembly to the fs curved mirror 4 10 Figure 5 1 Double Pass Single BBO Crystal OPA 800CP 0 ccc ee 5 2 Figure 5 2 Typical OPA 800CP Table Layout with optional second OPA 5 3 Figure 5 3 White light filament as seen in the white light plate o ooooooooo 5 5 Figure 5 4 WL beam location on the crystal in the crystal mount 2 0000 eee eee 5 5 Figure 5 5 OPA 800CP Grating Assembly 0 00 5 7 Figure 5 6 The ps and fs crystal holders 0 0 ccc eee teens 5 10 Figure 5 7 L L Placement for ps and fs Configurations 0 0 0 ee 5 11 Figure 6 1 Diffracted spectra as seen on the Spitfire Hurricane stretcher grating with examples of CW hot spots nananana naaa aaa 6 2 Figure 6
91. output energy level Put another white card in front of OR Turn off the room lights then remove the card from in front of L to see whether it generates OPG WL through the BBO crystal before OR then replace the white card quickly once a determination has been made 4 7 OPA 800C Ultrafast Optical Parametric Amplifier Note Note 11 2 13 14 15 16 Adjust L until the beam does not generate any OPG WL then remove the card from in front of L Adjust R and D so that the power amplifier beam is still collinear with the WL beam from WLR and so that is not clipped by the BBO crystal or D and so it passes through D Remove the card from in front of L and let the pre amplifier beam pump the BBO crystal and amplify the WL Adjust DELAY 2 back and forth until you see an amplification flash in front of OR that is caused by the power amplifier beam Using a power meter optimize output power by adjusting DELAY 1 and DELAY 2 adjusting D to overlap the pre amplifier beam with WL adjusting R and D to steer the power amplifier beam and adjusting CL Iteratively adjust DELAY 1 then DELAY 2 to obtain optimum output Typically there are several delay positions for DELAY 1 that provide amplification Usually the optimum output is obtained with the largest optical path length for both delays If at first Steps 14 16 are not successful in producing spec power try again several times You should alway
92. p wavelength accurately calculate the corresponding signal wavelength Follow the same procedure as above to select the calcu lated signal wavelength and the desired wavelength of the idler Please refer to the tables in Appendix A and B This completes the wavelength selecting procedure For operating a selected output option refer to Chapter 7 OPA 800CF Options OPA 800CP Wavelength Selection 6 4 In the OPA SOOCP either the signal or idler can be used as a seed beam However it is best to use the idler beam to seed the final amplification for most of the spectral range It permits continuous wavelength tuning over the full spectral range Wavelength selection is determined by the diffraction angle of the grating according to the diffraction formula in the Littrow diffraction configura tion 2Sin 0 mA A m 0 1 2 1 Operation Where 0 is the Littrow diffraction angle 4 is the wavelength A is the grat ing groove space and m is the diffraction order You can distinguish the idler seeded case from the signal seeded case by monitoring the wavelength change while tuning the grating angle The longer the diffracted wavelength the larger the grating angle If the OPA SOOCP is seeded with the idler then as the grating is tuned to a larger angle the selected idler wavelength becomes longer and the generated sig nal wavelength becomes shorter If it 1s signal seeded then as the grating is tuned to a larger
93. pectra Physics manual Quantity Unit Abbreviation mass kilogram kg length meter time second S frequency hertz Hz force newton N energy joule J power watt W electric current ampere A electric charge coulomb C electric potential volt V resistance ohm Q inductance henry H magnetic flux weber Wb magnetic flux density tesla T luminous intensity candela cd temperature celcius C pressure pascal Pa capacitance farad F angle radian rad Prefixes tera 103 T deci 100 d nano 10 n giga 109 G centi 107 c pico 103 p mega 10 M mill 10 m femto 105 f kilo 10 k micro 10 qu atto 10 a xiii List of Abbreviations Used in this Manual ac AR BBO CDRH CE CW dc fs GVD HR IR OC OPA OPO ps PZT RF SCFH SPM TEM Ti sapphire UV A alternating current antireflection Beta Barium Borate Center of Devices and Radiological Health European Community continous wave direct current femtosecond or 101 second group velocity dispersion high reflector infrared output coupler optical parametric amplifier optical parametric oscillator picosecond or 1071 second piezo elecric transducer radio frequency standard cubic feet per hour self phase modulation transverse electromagnetic mode Titanium doped Sapphire ultraviolet wavelength XV Unpacking Your System Your OPA 800C laser accessory was packed with great care and all con tainers were inspected prior
94. place Remove optics only when necessary it is best to not disturb the alignment by removing the optics 1 Use a squeeze bulb to clean away any dust or grit before cleaning optics with solvent If using canned air not recommended avoid tilt ing the can This prevents freon from being sputtered onto the optic OPA 800C Ultrafast Optical Parametric Amplifier 2 Use a tissue in a hemostat to clean the optic a Fold apiece of tissue in half repeatedly until you have a pad about one cm square and clamp it in a plastic hemostat Figure 8 1 Caution While folding do not touch the surface of the tissue that will contact the optic or you will contaminate the solvent b If required cut the paper with a solvent cleaned tool to allow access to the optic c Saturate the tissue with acetone or methanol shake off the excess re saturate and shake again Do not allow excess solvent to flow onto unwanted areas such as optic adhesives and mounts d Wipe the surface in a single motion from the setscrew toward the nylon holder Be careful that the hemostat does not touch the optic surface or the coating may be scratched 3 Clean the optic using the drop and drag method Figure 8 2 when you have to remove the optic Ss Figure 8 1 Lens Tissue Folded for Cleaning ny ae Figure 8 2 Drop and Drag Method Maintenance a Hold the optic horizontal with its coated surface up Place a sheet of lens tissue over
