激光技术及应用

激光的基础、应用及其发展LightAmplificationthroughStimulatedEmissionofRadiation引言基本原子、分子受激发射放大而产生的一种相干光辐射；极高的亮度，极好的方向性、单色性和相干性。

激光：Laser：激光的发明：1958激光名词出现

1960第一台激光器出现激光应用：光学：激光物理，非线性光学、激光光谱学等新兴学科工业：已广泛地利用激光进行切割、焊接、打孔、热处理等医学：外科手术刀，医治很多疑难病症信息：计算机、音视频显示设备等能源：激光核聚变环保：环境及污染监测军事：制导、测距、致盲和做未来高技术战争中的新武器

ArthurL.Schawlow

CharlesH.Townes

AleksandrM.Prokhorov

NicolayG.Basov

NicolaasBloembergenKaiM.Siegbahn1964年诺贝尔物理奖1981年诺贝尔物理奖激光是一种电磁波Lightisanelectromagneticwave.Differentwavelengthsinthevisiblespectrumareseenbytheeyeasdifferentcolors.lWavelengthRed:

l=700nm

Blue:

l=400nm

Laser-P

受激辐射IncidentPhotonExcitedAtomLaser-P

StimulatedPhotonsamewavelengthsamedirectioninphaseIncidentPhoton激光器的构成工作物质ACTIVEMEDIUMSolid(Crystal)GasSemiconductor(Diode)Liquid(Dye)激励系统EXCITATIONMECHANISMOpticalElectricalChemical光学谐振腔OPTICALRESONATORHRMirrorandOutputCouplerTheActiveMediumcontainsatomswhichcanemitlightbystimulatedemission.TheExcitationMechanismisasourceofenergytoexcitetheatomstotheproperenergystate.TheOpticalResonatorreflectsthelaserbeamthroughtheactivemediumforamplification.HighReflectanceMirror(HR)OutputCouplerMirror(OC)ActiveMediumOutputBeamExcitationMechanismOpticalResonatorLaser-P

HELIUM-NEONGASLASERLaser-P

CourtesyofMetrologic,Inc.固体激光SOLIDSTATELASERLaser-P

HighReflectanceMirror(HR)OutputCouplerMirror(OC)EllipticalReflectorPowerSupplySolidStateRodArcorFlashLampSingleLampDoubleLampRearMirrorAdjustmentKnobsSafetyShutterPolarizerAssembly(optional)CoolantBeamTubeAdjustmentKnobOutputMirrorBeamBeamTubeHarmonicGenerator(optional)LaserCavityPumpCavityFlashlampsNd:YAGLaserRodQ-switch(optional)CourtesyofLosAlamosNationalLaboratoryNd:YAGLASERQ-开关StoredEnergyOutputPowerTimeWithQ-SwitchWithoutQ-SwitchLasingbeginswithoutQ-switchQ-SwitchopensQ-switchedPulse:1Jin10ns->100MW

NormalLongPulse:1.0Jin1.0ms->1KW

TimeHROCAMQLaser-P

半导体激光DIODELASERLaser-P

SiO2MetallicContact10-20mmCleavedFacetCurrentDistribution+-EllipticalBeamP-NJunction激光光谱LASERSPECTRUM10-1310-1210-1110-1010-9

10-810-710-610-510-410-310-210-11

10

102

LASERS20030040050060070080090010001100120013001400150010600UltravioletVisibleNearInfraredFarInfraredGammaRaysX-RaysUltra-VisibleInfraredMicro-RadarTVRadio violet waveswaveswaveswavesWavelength(m)Wavelength(nm)Nd:YAG1064GaAs905HeNe633Ar488/515CO2

10600XeCl308KrF2482wNd:YAG532RetinalHazardRegionArF193CommunicationDiode1550Ruby694Laser-P

Alexandrite755激光的特点：高亮度、高方向性、高单色性、高的相干性Highirradiance，Beamdivergence，

Monochromaticity，

Coherence1.1激光的特性①方向性：普通光源的发光无方向性，而激光的发光可以限制在几个毫弧度立体角甚至更窄小的角度范围，这就使得在照射方向上的照度提高了4

