Laser Flash Lamp

Laser Flash Lamps or Gas discharge laser lamps are routinely used as optical pump sources for solid state lasers. The two main categories of laser pump lamps are DC arc lamps for continuous pumping, and laser flash lamps for pulsed pumping. Both offer high brightness, high power capability, long operating life, and low cost per hour of operation.

How They Work

An electric current is discharged through a gas-filled quartz tube, generating a hot plasma. This plasma radiates intense light which can be coupled into a laser crystal, optically exciting the laser medium. For Nd:YAG lasers, lamps filled with the noble gases Xenon and Krypton are frequently selected as they are most efficient at radiating wavelengths of light which are in the excitation spectrum of the Nd atoms and are readily absorbed by the Nd:YAG crystal. Flashlamps are operated in a pulsed mode; they discharge high current pulses (hundreds of amps) ranging in duration from .1 to 20.0 milliseconds. They are filled with either Krypton or Xenon: Krypton is more efficient at low currents and Xenon at high currents. Fill pressures are usually less than one atmosphere to help prevent explosions during the highly energetic current pulses. Laser Flash Lamp At low power densities, Krypton filled lamps generate a spectral output that is efficiently matched to the Nd:YAG absorption spectrum. At higher power densities, Xenon becomes the more efficient fill gas. Traditionally, a Pulse Forming Network (PFN) of capacitors and inductors is used to generate the high current discharge. The PFN circuit is designed to match impedance with the flashlamp. The capacitors, (or capacitor bank) in series with the inductor(s) are charged and held across the map terminals. The impedance of the lamp prevents discharge until the lamp is ionized by the trigger pulse. The capacitor then discharges through the inductor and the lamp, generating a pulse of current and a burst of light. The capacitors can be charged and discharged repeatedly at high repetition rates to generate a steady stream of laser pulses. For improved reliability, stability and lamp lifetimes, a “simmer” process is employed. After the lamp is triggered, and between the subsequent current pulses, a steady DC current (typically .1-2.0 amps) is established and maintained by a separate power supply. The PFN is held off from discharging by SCR’s. A rate generator trips the SCR’s at the desired rate allowing the PFN to discharge through the lamp. Simmering eliminates the need to trigger the lamp for each pulse. This greatly improves pulse-to-pulse reliability and stability and also extends the life of the flashlamp. In recent years, solid state switching power supplies have begun replacing capacitor/inductor PFN’s in flashlamp pumped Nd:YAG lasers. Instead of charging and discharging a PFN, modern switching power supplies directly generate the current pulse. While PFN’s generate pulses which are shaped like half sine waves, switching power supplies can generate current pulses in a number of useful shapes: square waves, stepped, etc. The ability to shape the current pulse, and thus the laser pulse, has led to great improvements in Nd:YAG laser material processing.

CW arclamps

CW arclamps

Flashlamps

Laser Flash Lamp
DC Arclamps are operated in a continuous wave (CW) mode and discharge a constant current in the 10-40 Amp range between 100-250 Volts. The continuous light radiated induces constant gain in the Nd:YAG rod, generating a continuous laser beam. Krypton gas is almost always selected for CW applications because it is more efficient than Xenon at these power levels; in fact, these lamps are universally known as Krypton arclamps. For increased efficiency, they are filled to very high pressures, typically 5-10 atmospheres. Violent explosions can result from mishandling, so safety glasses should be worn during handling and installation. These high pressures make Krypton arclamps difficult to start because of their high impedance. Therefore, fairly complex starting circuitry must be employed: first, a short duration (approximately one microsecond) high voltage (20-30kv) trigger pulse is applied to the lamp, which causes an initial ionization of the gas. Next, a boost circuit drives a low current through the lamp at moderate voltage for a few milliseconds after which the main power supply can take over and run the lamp at its normal operating current and voltage (typically 20 amps at 150 Volts).

Manufacturing Highlights

Tubing, Electrodes, Quartz to Metal Sealing, Gas Filling, Connectors, TestingExtremely tight quality control and anti- contamination procedures must be adhered to in the laser lamp manufacturing process.