95. ptical Parametric Amplifier Pre amplification Stage 4 6 Warning ll Warning W Warning W The pre amplifier and power amplifier 800 nm pump beams should not be focused in the BBO crystal without careful monitoring The crystal can be easily damaged Small distance variations between L and L in T will cause a big change in the focus position of the pre amplifier beam Verify the pre amplifier beam is not focused on any optical surface before allowing it to hit that same sur face and always monitor it while adjusting the separation of L and L This 1s the pre amplification of the WL The amount of amplified WL is typically a few uJ before it hits the WLR Although you can see the amplification the use of a photodetector will simplify this search Do not perform these steps with the power amplifier beam present nor let any beams burn ink or other material onto the surface of the BBO crystal e g do not let the beam hit your alignment card when it is close to the crystal or optics Using a white card cut to Ya x 10 cm may reduce the chance of this happening l Block the two beams in front of T with white cards 2 Defocus the pre amplifier beam by translating L closer to L4 Keep the beam size from getting too small A beam that is too small will damage the BBO crystal With irises and l closed adjust BS so that the pre amplifier beam and the WL beam are overlapped right after D 4 Put a car
96. r is not stable or is not at the center of the WL beam reduce the pump energy lt 50 fs pulses by carefully rotating the WP If this is ineffective and this is a fs only OPA try rotat ing the thin film polarizer to create a large incidence angle to reduce the pump energy Take care to avoid the possibility of damaging components in the WLG 10 11 12 13 14 15 Once WL is obtained adjust R to direct the light onto the center of WLR Position the CL lens to center it in the WL beam Adjust WLR so the WL beam passes through D on the side closest to Lo Adjust WLR so that the WL beam passes through the BBO crystal near the inner side the mount side see Figure 4 3 and hits the center of WLR and WLR Steer WLR so that the reflected WL is 6 3 cm above the base plate and parallel to the short side of the base plate use an alignment card Focus the WL beam on the WLR by translating CL Adjust WLR to bounce the WL beam back through the outer half of the BBO crystal without clipping it with the crystal D or WLR and steer it through D to OR The WL spot on the BBO crystal should not move while varying DELAY 1 Once WL is generated you may need to repeat some steps in this sec tion to obtain a stable symmetrically distributed WL with a bluish green color in the middle surrounded by a yellowish ring Figure 4 3 WL beam location on the crystal in the crystal mount 4 5 OPA 800C Ultrafast O
97. r provides the second harmonic of the signal and idler and the fourth harmonic of the signal and idler e Difference frequency mixing DFM which combines the signal and idler beams in an AgGaS crystal for wavelengths from 3 to 10 um e Sum frequency mixing SFM which combines the idler beam with the pump beam in a type I BBO crystal for higher energies at 533 600 nm It also combines the signal beam and pump beams in a type II BBO crystal for higher energies at 480 533 nm for an 800 nm pumped OPA 800C Conversions and upgrades among these systems are straightforward If you purchased the signal idler only configuration you can add harmonic gener ation by purchasing the appropriate upgrade kit The initial upgrade must be performed by an authorized Spectra Physics service engineer but once installed you can convert between the various configurations yourself Your system can be adapted for fs to ps conversion or vice versa at the time of purchase or a conversion kit can be purchased at a later time For more information on upgrades please contact your Spectra Physics sales representative Upgrade From a fs OPA 800CF to a fs ps OPA 800CFP This option allows you to change a ps unit to one capable of fs operation Once upgraded you can change back and forth between ps and fs configu rations This conversion kit includes e a4 reflector beam splitter e aps white light plate e aps OPA SOOCP crystal e a wavelength tuning grati
98. rated harmonic generation HGI and HGII sum frequency mixing SFM and difference frequency mixing DFM options These systems can also be converted from fs to ps operation and vice versa Input Alternative Input 800 nm 800 nm Y Periscope PS Periscope 1 PS BS Ry T lt gt Y Delay 2 pS T a BS Ip l4 R l l 3 a A 2 wig E Power Amp R gt i White Light o l C WP Generator l WLR or G LI Ra i D D OR l l i D WLR WLRo BBO Crystal O i lt gt SEAS A Delay 1 APS OR E gt C gt Wavelength Extension Option gt gt OR gt Y _ Y y Residual Optional Signal Idler Optional Pump Pump for Pump for Second OPA Second OPA BS 2 Beam Splitter 4 9 Irises Ro 5 Reflectors for 800 nm CL Collimating Lens Ly_4 Lenses Ty 2 Telescopes D4_4 Dichroic Mirrors OR1 3 Output Reflectors WLP White light Plate FL Focusing Lens P Polarizer WLRy_4 White light Reflectors G Grating PS 2 Periscope WP M2 Waveplate Figure 1 2 The OPA 800C Beam Path Configurations Available Options Introduction The fs and ps OPA S00Cs are available in five configurations that generate the following e Signal and idler beams only e Signal and idler beams with the harmonic generation option HGI The latter provides the second harmonic of the signal and idler and the fourth harmonic of the idler e Signal and idler beams with the harmonic generation option HGH The latte
99. ratory conditions 3 Verify that the Tsunami or Mai Tai power and wavelength are set to the required settings 6 1 OPA 800C Ultrafast Optical Parametric Amplifier Using an infrared viewer look at the Spitfire or Hurricane grating see Figure 6 1 and verify that the Tsunami or Mai Tai bandwidth has no CW breakthrough Adjust the Tsunami or Mai Tai amplifier as neces sary to ensure the spectrum is free of any CW component or Q switched mode locking cw Hot Spots e Input beam O Output beam Chirped Pulses Figure 6 1 Diffracted spectra as seen on the Spitfire Hurricane stretcher grating with examples of CW hot spots 5 6 10 11 12 Turn on the Merlin or Evolution power supply and cooling chiller Turn on the Merlin or Evolution controller s LAMP ENABLE and SHUT TER and verify the Q switch is set to on If no CW was observed in Step 4 turn on the Spitfire or Hurricane OUTPUT ENABLE on its SDG controller Verify that Spitfire Hurricane output power mode and pulse width meet the pumping requirements of the OPA 800C see Tables 3 1 and 3 2 Use a single shot autocorrelator such as a Spectra Physics SSA to measure pulse width Allow the Spitfire Hurricane output beam to enter the OPA 800C remove the power meter if necessary and allow the OPA 800C to warm up for a few minutes Adjust the OPA SOOC delays for optimum output power Adjust the OPA 800C BBO crystal angle for optimum outp