10(3×2)

107倍。②高亮度：激光之所以有强的破坏能力是由于其本征亮度(在光照射方向)，这是激光与物质相互作用有非凡效果的决定因素。一般太阳光亮度大约是：103W／(cm2·sr)，而大功率激光器的输出亮度可达1010~1017W／(cm2·sr)，即是说可以高出7-14个量级。③单色性：由激光辐射的能量，通常集中在十分窄的光谱波段或频率范围内，一般实验室使用的光谱单色灯，单色性

／

106，而激光可高达1010~1013，因此利用现今已有的波长可调的激光装置可以做成波长分辨率极高的单色仪，可用来测量在不同条件下产生原子和分子光谱的谱线宽度。④高相干性：激光不仅具有高方向性和高单色性的特点，由激光所产生的波列还有高度的整齐的间隔和长度，这导致激光通过光学干涉仪的装置，可以使波列前后，尽管有大的光程差，仍能相干涉。

激光的应用需要的条件激光器必须满足各种应用的不同技术要求，必须高度稳定可靠，价廉物美；有各种配套支撑技术，比如探测器、光学系统、精密机械、信号处理电路和电源等。

1、已发展成规模宏大的产业，如光纤通信和光存储；2、已成为先进的生产工具，如激光加工；

3、直接造福于人类健康，如激光医疗；

4、成为新型的武器装备，如激光制导炸弹；5、探索和研究中的激光应用

激光材料加工技术分类

CategoryofLaserMaterialProcessingTechnology激光切割LaserCutting激光焊接LaserWelding激光表面处理LaserSurfaceTreatment激光微加工LaserMicromaching激光快速成型LaserAssistedRapidPrototyping材料加工激光器

LasersforMaterialProcessingCarbonDioxideLasers-CO2Nd:YAGLasersDiodeLasersFiberLasersExcimerLasersThreeprimarylasingmechanismsforCO2laserdevicescurrentlyexist:1)conventional(sealedandslowflow);2)flowing(axialandtransverse);3)diffusion(noflowwiththecoolingwallsincloseproximity).

LasersforMaterialProcessing-CO2lasers快速轴流CO2激光器

快速轴流CO2激光器是由工作气体沿放电管轴向流动来实现冷却的，且气流方向同电场方向和激光方向一致，其气流速度一般大于100m/s，有的甚至可达亚音速。其结构主要由细放电管、谐振腔、高压直流放电系统、高速风机、热交换器及气流管道等部分组成。

特点：光束质量好（基模或TEM01模）

功率密度高

电光效率高，最高可达26%；

结构紧凑

可以连续和双制运行

Typical6kWIndustrialCO2LaserLasersforMaterialProcessing-CO2lasers横向流动型CO2激光器

该激光器的工作气体沿着与光轴垂直的方向快速流过放电区以维持腔内有较低的气体温度，从而保证有高功率输出。单位有效谐振腔长度的输出激光功率达10KW/m，商用器件的最大功率可达25KW/m。但其缺点是光束质量较差，在好的情况下可以得到低阶模输出，否则为多模输出。这种类型的激光器广泛应用于材料的表面改性加工领域，如激光表面淬火、激光表面合金化、激光表面熔覆、激光表面非晶化等。

9000W横流CO2激光器（以色列）6000W横流CO2激光器（德国）YAG激光器是以钇铝石榴石晶体为基质的一种固体激光器。钇铝石榴石的化学式是Y3A15O12,简称为YAG。在YAG基质中掺入激活离子Nd3＋(约1%)就成为Nd:YAG。YAG激光器基本组成部分是激光工作物质、泵浦源和谐振腔