 

Lamp envelopes are made from high quality quartz tubing. Naturally fused silica quartz is most commonly used, however, some solid state laser materials are excited by deep ultraviolet radiation, filtered by natural quartz. For these lasers, synthetic quartz tubing, which transmits deeper into the UV, is used. Nd:YAG lasers, on the other hand, are made from quartz tubing doped with cerium or titanium, which filter more UV than natural quartz. Arclamps usually employ thinner walled tubing (typically 0.5mm) for better heat transfer to the cooling fluid. Sometimes different sized tubes are fused together to create a lamp envelope with enhanced performance characteristics.

Electrodes

Anodes, the positive electrodes, are made from easily machinable thoriated tungsten which has an excellent ability to handle the thermal load created by receiving electrons from the current discharge. Cathodes, the negative electrodes, are some- times made from thoriated tungsten, however, for the cathode’s strenuous task of emitting electrons into the gas discharge, improved designs have been developed. For example, most laser lamp cathodes now incorporate chemically impregnated tips which reduce the work function at the cathode surface and subsequently reduce cathode “sputtering,” the major cause of lamp aging and failure. This chemical mixture generally contains barium, calcium and alumina; each lamp manufacturer has their own proprietary chemical recipe. These chemically impregnated cathodes require more difficult, higher temperature processing, but their higher cost is offset by longer lamp lifetimes. Since anodes are designed to receive electrons efficiently and cathodes are designed to emit the same, it is very important to install lamps in the proper polarity direction.

Chemically impregnated cathode tips

Laser Flash LampsInstalling a lamp backwards will lead to premature lamp failure due to electrode degradation. The anode end of a lamp is marked with a red color code or a “+” sign and should be attached to the positive connection. The cathode is usually unmarked and should be attached to the negative terminal.

Quartz to Metal Sealing

Quartz and tungsten have very different coef- ficients of thermal expansion, and cannot be directly fused because the difference would lead to strain and cracking failure. Inter- mediate joining materials are required to overcome this dilemma. Early lamp designs incorporated a soft solder quartz-to-metal joint which has the advantage of being thermally and mechanically rugged in operation. The process is fairly easily automated for repeatability, however, the solders used cannot tolerate the high temperature processing used to manufacture

Glassblower constructing a graded seal

Laser Flash Lampmodern chemically impregnated cathodes. To overcome this limitation, “graded glass” seal technology was developed: a glass with a coefficient of thermal expansion in between that of quartz and tungsten is used to join the two dissimilar materials. The glass has a very high melting point so it can tolerate high temperature cathode processing easily but it is more fragile than traditional solder seal and cannot tolerate much mechanical strain. Furthermore, this type of seal does not easily lend itself to automation: skilled glassblowers individually hand craft graded glass seal lamps.

Gas Filling

After the electrodes have been inspected and sealed into the quartz envelope, the lamps are processed in batches on multiport vacuum/gas- filling stations. The lamps are pumped down to a very high vacuum and processed at high temperatures using hydrogen torches and RF induction coils, driving any contaminant gases out of the lamp. They are then filled to the specified fill pressure with either Xenon or Krypton.

Lamps at a gas filling station

Laser Flash Lamp The electrical characteristics of each lamp are then checked to ensure that the lamps have been properly processed. After passing electrical inspection, the lamps are ready to have end connectors attached.

Connectors

Lamps can be terminated with many different styles of connectors, depending on the laser system designer’s preference. The critical consideration is making sure the lamp can be installed in the laser head easily and without straining the glass-to-metal seals. Many different schemes have been developed to achieve this, including solid metal cylindrical lugs which can clip into spring fittings in the laser head. Flexible leadwires are another popular design. Some lamps connectors have built-in O-Ring grooves and others use a combination of flexible leadwires and solid terminal lugs for good strain relief and positive electrical connection.