100. rds P N 0454 1260 xvii Chapter 1 Introduction The OPA 800C System The Spectra Physics OPA SOOC produces high energy fs and or ps pulses that are tunable over a broad wavelength region It is designed for use with a Spectra Physics ultrafast Ti sapphire amplifier system which comprises a mode locked Ti sapphire oscillator such as the Mai Tai or a BeamLok or Millennia cw pump laser and Tsunami mode locked laser and a chirped pulse Ti sapphire regenerative amplifier system which comprises a Merlin intracavity doubled Nd YLF pump laser or Evolution diode pumped laser and a Spitfire amplifier or the one box all diode pumped Hurricane amplifier Figure 1 1 The OPA 800C Optical Layout OPA 800C Ultrafast Optical Parametric Amplifier The OPA SOOC consists of a single optical head Figure 1 1 that is designed to be placed near the output of the Spitfire Hurricane amplifier Infrared wavelength extension is accomplished in a two stage process with white light continuum generation and traveling wave optical parametric amplification In a fs system the output wavelength is changed by angle tuning the B barium Borate BBO crystal In ps systems both the BBO crystal and the grating are tuned to change the output wavelength Synchro nized signal idler and residual pump beams are provided through three separate exit ports Further wavelength coverage in the visible and mid infrared spectral regions is possible using integ
101. rements temporarily block the transmitted beam through the first mirror of PS 5 x 10 Foot Table Millennia S Merlin OPA 800C gt a A Typical Spitfire and OPA 800C System Layout with optional second OPA 4 x 8 Foot Table Hurricane OPA 800C OPA 800C b A Typical Hurricane and OPA 800C System Layout with optional second OPA Figure 4 2 A Typical OPA 800CF Table Layout 4 3 OPA 800C Ultrafast Optical Parametric Amplifier 7 n Caution W Alignment Carefully position the OPA SOOC and or PS so that the beam after PS hits the center of R4 For dual OPA operation or whenever you need to split part of the pump beam for use elsewhere make sure the transmitted part of the pump beam through PS 1s centered on the optional pump beam exit port and temporarily block it while you align the first OPA Place standard table bolts through the three plugged holes in the base plate and secure the OPA SOOCF to the optical table Steer PS and R so that the pump beam is centered on both irises l4 and and make sure the beam is turned 90 through PS and is 6 3 cm above the base plate use an alignment card Reposition PS if neces sary If your OPA SOOCF system is set up for ps operation convert it for fs oper ation before continuing Follow the conversion instructions at the end of this chapter White Light Generation l 4 4 Place beam blocks such as business cards before telescopes T and T
102. responds to the label number listed on the previous page Table 2 1 Label Translations Label French German Spanish Dutch Non Attention Rayonnement Vorsicht beim Offnen Aus Peligro Cuando se abre Gevaar zichtbare en niet Interlocked Laser Visible et Invisible en tritt von sichtbare und existe Radiacion Laser Vis zichtbare laser straling Label Cas D Ouverture Exposi unsichtbare Laserstrahl ble e Invisible Evite que wanneer geoend vermijd 1 tion Engereuse de LOeil ung Bestrahlung von Auge los ojos y la piel queden blootsteling aan huid of ou de la Peau au Rayonne oder Haut durch direkte expuestos tanto a la oog aan disecte straling of ment Direct ou Diffus oder Streustrahlung ver radaicion directa como ala weerkaatsingen meiden dispersa Aperture Ouverture Laser Exposi Austritt von sichtbarer und Por esta abertura se emite Vanuit dit apertuur wordt Label tion Dangereuse Un Ray unsictbarer Laserstrahl radiacion laser visible e zichtbare en niet zichtbare 2 onnement laser visible et ung nicht dem Strahl aus invisible evite la exposi laser straling geemiteerd invisible est emis par cette setzen cion vermijd blootstellilng ouverture CDRH Rayonnement Laser visible Sichtbare und oder unsich Radiacion Laser visible y o Zichtbare en niet zichtbare European et invisible Expostion dan tbare Laserstrahlung invisible Evite que los ojos laserstraling Vermijd bloot Safety gereuse de l oeil ou de la Bes
103. rizers with mounts e dichroic set of 3 mirrors and 2 mounts for HGI e 2 dichroic sets of 3 mirrors and 2 mounts for HGII e a focus lens assembly e acollimating lens assembly e 2 crystal angle tuning mounts SFM Sum Frequency Mixing 0 0 0 1 4 Generates high energy visible output from 480 nm to 600 nm by sum fre quency mixing the residual pump and signal and idler The SFM option includes e 2 crystals or extra crystal if the HGI II option is included e 3 dichroic mirrors and 2 mounts e acrystal angle tuning mount Introduction DFM Difference Frequency Mixing Q Further extends wavelength coverage from 3 0 um to more than 10 um via difference frequency mixing of the signal and idler The output has gt 100 1 spectral purity The DFM option includes e acrystal e along pass filter with mount e a focus lens assembly e acollimation lens e acrystal angle tuning mount OPA 800C Ultrafast Optical Parametric Amplifier Chapter 2 Danger W Danger Laser Radiation Laser Safety The OPA 800C Spitfire or Hurricane regenerative amplifier Merlin or Evolution pump laser Mai Tai or Tsunami Ti sapphire oscillator and BeamLok or Millennia pump lasers are Class IV High Power lasers or laser products that have output beams that are by definition safety and fire hazards Take precautions to prevent exposure to direct and reflected beams Even diffuse or specular reflections can cau
104. rystal First block the OPA pump beam then safely fold down the D mirror Remove either the lower mirror or the whole PS mount In the OPA SOOCF a 0 5 mm thick type I FHG BBO crystal used in the HG options is used to mix the idler beam with the residual pump beam and a 0 5 mm thick type II crystal is used to mix the signal beam with the residual pump beam For the OPA SOOCP the SFM option uses the same 3 mm thick type I FHG crystal from the HGII option to mix the idler with the residual pump and a 3 mm thick type If BBO crystal is used for mixing the signal with the residual pump The optical beam path is shown in Fig ure 7 7 In order to have the signal or the idler mixed with the residual pump beam remove the PS from the beam path and after blocking the OPA pump beam safely fold down the D mirror The two lenses should not be used in either the fs or ps OPA remove them if they are present Place the SFM crystal at the SHG crystal position Both SEM crystals must be mounted so that they can be tuned about a vertical axis at the same location using the same type mount Output power is best optimized by tuning the crystal to the phase matching angle ensuring all the colors are propagating collinearly and optimizing DELAY 2 OsFM Op Os O Op Os 0 DDM1 2 3 Dichroic Mirrors OSFM Figure 7 7 Schematic layout of the SFM of the signal idler with the residual pump OPA 800C Options O O S 3 ne AT KN A E al
