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. 
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. [one_half]
CW arclamps
Flashlamps
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
Installing 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
modern 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
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 |