Laser Flash Lamp and Laser Arc Lamp Cross Reference Guide

DESCRIPTION MANUFACTURER DLI PART NO.
APOLLO
FLASH LAMP APOLLO 1610 LMP-10014
FLASH LAMP APOLLO 1630 LMP-10079
AB/BAASEL
FLASH LAMP AB/BAASEL/LPKF LMP-12464
FLASH LAMP AB/BAASEL/LPKF, CDQ LMP-12505
CANDELA
FLASH LAMP CANDELA, SPTL LMP-12528
FLASH LAMP CANDELA LASER #9906-CN-27-7 LMP-13854
CELL ROBOTICS
FLASH LAMP CELL ROBOTICS CUSTOM LMP-12520
COHERENT
FLASH LAMP COHERENT M34, KRYPTON LMP-11097
FLASH LAMP COHERENT M34, P1165 LMP-11762
FLASH LAMP COHERENT MEDICAL, VP SELECT LMP-12529
FLASH LAMP COHERENT OMEGA LMP-10782
FLASH LAMP COHERENT 14” LMP-14793
FLASH LAMP COHERENT MODEL 11 & 14 GLASS LMP-10692
CONTROL
FLASH LAMP CONTROL 400 LMP-10013
CONVERGENT
FLASH LAMP CONVERGENT P50/AURORA LMP-12524
EKSPLA
FLASH LAMP EKSPLA LASER, P1194 LMP-13611
FLASH LAMP EKSPLA LASER, P1195 LMP-13610
ELECTROX
FLASH LAMP ELECTROX, 262-000-006 LMP-10006
FLASH LAMP ELECTROX, 5.5” ARC, 635-000-013 LMP-10004
FLASH LAMP ELECTROX, 5.5” ARC, 635-000-013, LOW IMPED LMP-11073
FLASH LAMP ELECTROX, PULSED MARKER, 262-000-003 LMP-10027
FLASH LAMP ELECTROX, PULSED, 262-000-012 LMP-10002
FLASH LAMP ELECTROX, PULSED, 262-000-019 LMP-10362
GSI LUMONICS
FLASH LAMP LUMONICS JK701, LONG PULSE LMP-11563
FLASH LAMP LUMONICS JK702, SCREENCUT LMP-12561
FLASH LAMP LUMONICS MULTIWAVE LMP-11453
FLASH LAMP LUMONICS/JK HYSERIES LMP-11287
FLASH LAMP LUMONICS/JKMS20 LMP-11201
FLASH LAMP LUMONICS/JKMS300 LMP-10007
FLASH LAMP LUMONICS/JKMS330/830 LMP-10016
FLASH LAMP LUMONICS/JKMS330/830, QARC LMP-10833
FLASH LAMP LUMONICS/JKMS35 LMP-11392
FLASH LAMP LUMONICS/JKMS701/702 LMP-10485
FLASH LAMP LUMONICS/JKMS704 LMP-11012
FLASH LAMP LUMONICS/JKMS704, SPECIAL LMP-11408
FLASH LAMP LUMONICS/JK701, HIGH ENERGY LMP-11724
FLASH LAMP LUMONICS LUXSTAR LMP-11421
FLASH LAMP LUMONICS LUXSTAR, LOW POWER LMP-12560
HOBART
FLASH LAMP HOBART, 3KW LMP-11857
HOYA
FLASH LAMP HOYA MEMORY REPAIR LMP-13975
IQL30
FLASH LAMP IQL30 LMP-12031
KORAD
FLASH LAMP KORAD KWD LMP-10026
LASAG
FLASH LAMP LASAG, 64.0153 LMP-13053
FLASH LAMP LASAG, 64.0302 LMP-10980
FLASH LAMP LASAG, 64.0308 LMP-10809
FLASH LAMP LASAG, 64.0309 LMP-11357
FLASH LAMP LASAG, 64.0323 LMP-11022
FLASH LAMP LASAG, 64.0324 LMP-10812
FLASH LAMP LASAG, 64.0371 LMP-11551
FLASH LAMP LASAG, 64.0372 LMP-11297
FLASH LAMP LASAG, 64.0372, LOW IMPEDANCE LMP-11674
FLASH LAMP LASAG, 64.0551 LMP-12264
FLASH LAMP LASAG, 64.0552 LMP-13916
FLASH LAMP LASAG, 64.0579 LMP-11918
FLASH LAMP LASAG, KOS-102 LMP-13246
LASER INDUSTRIES