105. s Tsunami Millennia or BeamLok and Merlin Spitfire Hurricane system 2 All wavelength extension options are located within the OPA 800CP housing 3 The energy specifications are for an OPA 800CP 1 the 1 mJ pumped OPA Specifications apply to operation at wavelength noted gt pulse to pulse stability OPA 800C Ultrafast Optical Parametric Amplifier Outline Drawings inches All dimensions in cm Input Side View Figure 3 13 The OPA 800C Outline Drawing 3 18 Chapter 4 OPA 800CF Installation and Alignment The Spectra Physics OPA SOOCF fs optical parametric amplifier OPA is designed to deliver high energy near transform limited fs pulses with wavelengths ranging from lt 300 nm to gt 10 um The optical layout is very similar to that in the ps OPA SOOCP and this fs unit can be easily converted to a ps unit and vice versa This chapter will guide you through the installa tion and alignment of your OPA SOOCF If you have a ps system please refer to Chapter 5 Refer to Figure 4 1 while performing the following pro cedures Danger Safety eyewear should be worn throughout this procedure Laser Radiation Note Refer to your Spitfire or Hurricane user s manual for proper installa tion of the amplifier system Proper installation is essential for optimal OPA SOOCF performance Required Equipment The following equipment will help you properly align your fs OPA 800CF e Laser goggles that protect a
106. s Adjusting the Tsunami output wavelength slightly might also help stabilize the system 5 9 OPA 800C Ultrafast Optical Parametric Amplifier For ps wavelength tuning and options refer to Chapter 6 Converting from fs to ps Operation A fs OPA SOOCF uses the same base plate as a ps OPA SOOCP and can be converted from fs to ps operation and back again in the field If this is a fs ps OPA SOOCFP configured for fs operation use the following procedure to convert it to a ps configuration The ps OPA SOOCFP requires a 4 R beam splitter at BS and a thin film cube polarizer It also requires an 8 mm BBO crystal Note If this is a fs only OPA SOOCF and not a fs ps OPA SOOCFP do not make the following changes A conversion is not necessary 1 Rotate waveplate WP to minimize the WL pump beam energy 2 Block the OPA SOOCP incoming Spitfire Hurricane pump beam 3 Convert the Spitfire Hurricane for ps operation 22 cm 1 0 mJ per pulse at 800 nm lt 1 5 ps Close irises and I 5 Exchange the fs WLP sapphire plate with the ps WLP by flipping the mount 6 Replace the fs 3 mm OPA BBO crystal with the 8 mm ps OPA BBO crystal as shown in Figure 5 6 Clamping screw Top holder 2 piece spring loaded Yoke opening m pay Inner side Yoke and crystal Yoke opening E gt Bottom holder ps Crystal with Holder fs Crystal with Holder Figure 5 6 The ps and fs crystal holders mount by a spring loaded mechanism t
107. s placed in the beam about 13 cm after this lens A fused silica lens Lys 1s mounted in the beam path about 41 cm away from the crystal to collimate both the fundamental and its second harmonic In most circumstances you might not need to use these two lenses in order to get better second and fourth harmonic generation output energy and mode for of the idler espe cially if the curved mirror is placed at the WLR position as shown in Figure 4 1 A cube polarizer P is mounted after the lens as shown in Figure 7 1 to separate the SHG from the idler This polarizer allows a horizontally polarized beam to pass through 1 e the marked line should be horizontal The separated SHG of the idler exits the chassis through the exit port as shown in outline drawing Figure 3 13 The OPA SOOCP uses a 6 mm thick type I BBO crystal whereas the OPA SOOCF uses a 0 7 mm thick crystal Install the crystal in a mount that allows it to be rotated about a vertical axis as shown in Figure 7 4 a the micrometer should be horizontal The SHG of the idler is optimized for best output power by rotating the crystal to the phase matching angle and optimizing the delays The generated second harmonic is horizontally polarized for both the OPA SOOCF and OPA SOOCP For the fourth harmonic generation FHG of the idler a second 4mm thick type I BBO crystal is used in the OPA 800CP and a 0 5 mm thick crystal is used in the OPA SOOCF This FHG crystal is placed in the
108. s OPA 800C system are shown in Figure 3 3 The system includes in addition to the OPA 800C a BeamLok argon ion or Millennia diode pumped laser a Tsunami or Mai Tai mode locked Ti sapphire laser and a Spitfire or Hurricane regenerative Ti sapphire amplifier Spitfire is pumped by either a Merlin intracavity doubled Nd YLF laser or an Evolution diode pumped solid state laser Hurricane contains a diode pumped cw source a mode locked Ti sapphire laser and an Evolution For your convenience in setting up your system the OPA 800C has two pump input ports from which to choose Both ports Figure 3 9 can be configured to split the incoming pump beam part of which is used by the OPA with the remaining directed out a port directly opposite the alternative input port A type II angle tuned Beta Barium Borate BBO crystal is used as the nonlinear gain medium in the Spectra Physics OPA 800C For the type II phase matching process the signal beam is of opposite polarization to that of the pump and idler beams This makes wavelength separation of the sig nal and idler beams straightforward using polarization sensitive optics Figure 3 4 shows the typical dependence of the signal and idler wave lengths upon phase matching conditions usually the crystal angle for a type I and a type II process Unlike the type I phase matching process that normally exhibits very large phase matching bandwidths near degeneracy 3 5 OPA 800C Ultraf
109. s be able to find the power ampli fication by adjusting DELAY 2 Otherwise repeat Step 15 under White Light Generation 17 Block the WL seed and verify output from the OPA is significantly reduced If this is not the case de focus both pump beams by gradually bringing L L closer to L Ls For wavelength tuning and options refer to Chapter 6 Operation For converting back to ps operation see Chapter 5 Converting from ps to fs Operation The OPA SOOCP uses the same base plate as the fs OPA SOOCF and with the right components can be converted from ps to fs operation and back again in the field 4 8 Note a If yours is a ps only OPA SOOCP and not a fs ps OPA SOOCFP do not make the following changes A conversion is not necessary Rotate the waveplate WP to minimize the white light pump energy Block the OPA SOOCF incoming pump beam from the Spitfire Hurri cane amplifier Close irises l and l Set the Spitfire Hurricane amplifier for fs operating specifications according to its user s manual A Caution U OPA 800CF Installation and Alignment 5 Exchange the ps 8 mm WLP with the fs 3 mm sapphire plate by flip ping the mount 6 Change the second lens L in the power amplifier beam path to one with a focal length of 75 mm 7 Move the L lens to the threaded hole that is closest to Ly as shown in Figure 4 4 8 Move the L lens closer to L by 6 3 mm Figure 4 4 shows how to ch