YAG激光器按输出波形可分为连续波YAG激光器、重频YAG激光器和脉冲激光器；按工作波长可分为1．06μmYAG激光器、倍频YAG激光器、和可调谐YAG激光器等；按泵浦方式可分为：灯泵浦和半导体激光泵浦YAG激光Nd:YAGLaser2kWLampPumpedNd:YAGlaserLasersforMaterialProcessing-YAGlasersLasersforMaterialProcessing-YAGlasersTypical4kWIndustrialNd:YAGLaserLasersforMaterialProcessing-YAGlasersDiodelasersHighPowerDirectDiodeLasers[HPDDL],LasersforMaterialProcessing-DiodelasersLasersforMaterialProcessing-Diodelasers1、Crystal2、laserbeam3、outputmirror4、diodebar5、collimation6、rearmirror7、cooling8、supplyDiodepumpedYAGLaser(Sidepumped)DiodePumpedYAGLaser(Endpumpedlaser)LasersforMaterialProcessing-DiodepumpedYAGlasersThindiscpumpedLasersforMaterialProcessing-DiodepumpedYAGlasersDiagramofsinglemodulefordisclaserLasersforMaterialProcessing-DiodepumpedYAGlasersFiberLasersThefiberlaserisnotaNd:YAGlaserthatisfiberdelivered,butratheradiode-pumped,Ytterbium-basedfiberlaserresonatorthatisfiberdelivered.OnthewholethebeamqualityandpowerarebetterthanthecurrentNd:YAGlasertechnologythatisfiberdelivered.Nolaserthathasadvancedasfastasthefiberlaser.Withinafewyearsfiberlasershaveincreasedfromwattstokilowatts!Thetelecomtechnologyprovidedasoundtechnologyforrapidscalingtoindustrialpowerlevels.Theindustrialcommunityhasbenefitedfromthetelecomslowdown.Thenewdirectionofthetelecomtechnologyhasprovidedanewandexcitinglaserthatisbenefitinglasermaterialprocessing.LasersforMaterialProcessing-FiberlasersDiagramoffiberlaser;(CourtesyIPGPhotonics)LasersforMaterialProcessing-Fiberlasers4千瓦光纤激光60x80x160cm尺寸400kg重量300M长(Ø=300mm)光纤传输光纤激光的灵活性三百米以上激光头LasersforMaterialProcessing-FiberlasersLasersforMaterialProcessing-FiberlasersLasersforMaterialProcessing-FiberlasersYb镱Er铒Tm铥PotentialandRealityofIndustrialApplicationsforFiberLasersFiberlasersofferalargespectrumofcapabilitiesenablingittobeusedinmanydifferentapplications.Someoftheindustrialapplicationswithpromisingprocessingcapabilitiesinclude:•Lasermarking-“Q”switchedfiberlasersarebeingproducedwithupto200wattsofaveragepower•Medicaldevices-Singlemodepowerproducesprecisionsmallkerfcutting•Highspeedwelding-highmulti-kilowattpowerlevelswithgoodbeamqualityforTWBapplicationLasersforMaterialProcessing-Fiberlasers•Remotewelding-highbeamqualityenableslargeFnumberweldingcapabilitiesforbodyinwhite•Hydro-formtubecutting-flexiblefiberwithgoodbeamqualityprovidesfasterspeedwithquality•Thickplatewelding-multi-kilowattoperationprovidedeeppenetrationwelds•Precisionthinwelding-highspeedgalvooperationproduces“patternwelding”results•Sheetcutting-reliableflatsheetcuttingwithlowmaintenanceLasersforMaterialProcessing-Fiberlasers

IPG公司生产的2000瓦多模光纤激光器，在阿富汗成功执行了扫雷任务，其在恶劣的环境下（高温、震动、灰尘）稳定的表现得到美国军方一致的赞扬。"宙斯"激光扫雷系统从1986年开始使用了CO2、灯泵浦YAG、半导体泵浦YAG系统，最终选择了稳定、可靠性高、能耗极低的IPG光纤激光器。