FLASH LAMP LASER INDUSTRIES LMP-10635
LASERONICS
FLASH LAMP LASERONICS 4900 LMP-11632
LASERVALL
FLASH LAMP LASERVALL PL15 LMP-13295
FLASH LAMP LASERVALL PL50 LMP-13296
LEE
FLASH LAMP LEE 650M LMP-12523
LPKF
FLASH LAMP LPKF 800×800 LMP-13353
MBB
FLASH LAMP MBB ML-2 LASER LMP-12452
MLS
FLASH LAMP MLS P500F LMP-11219
NEC
FLASH LAMP NEC P2014/2019 LMP-12751
FLASH LAMP NEC YL476A LMP-11410
NIHON
FLASH LAMP NIHON LMP-16281
QUANTA RAY
FLASH LAMP QUANTA RAY DCR II, III LMP-10852
FLASH LAMP QUANTA RAY, DCR I LMP-10936
QUANTEL
FLASH LAMP QUANTEL LMP-10983
FLASH LAMP QUANTEL 581C LMP-10851
FLASH LAMP QUANTEL 611 LMP-11218
FLASH LAMP QUANTEL, 203-0019 LMP-11152
FLASH LAMP QUANTEL, 581-10 & 581-20 LMP-10068
RAYTHEON
FLASH LAMP RAYTHEON 347/384 LMP-10024
FLASH LAMP RAYTHEON 484 LMP-10029
FLASH LAMP RAYTHEON 500/550 LMP-10010
FLASH LAMP RAYTHEON 500/550, XENON LMP-10012
FLASH LAMP ASSEMBLY, RAYTHEON SS500, REBUILD LMP-14801
FLASH LAMP ASSEMBLY, RAYTHEON SS550 LMP-14767
FLASH LAMP ASSEMBLY, RAYTHEON SS550, REBUILD LMP-14800
ROFIN SINAR
FLASH LAMP ROFIN SINAR, RS500 LMP-11193
SHARPLAN
FLASH LAMP SHARPLAN 2100 LMP-11631
FLASH LAMP SHARPLAN EPILIGHT LMP-16325
SLT
FLASH LAMP SLT, CLMP LMP-12775
SPACE RAY
FLASH LAMP SPACE RAY-136, W/O TRIGGER WIRE LMP-11730
THERMOLASE
FLASH LAMP THERMOLASE SOFTLIGHT LMP-16366
TOSHIBA
FLASH LAMP TOSHIBA, 300 WATT LASER LMP-10025
FLASH LAMP TOSHIBA, LAY806 LMP-11291
FLASH LAMP TOSHIBA 150 WATT LASER LMP-10904
TRIMEDYNE
FLASH LAMP TRIMEDYNE LMP-16326
TRUMPF/HAAS
FLASH LAMP HAAS, HL703-HL3003 LMP-14527
UNITEK MIYACHI
FLASH LAMP UNITEK MIYACHI, LW10, LW15, LOW PULSE LMP-13813
FLASH LAMP UNITEK MIYACHI, LW250, LW300 LMP-12098
FLASH LAMP UNITEK MIYACHI, LW51, LW52, LW100 LMP-11643
FLASH LAMP UNITEK MIYACHI, LW50A, LW70A LMP-13052
Arc Lamps
AB/BAASEL
DESCRIPTION MANUFACTURER PART NO.
ARC LAMP AB/BAASEL 2000/6000, 20 AMP LMP-12704
ARC LAMP AB/BAASEL 2000/6000, 30 AMP LMP-13023
ARC LAMP AB/BAASEL LASER, CLC512 LMP-10495
ARC LAMP AB/BAASEL LASER, NEW STYLE LMP-11288
ARC LAMP AB/BAASEL, 145 VOLTS LMP-14406
ARC LAMP AB/BAASEL, STARMARK 150 LMP-14040
ARC LAMP AB/BAASEL LASER, 100 WATT LMP-11139
COHERENT
ARC LAMP COHERENT ANTARES LMP-11064
ARC LAMP COHERENT MARKER M815 LMP-10008
ARC LAMP COHERENT/KIGRE, MODEL 7000-9000 LMP-16327
CONTROL
ARC LAMP CONTROL 258/520 LMP-10022
ARC LAMP CONTROL 258/520, W/GOLD COATED ENDS LMP-11726
ARC LAMP CONTROL 2660 LMP-10019
ARC LAMP CONTROL 510 LMP-10021
ARC LAMP CONTROL 510 (OLD) LMP-10496
ARC LAMP CONTROL 512 LMP-10018