110. s not return to the BBO crystal reinstall the whole grating assembly so that it does If you move the grating assembly you might have to iterate Steps 3 6 to place the diffracted beam back into a single vertical plane and so that it reflects back to the outer half of the BBO crystal Move the grating mount to the lower 8 32 threaded holes in the mirror mount mounting plate Adjust the grating angle micrometer so that it reflects the WL back onto the outer half of the BBO crystal In the event you need to realign the grating relative to the 1 in optic mount perform the following Otherwise skip to the next section 9 10 11 12 Verify the WL beam is parallel to the base and or optic table Loosen the 1 in grating mount and rotate it 90 to that shown in Figure 5 5 then mount the 1 in grating using the lower 8 32 hole of the grat ing mount The diffracted WL should be parallel to the base plate Loosen the set screw holding the grating optic in place and rotate the grating optic until the diffracted stripe is exactly parallel to the base plate and or table then tighten the set screw Remove the 1 in grating mount again and rotate it 90 and remount it in the lower 8 32 hole as it was before shown in Figure 5 5 Power Amplification Stage 5 8 l Ze Block the pre amplifier beam just before L To keep from damaging the BBO crystal and all the optics downstream de focus the power amplifier beam by
111. s that emit high power laser radiation Bypassing the safety interlock shutters on these systems can lead to exposure to hazardous radiation Always wear proper eye protection and follow the safety precautions in Chapter 2 Laser Safety For safety always close the pump laser shutter when you change optics Remove clean and install mirrors one at a time in sequence to avoid acci dental exchanges and loss of alignment reference After cleaning and replacing each mirror open the pump laser shutter and adjust the mirror vertically and horizontally for maximum output power Clean all optics except for the BBO crystal and grating if present Clean the crystal only when absolutely necessary and only with toluene or xylene Do not clean the grating with anything but puffs of air All mirrors are captured and held in place by a set screw Unscrew the set screw and the mirror will come out Take care not to touch the optical sur face use a piece of lens tissue to capture the optic if necessary In some cases you do not have to remove the optic from its holder to clean it Each optical element has a v shaped arrow on its outer surface This arrow points to the coated surface used to reflect the beam Also written on the barrel is the optic part number If you need to verify the location of the optic in the OPA 800C the part number for each optic is listed at the end of Chapter 9 Service and Repair If your OPA 800C becomes misa
112. se severe skin or eye damage Because the OPA 800C the Spitfire or Hurricane amplifier and the Tsu nami or Mai Tai lasers emit cw and pulsed infrared radiation they are extremely dangerous to the eye Infrared radiation passes easily through the cornea which focuses it on the retina where it can cause instanta neous permanent damage Precautions for the Safe Operation of Class IV High Power Lasers and Accessories Wear protective eye wear at all times Selection depends on the wavelength and intensity of the radiation the conditions of use and the visual function required Protective eye wear vendors are listed in the Laser Focus World Lasers and Optronics and Photonics Spectra buyer s guides Consult the ANSI and ACGIH standards listed at the end of this section for guidance Maintain a high ambient light level in the laser operation area This keeps the eyes pupils constricted thus reducing the possibility of eye damage Keep the protective cover on the OPA SOOC and the lasers at all times Avoid looking at the output beam even diffused reflections are hazard OUS Avoid wearing jewelry or other objects that may reflect or scatter the beam while using the OPA SOOC the lasers or the laser products Use an infrared detector or energy detector to verify that the laser beam is off before working in front of the OPA SOOC or the pump lasers Operate the lasers at the lowest beam intensity possible given the requiremen
113. st Optical Parametric Amplifier OR Input Alternative Input 800nm 800nm Y Periscope PS Periscope 1 PS BS Ry Al Y To A ee l2 l4 a A E Aig i Ve Power Amp Ro White Light __ __ 17 WP Generator G P BP l l i D WLR3 WLRo BBO Crystal i A A i lt EE ge Z222 1 l E A PS9 OR a fo I Y Wavelength Extension Ppuon mooo H EE INE ETO AE a Y Y Residual Optional Signal Idler Optional Pump Pump for Pump for Second OPA Second OPA BS 2 Beam Splitter lo Irises Ro 5 Reflectors for 800 nm BP Beam Protector L4 4 Lenses T4 2 Telescopes CL Collimating Lens OR1 3 Output Reflectors WLP White light Plate D4 2 4 Dichroic Mirrors P Cube Polarizer WLR4 3 White light Reflectors FL Focusing Lens PS4 2 Periscope WP M2 Waveplate G Grating Figure 5 1 Double Pass Single BBO Crystal OPA 800CP This OPA 800CP has to be pumped with an 800 nm beam from a Spit fire Hurricane amplifier with a bandwidth lt 1 3 nm lt 1 5 x trans form limited pulse duration and mJ energy per pulse The Spitfire Hurricane output spatial mode quality is critical for high OPA 800CP conversion efficiency Due to the variation of the beam size and divergence the focused and collimated beam sizes can be quite different from the factory setting Therefore while aligning an optic always protect the optics down stream especially the BBO crystal by keeping the beams at a safe intensity Do not frequently cl
114. t get the yoke and crystal turned around c Tighten the clamp by turning the screw counterclockwise until the holder assembly feels secure typically less than 1 turn Caution W If you turn the screw too far the screw will come out 10 Remove the grating mount the dashed component in Figure 4 6 from the mounting plate and fasten it into one of the 8 32 threaded holes in the middle of the base plate 11 Remove the BP see Figure 5 1 12 Install dichroic mirror D in front of WLR 13 Mount the 1 in mirror mount with a curved mirror post into the same position previously occupied by the grating 14 If this unit uses a thin film polarizer to control the white light pump energy change BS to a 1 reflection beam splitter If a cube polarizer is present you can still use the 4 R beam splitter for fs operation 4 10 This completes the ps to fs mechanical and optical conversion Continue with the Alignment section earlier in this chapter To convert your system back to ps operation please see Chapter 5 Grating Angle Micrometer a Mounting Screws 2 from this side PS Alignment Notches Vertical Adjust Grating Mount s a O Horizontal Adjust Grating Mounting Plate Figure 4 6 Conversion of the ps OPA grating assembly to the fs curved mirror Chapter 5 Danger Laser Radiation Note a OPA 800CP Installation and Alignment The Spectra Physics OPA SOOCP ps optical parametri