在25-300米范围内平均30秒可以引爆一颗地雷。除了扫雷之外，还广泛用于清除雷管、手榴弹、火箭筒、等三十多种武器。如果知道地雷的准确位置，使用宙斯系统，可以在夜晚执行任务，也可以引爆埋在地表之下的装置。LaserCuttingLaserBeamQualityThebeamqualityofalaserdeterminesthefinalfocusedspotsizeofthelaserbeam.Thefinalfocusedspotsizedeterminestheenergydensityofthefocusedspot.Theenergydensitycombinedwiththepropertechniquedetermineswhattypeofmaterialprocessingisgoingtobeaccomplished.Thepowerofthelaser,beamqualityanddesignofthebeamdeliverysystemdeterminesmuchfortheprocess.AgoodqualityCO2laserbeamcanbefocusedtoaspotsizeontheorderof100micronsor0.004inches.Thisspotsizecoupledwith1kilowattoflaserpowercaneasilycutthinmaterialsincarbonsteelwhenusingoxygenassistgas.LaserCuttingLaserCuttingLasoxCuttingLasoxcuttingisaprocessfirstdevelopedbyBOCandisbeingdevelopedbyAlabamaLaserforcommercializationuseintheshipindustryandotherplatecuttingapplications.Lasoxhasdemonstratedcuttingmaterialtoseveralinchesinthickness.LaserCuttingFiberLaserCuttingTrialsThephotosbelowshowtheresultsofcuttingtrialswitha1.7kilowattIPGPhotonicsfiberlaser.Thelaserisdeliveredthrougha100micronfiber.Picture6showsthebeamdeliveryset-uponaroboticmotionsystem.TheheadusedisanALSUFOstyleheadwithacollimatorfocallengthof160mmandafocuslensof125mm.Picture7:

Fiberlasercutin1.1mmcarbonsteelhigh-pressurenitrogencut210mm/secat1.7kWLaserCuttingLaserCuttingLaserCuttingLaserCuttingLaserCutting光纤激光应用于心血管支架的精密切割光纤激光应用于心血管支架的精密切割光纤激光应用于大型设备传动机构的焊接LaserMicromachining-MedicalapplicationsFiberlasercuttingLaserWelding-FiberlaserweldingLaserWelding-PrecisionweldingThefollowingaresomemajorapplicationswherekilowattfiberlasersarereplacingbyCO2andYAGlasers:

Tailoredblankwelding

Remoteweldingofautomotivebodyinwhite

Transmissionwelding

Sintering

Heattreating

Pipewelding

Highspeedseamwelding

Hybridwelding

Sparkplugwelding

Weldingofshipstructuresbuilding

TitaniumweldinginaircraftLaserWeldingLaserWeldingHybridprocessingcombineseitherCO2orNd:YAGlaserbeamweldingwithvariousarcprocesses,includingplasmaarc,gastungstenarc,andgasmetalarcweldingLaserWelding-HybridweldingLaserWeldingLaserSurfaceTreatment-CladdingLaserSurfaceTreatmentLaserSurfaceTreatment-CladdingLaserSurfaceTreatment-CladdingLaserSurfaceTreatmentLaserSurfaceTreatment-Generating光纤激光应用于金属三维快速熔结成型系统使用IPG100W,CW,SM光纤激光器，精度为50umSLM技术制造的零件SLM制件横截面组织CrosssectionofSLMproductSLM制件表面形貌SurfaceAppearanceofSLMproductLaserSinthering–200WSingleModeLaserSurfaceTreatmentLaserSurfaceTreatment-Engraving柔性印刷陶瓷网纹辊的激光雕刻

LaserSurfaceTreatment-Engraving柔性印刷陶瓷网纹辊的激光雕刻

LaserSurfaceTreatment-Engraving激光毛化LaserSurfaceTreatment-MarkingLaserSurfaceTreatment-MarkingLaserSurfaceTreatment-peelingLaser-processesinmicrotechnology