ARC LAMP CONTROL 612, 50 WATT LMP-11539
ARC LAMP CONTROL 632 LMP-11272
ARC LAMP CONTROL ELITE, 100 WATT LMP-10598
ARC LAMP CONTROL INSIGNA/ICON LMP-12435
ARC LAMP HIGH POWER, CONTROL 258/520 LMP-10717
COOPER
ARC LAMP COOPER 2500 LMP-14817
CRAWFORD
ARC LAMP CRAWFORD LMP-13502
ELECTROX
ARC LAMP ELECTROX, 120 WATT LMP-10001
ARC LAMP ELECTROX, DC ARC, 75 WATT LMP-10003
ARC LAMP ELECTROX, HV, 75 WATT LMP-10005
ESI
ARC LAMP ESI 3570 LMP-10015
ARC LAMP ESI 3570, LOW VOLTAGE LMP-11407
FANUC
ARC LAMP FANUC LMP-14520
FOBA
ARC LAMP FOBA, 100 WATT LMP-14366
ARC LAMP FOBA, 200 WATT LMP-14799
FUJI
ARC LAMP FUJI MARKER LMP-11420
KORAD
ARC LAMP KORAD KY3 LMP-10009
ARC LAMP KORAD KY-5 LMP-10020
LASER OPTRONICS
ARC LAMP LASER OPTRONICS, MODEL 747/757 LMP-11883
LASER PHOTONICS
ARC LAMP LASER PHOTONICS LMP-11741
ARC LAMP LASER PHOTONICS, NL504 LMP-12055
LASERTRONICS
ARC LAMP LASERTRONICS, METALASE LMP-14796
LASERVALL
ARC LAMP LASERVALL VALMARK 7 LMP-12810
LEE
ARC LAMP LEE LASER, 718 LMP-11074
ARC LAMP LEE LASER, 20A LMP-10449
ARC LAMP LEE LASER, 30A LMP-10328
ARC LAMP LEE LASER, 8250M LMP-13793
ARC LAMP LEE LASER, LOW VOLTAGE LMP-10842
LPKF
ARC LAMP LPKF, SL25 LMP-16280
MUNICH
ARC LAMP MUNICH LASER MODEL 35 LMP-11889
NEC
ARC LAMP NEC SL114 LMP-11586
ARC LAMP NEC SL115 LMP-11507
ARC LAMP NEC P2015A LMP-16302
PMI
ARC LAMP PMI, ARC, KRYPTON LMP-10531
QUANTRAD / LASERMETRICS
ARC LAMP QUANTRAD 9555 LMP-10696
ARC LAMP LASERMETRICS 95150 LMP-11717
ARC LAMP LASERMETRICS 9560 LMP-11249
QUANTRONIX
LAMP ASSEMBLY QUANTRONIX 114 LMP-10964
LAMP ASSEMBLY QUANTRONIX 116 LMP-10776
LAMP ASSEMBLY QUANTRONIX 116, LONG LIFE LMP-11416
ARC LAMP QUANTRONIX 114 LMP-10017
ARC LAMP QUANTRONIX 114, LONG LIFE LMP-11117
ARC LAMP QUANTRONIX 116 LMP-10023
ARC LAMP QUANTRONIX 116, LONG LIFE LMP-11000
ARC LAMP QUANTRONIX 117 LMP-10147
ARC LAMP QUANTRONIX 117, LONG LIFE LMP-11326
ARC LAMP QUANTRONIX 118, LONG LIFE LMP-11126
ARC LAMP QUANTRONIX DRS LMP-13535
ROFIN SINAR
ARC LAMP ROFIN SINAR, MARKER, NEW LMP-12526
ARC LAMP ROFIN SINAR, MARKER, OLD LMP-12527
SCHWARTZ
ARC LAMP SCHWARTZ LMP-13409
SLT
ARC LAMP SLT LMP-12331
SPECTRA PHYSICS
ARC LAMP SPECTRA PHYSICS, MERLIN LMP-12550
SPECTRON
ARC LAMP SPECTRON LMP-11866
ARC LAMP SPECTRON F950-4 LMP-13061
ARC LAMP SPECTRON SL502/503/902/903 LMP-13209
ARC LAMP SPECTRON, F410-4 LMP-12488
TRUMPF/HAAS
ARC LAMP HAAS, HL703-HL3003 LMP-16300
UNITEK MIYACHI
ARC LAMP UNITEK MIYACHI, LM45 LMP-13062
U.S. LASER
ARC LAMP US LASER, 500 WATT LMP-11801
ARC LAMP US LASER, 750 WATT LMP-14211