115. t meets the specified requirements Increase it to meet Spitfire amplifier specifications Rotate the WP to have 8 16 uJ to the WLP Correct it by steering the regen amplifier green pump beam Aperture the regen beam mode using the intracavity irises Translate the FL back and forth while changing its pump pulse duration and energy Symptom Unstable white light Possible Causes Corrective Action The pump pulse duration is incorrect The pump pulse energy is too low high The pump beam spatial mode is bad The white light plate is not at the right position or is damaged The seed wavelength has drifted Unstable pump pulse energy duration Check the pulse duration and make sure it meets required spec ifications Make sure the pump energy is between 8 and 16 uJ Vary the pump energy within 8 16 uJ while searching for stable white light Correct it by steering the green pump beam to the regenerative amplifier Aperture the regenerative amplifier beam mode using the intra Cavity irises Translate the FL back and forth and look for stable white light Shift the WLP laterally to avoid the damaged spot Adjust the seed wavelength slightly refer to your Tsunami or Mai Tai user s manual Verify pump energy stability is within 3 Make sure the pump pulse width is stable Symptom No pre amplifier amplification Possible Causes Corrective Action Beams are poorly spatially overlappe
116. table OPA output signal idler Possible Causes Corrective Action The Spitfire or Hurricane amplifier output is not stable Delay 1 Delay 2 spacing is incorrect The output wavelength is shifted or there is low pulse energy from the oscillator The white light is too strong or too weak The white light crystal is not at the focus point See Low output causes See the Spitfire or Hurricane user s manual troubleshooting section Sometimes changing the SDG switch in out by 1 2 ns will stabilize the output Adjust Delay 1 Delay 2 spacing for most stable output Adjust the seed wavelength slightly for stable output Optimizing the power of the oscillator may help Optimize the WL pump energy by optimizing WP and pulse duration Move the FL stage or the white light generation crystal to the focus point See Low output correct actions Symptom Abnormal spectrum for OPA output Possible Causes Corrective Action OPA output is not optimized The pump wavelength is not at 800 nm Spectrum is asymmetrical There are side lobes on the spectrum Notches on the spectrum Optimize the output of the OPA 800C See above Verify the pump wavelength is at 800 5 nm Optimize DELAY 2 and DELAY 1 Optimize the white light seed Optimize the overlap of the white light with the pre amplifier and power amplifier pump beam Purge the OPA to eliminate water absorption OPA 800C Ul
117. te Light GeneratlOA 225 2er es EA AE A ea 4 4 Pre ampllicatlo ne Stage aia A ee o A ae Se ee ee 4 6 Power Amplification Stage son aa si a a 4 7 Converting from ps to fs Operation o o ooooooooonrra eee tenes 4 8 Chapter 5 OPA 800CP Installation and Alignment lt lt lt 5 1 Required EGUMEN arrere ea a a e A cece 5 1 FISCA CONS a veto e aaa Ot SG a ar dia att ee A 5 1 NStallatoh 2 spas Aen eben oto Res See ete E Bees oe Mikes 5 3 AAMEN E it AA 5 4 White Light Generation ect AA cae nae x 5 4 Pre amplification Stage erroei cei eiaa a ee ee eee eee eee teen eens 5 6 Gran Sebas nabo ese wee eed Rais eer is a he Roatan e aia 5 7 Power Amplification Stage 0 0c ee eee teen eee e eee 5 8 Converting from fs to ps Operation 0 0 0 cee eee nent eens 5 10 Chapter 6 Operalloneswdacieos eur sh ceoe aaa 6 1 TUMOR Tte gt Ste oradores eos rodas hous ee eeu ee eee eee 6 1 TUMOR SY SGA arira ee ee EA AE ee ae ee ee 6 2 OPA 800CF Wavelength Selection 0 cc eee eee eee eens 6 3 OPA 800CP Wavelength Selection 0 ccc ee eee eee eee enna 6 4 Chapter 7 OPA 800C Options 0 0 0 cee ee 7 1 Harmonie Generator LODUN AGI lt td A Lees eb eee be ieee eas 7 1 Harmonic Generation Il Option HGII 2 0 0 eee ee eas 7 6 Sum Frequency Mixing Option SFM 0 0 0c eee ees 7 8 Difference Frequency Mixing Option DFM 2 0 0 ee eens 7 10 FOlANIZ ATOM Summary sal
118. the WL is still 6 3 cm parallel to the base plate before it hits grating G Use one of the alignment cards provided with this manual You may need to temporarily remove the safety cover mounted on the grating stage Translate CL to focus the WL at the BBO crystal or slightly behind it Leave it at least 2 3 mm from DELAY 1 for further optimization The WL spot on the BBO crystal should not move while varying DELAY 1 Once WL is generated you may need to repeat some steps in this section to make the WL stable and symmetrically distributed 1 e the beam should be white and green in the middle with a weak bluish ring around the outside White Light Beam Location Figure 5 4 WL beam location on the crystal in the crystal mount 5 5 OPA 800C Ultrafast Optical Parametric Amplifier Pre amplification Stage 5 6 Warning The BBO crystal can be easily damaged The pre amplifier and power amplifier 800 nm pump beams should not be focused into the crystal without careful monitoring Warning This is the pre amplification of the WL The amount of amplified WL is typically about 1 2 uJ before reaching the grating Although you can see the amplification using a photodetector will simplify this search Do not perform these steps with the power amplifier beam present nor let any beams burn ink or other material onto the surface of the BBO crystal e g do not let the beam hit your alignment card when it is close to the crystal or opti
119. the marker Also place the Leaf lens in a position so that the beam still remains on the marker and is collimated The AgGaS crystal is placed into the beam about 15 cm after lens Lys DFM crystal Filter Os 0 Les Os 0 4 Os 0 Os 0 Ler Oorm 0 0 Filters Long pass Filter Les Fused Silica Lens DFM Crystal AgGaS Lee BaF Figure 7 9 Schematic layout of the DFM option The DFM beam is separated from the signal and idler beams using a long pass filter and it exits the end panel as shown in outline drawing Figure 3 13 This filter has a unidirectional property and must be correctly installed for optimal DFM signal transmission Since signal and idler pulses must overlap temporally and spatially in the DFM process DFM pulse energy can be optimized by tuning the DFM crystal angle and adjusting both DELAY 1 and DELAY 2 for temporal overlap and by slightly adjusting steer ing mirrors R and or D in Figure 4 1 or Figure 5 1 for spatial overlap while monitoring the output power The output DFM pulse is horizontally polarized For best conversion effi ciency and spectral preservation use a thicker AgGaS crystal for the OPA SOOCP DFM option and a thinner 1 mm one for the OPA 800CF DFM option The mechanical optical layout is shown in Figure 7 10 OPA 800C Options K WN A i ON i X gt A Ze sa Ss OP amp Ll 0 Bl PD i e K i ad Sy KC Ly RY X O N N