StructuringLaserdrilling(Ceramics,metals,polymers) Nd:YAG-Lasers,Excimer-LasersLasermicroablation(Microtooling,microrapidprototyping) Excimer-Lasers,freq.conv.Nd:YAG-LasersLasersurfacemodification Excimer-LasersPackagingLasersoldering(PCBs,Connectors) cw-DiodelasersLaserwelding(Micromechanicalparts,polymerparts) Nd:YAG-Lasers,Fiber-Lasers,diodelasersLaserbonding(Silicon-Glass-Compounds) cw-Nd:YAG-LasersLaserMicromachiningLaserSelectiveSolderingSystemLaserSolderSystemisaÒTurnKeySolutionsÓforsolderingextremelydifficultsoldersitessuchasverysmallcomponents,assembliesrequiringhighlylocalizedheating,brazingandweldingapplications.LaserMicromachining-selectivesolderingLaserMicromachining-selectivesolderingLaserSolderBallJetSystem-SB2-JetTheSB2-Jetsolderballsystemistheidealsolutionforflexiblesolderballplacementandreflow.Ataspeedof10ballspersecond,itisoneofthefastestmachinesonthemarkettoday.ItprovidesareproduciblesolderbumpingtechnologyforthepackagingLaserMicromachining-SB2SolderballTSAFPCsolderbumpSolderballLasertomeltsolderball(SolderBallsize:ø0.3mm)SolderballdropontotoTSApad,filltheTSAkey-holeandjointwithFpcsolderbump;N2preventoxygenatingduringthewholesolderjetprocess.LaserMicromachining-SB2Visual:TSAkey-holeshouldbefilledwithsolder;2placesofTSAkey-holeshouldbecoveredwithsoldercompletely;Notraceburnareallowed.Peelstrength:Thepeelstrengthshouldbemorethan30gaccordingtothemanualsoldering.LaserMicromachining-SB2SB²-ApplicationsLaserMicromachining-SB2LaserweldingofleadframesLaserbeamweldingofpassiveheatsinksonstampedleadframesNd:YAG-LaserP=3kWWeldingtimet=5msWeldinggeometry<200µmLaserMicromachining-HybridmicropartsPolymerweldingofsensitiveelektronicsandmicropartsApplications:SensorsVentilsLockingsystemsMicrofluidiccomponentsMedicalproductsManufacturingdevice:DiodelaserP=5-50Wserialprocessing

v>1m/minSimultaneousprocessingt<1sLaserMicromachining-JoiningofPolymerParts

DiodePumped,repetitivelyq-switchedUV:YAGLaserOperatingmode:TEM00(gaussianpowerdistributionacrossthebeam)

Wavelength:355nm(UV)

Peakpower@3kHz:above15kwPulsewidth@3kHz:30ns(typical)Pulsestability@3kHz:7%ProgrammablePulseRate:0–20kHzLaserbeampositioning:cross-axiswithgalvanometerLaserbeamresolution:<0.00004"(1mm)Beampositionaccuracy:±0.0008"(±20mm)Fieldsize:21"by25"Max.speed:20,000viasperminuteProducingbothblindviasandthroughviasDrillingonCopperandallPCBdielectricmaterialEliminatingtheneedforpre-etchingESIModel5200LaserDrillingSystemLaserMicromachining-PCB

IMPACT2500LASERGENERATORTEA-CO2LaserWavelength:9300nmAverageOutputpower:65W(max)Pulseenergy:130mJ/cm2(max)Poweratprocessingpoint(f3.6mmmasksize):>1.64Wat50Hzpulsefrequency

Pulseenergydensity:100mJ/cm2

Pulsefrequency:500Hz(max)Beamsize:9±1x8±1mm(30mmfarfromfrontoptics)Laserbeampositioning:cross-axiswithgalvanosystemX-YTablePositionaccuracy:±5mm(±2mmrepeated)GalvanosystemScanarea:5mmx40mmPositionaccuracy:±20mm

AutoMaskchangerNumbersofpatterns:13(f0.75-f3.60)Auto-alignment(imageprocessing)CCDcamera:2unitsFieldofvision:3.2x2.4mmSearchaccuracy:±10m