120. to pulse stability 3 16 Table 3 3 Specifications of OPA 800CF Wavelength Extension Options Description Option Wavelength Range Pulse Energy Pulse Width Energy Stability o a HGI HGII 20 HGI HGII 247 HGI HGII 44 HGII 4a SFM Q Q SFM Q Q DFM Q Q 1 6 um to 3 0 um 1 1 um to 1 6 um 800 nm to 1 2 um 580 nm to 800 nm 400 nm to 600 nm 300 nm to 400 nm 480 nm to 533 nm 533 nm to 600 nm 3 0 um to 10 um 35 uJ at 2 0 um 75 ud at 1 3 um 10 uJ at 900 nm 15 uJ at 650 nm 3 uJ at 450 nm 3 uJ at 330 nm 30 uJ at 500 nm 20 uJ at 560 nm 3 uJ at 4 0 um lt 130 fs lt 130 fs lt 130 fs lt 130 fs lt 200 fs lt 130 fs lt 130 fs lt 3 lt 3 lt 5 lt 5 lt 7 5 lt 7 5 lt 5 lt 5 lt 5 l Due to our continuous product improvement specifications are subject to change without notice and only apply when the OPA 800CF is pumped by Spectra Physics Tsunami Millennia or BeamLok and Merlin Spitfire Hurricane system All specifications are based on a I mJ 800 nm lt 130 fs pump pulse from the Spectra Physics Spitfire Hurricane All wavelength extension options are located within the OPA 800CF housing 3 The energy specifications are for an OPA 800CF 1 the 1 mJ pumped OPA For OPA 800CF 0 5 0 5 mJ pumped OPA the output energy is 40 of the corresponding energy on the table For OPA 800CF 0 3 0 3 mJ pumped OPA the out put energy is 25 of the corresponding e
121. trafast Optical Parametric Amplifier Symptom Bad output beam quality Possible Causes Corrective Action There is a bad OPA pump beam The power amplifier pump beam size is too large or too small Damaged optics Damaged BBO crystal Conversion efficiency is too high Optimize the quality of the Spitfire or Hurricane amplifier output beam Optimize the pre amplifier or power amplifier pump beam size at the BBO crystal Replace the damaged optics Replace the damaged crystal or shift the crystal to a good spot Reduce the focus of both pump beams by adjusting L and Ly Symptom Lower output or bad beam quality with the HG SFM option installed Possible Causes Corrective Action The output beam is too large The output beam is too small The pulse duration is incorrect The crystal orientation is incorrect The beams are not temporally overlapped The beams are not spatially overlapped Lenses are still installed Polarizers are still installed Output energy is too high Optimize the pre and power amplifier pump beam size by slightly adjusting L and or L4 Use the collimation lenses for HG of the idler beam Don t use collimation lenses in the signal HG and SFM options Optimize the power amplifier pump beam size by slightly adjusting L4 Use the Spitfire or Hurricane controller to optimize the OPA pump pulse duration Verify the correct crystal is installed in the OPA
122. trahlung von Aude oder y la piel queden expuestos stelling van huid of oog Class 4 peau au Rayonnement Haut durch direkte oder tanto a la Radaicion aan directe straling of 4 5 direct ou diffus Laser de Streustrahlung vermeiden derecta como a la dis weerkaatsingen Klasse 4 classe 4 Laserclasse 4 persa Producto Laser Clase 4 Laser Produk 2 5 OPA 800C Ultrafast Optical Parametric Amplifier CE Declaration of Conformity We Spectra Physics Inc Industrial and Scientific Lasers 1330 Terra Bella Avenue P O Box 7013 Mountain View CA 94039 7013 United States of America declare under sole responsibility that the OPA 800C Optical Parametric Amplifier and Harmonic Generator meet the intent of Directive 89 336 EEC for Electromagnetic Compatibil ity Compliance was demonstrated Class A to the following specifica tions as listed in the official Journal of the European Communities EN 50081 2 1993 Emissions EN55011 Class A Radiated EN55011 Class A Conducted EN 50082 1 1992 Immunity IEC 801 2 Electrostatic Discharge IEC 801 3 RF Radiated IEC 801 4 Fast Transients and that the OPA 800C Optical Parametric Amplifier and Harmonic Generator also meet the intent of Directive 73 23 EEC the Low Voltage Directive Compliance was demonstrated to the following specifications as listed in the official Journal of the European Communities EN 61010 1 1993 Safety Requirements for Electrical Equipment
123. translating L closer to L4 Place a white business card in front of Re Verify the power amplifier beam is collimated between R and Rs Lower the Spitfire Hurricane amplifier output by changing the switch out time in the Spitfire Hurricane Synchronization and Delay Genera tor SDG for 100 ns see your Spitfire Hurricane user s manual and let the small energy beam hit R and D and the BBO crystal Note A 10 11 12 13 14 15 16 17 18 19 20 OPA 800CP Installation and Alignment Align the power amplifier beam to the BBO crystal using R and D so that it propagates collinearly with the zero order diffracted reflected WL from the grating Use a white card to block the power amplifier beam in front of L Set the D of the Spitfire Hurricane SDG back to its normal position for the specified output energy level Remove the white card from in front of Rs and place it in front of OR Remove the card from in front of L to see whether 1t generates OPG WL through the BBO crystal before it reaches OR then replace the card quickly once a determination has been made Adjust L until it generates some OPG in front of OR then remove the card from the front of L Adjust R and D so that the power amplifier beam remains collinear with the WL beam from G and is not clipped by the BBO crystal D or D and that it hits OR The two beams are collinear when the colored spots of the output
124. ts of the application Expand the beam whenever possible to reduce beam power density 2 1 OPA 800C Ultrafast Optical Parametric Amplifier Caution W 2 2 e Avoid blocking the output beam or its reflection with any part of your body e Establish a controlled access area for laser operation Limit access to those trained in the principles of laser safety e Post prominent warning signs near the laser operation area Figure 2 1 e Set up experiments so the laser beam is either above or below eye level e Provide enclosures for beam paths whenever possible e Set up shields to prevent specular reflections e Set up an energy absorbing target to capture the laser beam preventing unnecessary reflections or scattering Figure 2 2 INVISIBLE AND OR VISIBLE LASER RADIATION VISIBLE AND OR INVISIBLE AVOID EYE OR SKIN EXPOSURE TO LASER RADIATION DIRECT OR SCATTERED RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR E oe POWER WAVELENGTH S AND POWER WAVELENGTH S AND PULSE WIDTH PULSE WIDTH DEPEND ON PUMP DEPEND ON PUMP OPTIONS AND LASER OPTIONS AND LASER CONFIGURATION CONFIGURATION MANUAL CLASS IV LASER PRODUCT SEE MANUAL 0451 8080 Figure 2 1 These CE and CDRH standard safety warning labels would be appropriate for use as entry warning signs EN 60825 1 ANSI 4 3 10 1 Figure 2 2 Folded Metal Beam Target Use of controls or adjustments or the performance of procedures other than those specified herein may r
125. umber AgGas DFM Option 0452 9892 BBO Crystal Coated with mount BBO xtal 0454 0860 glued assy 0451 5121 BBO Crystal HGI 4 mm HG BBO 0452 9901 BBO Crystal HGI 6 mm HG BBO 0452 9902 BBO Crystal HGII 3 mm HGII BBO 0452 9900 BBO II SFM 3 mm SFM Option 0452 9920 Beam Splitter BS G0020 031 Beam Splitter BS 0450 9840 0450 9850 Beam Splitter OPA 800C dual assy G0501 002 Dichroic 1 D Do Dy G0501 001 Dichroic 2 PS G0502 001 Dichroic Mirrors DDM 480 600 nm SFM DDM _3 G0020 036 Dichroic Mirrors 300 360 nm HGIl G0020 035 Dichroic Mirrors 360 400 nm HGIl 3827 1547 Dichroic Mirrors 400 600 nm HGI G0020 036 Grating 600 G mm G 3828 0635 High Damage Mirror 800 nm Ra 3827 1552 Lens BaF FL 250 mm Option HG DFM 3827 1544 Lens Fused Silica FL 350 250 mm Options HG DFM 3827 1687 3827 1543 Lens Opt PLN CNV Lo La 3827 1532 Lens Opt PLN CNX L4 3827 1651 Lens Opt PLN CNX La 3827 1535 Lens Opt PLN CVX CL 3827 1534 Lens Opt PLN CVX FL 3827 1643 Long pass Filter DFM 2702 0271 Mirror Opt 25 4D x 6T Plano Silver Mirror 3827 1581 Mirror Opt 1 in x 0 25 tk Plano Gold Mirror 3827 1739 Polarizer cube Apt 8 mm or Polarizer thin film P 3828 0613 Reflector 720 860 nm R Ro R3 G0382 016 W P 1 20 Ord Retarder WP 3827 1520 White Light Plate WLP 3828 0634 OPA 800C Ultrafast Optical Parametric Amplifier Replacement Parts Diagram OPA 800CP Input Alternative Input 800nm
126. urbed between operation sessions little adjustment is required to optimize the OPA 800C performance To use either the signal or idler beam simply tune for the desired wavelength then adjust the delays for optimum output power For the OPA SOOCF optimum output in the 1 1 to 1 15 um range is obtained by removing the D optic and using the signal beam to seed the system For highest output power and stability from the OPA SOOCP at sig nal wavelength lt 1 2 um use the signal beam to seed by tuning the grating to the proper angle as described in OPA 800CP Wavelength Selection later in this chapter If you are operating the OPA SOOCP at the first order idler seeded wave length but second order signal seeded wavelength at the degeneracy point such as A 1 2 um A 2 4 um with 800 nm pump to get stable output when using fs pulses to seed the Ti sapphire amplifier overlapped order shift the pump wavelength by 2 to 3 nm by slightly rotating the Spitfire Hurricane stretcher and compressor gratings The following procedures show how to perform a typical turn on and turn off of the OPA SOOC system and how to select output wavelengths Turning On the System 1 Turn off OUTPUT ENABLE on the Spitfire or Hurricane Synchroniza tion and Delay Generator SDG controller 2 Turn on the Tsunami pump source or the Mai Tai and verify it is set to its required power level Let it warm up and stabilize typically 15 30 minutes depending on labo
127. ut power Optimize the Spitfire Hurricane compression delay stage for optimum OPA 800C output power and compare this power to specified power If the laboratory environment is the same as it was the last time the OPA was used OPA performance now should be similar to what it was then and little optimization should be required Adjusting DELAY 1 and DELAY 2 may change the wavelength slightly Turning Off the System 6 2 l Turn off the Spitfire or Hurricane SDG OUTPUT ENABLE Close the Merlin or Evolution shutter then shut off its LAMP ENABLE Turn off the Merlin pump laser or the Evolution according to its user s manual Turn off the Tsunami pump laser or the Mai Tai according to its user s manual Operation OPA 800CF Wavelength Selection To monitor the spectrum of the OPA 800CF output for the signal beam we suggest using a monochromator with a CCD detector for example a ger manium based Electrophysics 7290 as shown in Figure 6 2 In addition an infrared viewer or card beam splitter and suitable attenuator will be needed for the following procedure 1 Using either an ir card beam splitter and suitable attenuator or a sil ver mirror and the visible light in the beam pick off some or all of the OPA SOOCF output beam attenuate it 1f necessary and center it on the input slit of the monochromator 2 Set the monochromator wavelength to the desired OPA SOOCF opera tion wavelength E CCD Camera M
128. ved and access to the beam is required take care to block any stray reflections Maintenance Required to Keep this Laser Product in Compliance with the Center for Devices and Radiological Health CDRH Regulations This section presents the maintenance required to keep this laser accessory product in compliance with CDRH Regulations This laser accessory product complies with Title 21 of the United States Code of Federal Regulations chapter 1 subchapter J parts 1040 10 and 1040 11 as applicable To maintain compliance with these regulations once a year or whenever the product has been subjected to adverse envi ronmental conditions e g fire flood mechanical shock spilled solvent etc check to see that all features of the product identified below function properly Also make sure that all warning labels remain firmly attached refer to the CDRH CE drawing later in this chapter 1 Verify that removing the remote interlock plug on the pump laser pre vents laser operation 2 Verify the laser system will only operate when the pump laser s inter lock key switch is in the on position and that the key can only be removed when the switch is in the off position 3 Verify the emission indicator on the pump laser works properly that is it emits a visible signal whenever the laser 1s on 4 Verify that the time delay between turn on of the pump laser emission indicator and the starting of that laser gives you enoug
129. your convenience spectral bandwidth in nm versus wavenumber for 25 cm at different wavelengths is listed in Table A 2 l A 3 OPA 800C Ultrafast Optical Parametric Amplifier Table A 2 Corresponding bandwidth in nm of 25 cm spectrum at different wavelengths A nm AA nm A um AA nm A um AA nm 300 0 23 1 1 3 0 3 0 23 325 0 26 1 2 3 6 3 5 31 400 0 40 1 3 4 2 4 0 40 450 0 51 1 4 4 9 4 5 51 500 0 63 1 5 5 6 5 0 63 550 0 76 1 6 6 4 5 5 76 560 0 78 1 7 7 2 6 0 90 600 0 90 1 8 8 1 6 5 106 650 1 06 1 9 9 0 7 0 123 700 1 23 2 0 10 0 7 5 141 750 1 41 2 1 11 0 8 0 160 800 1 60 2 2 12 1 8 5 181 850 1 81 2 3 13 2 9 0 203 900 2 03 2 4 14 4 9 5 226 950 2 26 2 5 15 6 10 0 250 1000 2 50 2 6 16 9 1050 2 76 2 7 18 2 2 8 19 6 2 9 21 0 3 0 22 5 A 4 Appendix B OPA 800C Wavelength Tables The following tables are provided for your convenience They show the corresponding signal and idler output wavelengths for fs and ps OPAs at the given pump wavelength Table B 1 shows the corresponding values at 800 nm the pump wavelength specified for this system and at which the system is tested in the factory The other tables show corresponding output for pump wavelengths other than 800 nm These input wavelengths are not specified or guaranteed because the crystal cut phase matching may not be appropriate at these wavelengths However these values are typical and are listed in the event you want to operate the OPA

OPA-800C - Spectra

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