激光技術(shù)及應(yīng)用

1、激光的基礎(chǔ)、應(yīng)用及其發(fā)展Light Amplification through Stimulated Emission of Radiation引言基本原子、分子受激發(fā)射放大而產(chǎn)生的一種相干光輻射；極高的亮度，極好的方向性、單色性和相干性。 激光：Laser：激光的發(fā)明：1958激光名詞出現(xiàn) 1960 第一臺激光器出現(xiàn)激光應(yīng)用：光學(xué)：激光物理，非線性光學(xué)、激光光譜學(xué)等新興學(xué)科工業(yè)：已廣泛地利用激光進行切割、焊接、打孔、熱處理等醫(yī)學(xué)：外科手術(shù)刀，醫(yī)治很多疑難病癥 信息：計算機、音視頻顯示設(shè)備等 能源：激光核聚變 環(huán)保：環(huán)境及污染監(jiān)測 軍事：制導(dǎo)、測距、致盲和做未來高技術(shù)戰(zhàn)爭中的新武器 Arthu

2、r L. Schawlow Charles H. Townes Aleksandr M. Prokhorov Nicolay G. Basov Nicolaas BloembergenKai M. Siegbahn1964年諾貝爾物理獎1981年諾貝爾物理獎激光是一種電磁波激光是一種電磁波Light is an electromagnetic wave.Different wavelengths in the visible spectrum are seen by the eye as different colors.l lWavelengthRed: l l = 700 nm Blue:

3、 l l = 400 nm Laser-P 受激輻射受激輻射Incident PhotonExcited AtomLaser-P Stimulated Photon same wavelength same direction in phaseIncident Photon激光器的構(gòu)成激光器的構(gòu)成工作物質(zhì)工作物質(zhì)ACTIVE MEDIUMSolid (Crystal)GasSemiconductor (Diode)Liquid (Dye)激勵系統(tǒng)激勵系統(tǒng)EXCITATION MECHANISMOptical ElectricalChemical光學(xué)諧振腔光學(xué)諧振腔OPTICAL RESONAT

4、ORHR Mirror andOutput CouplerThe Active Medium contains atoms which can emit light by stimulated emission.The Excitation Mechanism is a source of energy to excite the atoms to the proper energy state.The Optical Resonator reflects the laser beam through the active medium for amplification.High Refle

5、ctanceMirror (HR)Output CouplerMirror (OC)ActiveMediumOutput BeamExcitation MechanismOptical ResonatorLaser-P HELIUM-NEON GAS LASERLaser-P Courtesy of Metrologic, Inc.固體激光固體激光SOLID STATE LASERLaser-P High Reflectance Mirror (HR)Output Coupler Mirror (OC)Elliptical ReflectorPower SupplySolid State Ro

6、dArc or Flash LampSingle LampDouble LampRear MirrorAdjustment KnobsSafety Shutter Polarizer Assembly (optional)CoolantBeamTubeAdjustmentKnobOutputMirrorBeamBeam TubeHarmonicGenerator (optional)Laser CavityPumpCavityFlashlampsNd:YAGLaser RodQ-switch(optional)Courtesy of Los Alamos National Laboratory

7、Nd:YAG LASER Q-開關(guān)開關(guān)Stored EnergyOutput PowerTimeWith Q-SwitchWithout Q-SwitchLasing beginswithout Q-switchQ-Switch opensQ-switched Pulse:1 J in 10 ns - 100 MW Normal Long Pulse:1.0 J in 1.0 ms - 1 KW TimeHROCAMQLaser-P 半導(dǎo)體激光半導(dǎo)體激光DIODE LASERLaser-P SiO2Metallic Contact10 - 20 m mmCleaved FacetCurrent

8、Distribution+-Elliptical BeamP-N Junction激光光譜激光光譜LASER SPECTRUM10-13 10-12 10-11 10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 1 10 102 LASERS200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 10600 UltravioletVisibleNear InfraredFar InfraredGamma Rays X-Rays Ultra- Visible Infrared

9、Micro- Radar TV Radio violet waves waves waves wavesWavelength (m)Wavelength (nm)Nd:YAG 1064GaAs 905HeNe 633 Ar488/515 CO2 10600XeCl 308KrF2482w wNd:YAG 532Retinal Hazard RegionArF193Communication Diode 1550Ruby 694Laser-P Alexandrite 755激光的特點：高亮度、高方向性、高單色性、高的相干性High irradiance ，Beam divergence， Mon

10、ochromaticity， Coherence1.1 激光的特性方向性：普通光源的發(fā)光無方向性，而激光的發(fā)光可以限制在幾個毫弧度立體角甚至更窄小的角度范圍，這就使得在照射方向上的照度提高了410(32) 107倍。高亮度：激光之所以有強的破壞能力是由于其本征亮度(在光照射方向)，這是激光與物質(zhì)相互作用有非凡效果的決定因素。 一般太陽光亮度大約是：103W(cm2sr)，而大功率激光器的輸出亮度可達10101017W(cm2sr)，即是說可以高出7-14個量級。單色性：由激光輻射的能量，通常集中在十分窄的光譜波段或頻率范圍內(nèi)，一般實驗室使用的光譜單色燈，單色性106，而激光可高達1010101

11、3，因此利用現(xiàn)今已有的波長可調(diào)的激光裝置可以做成波長分辨率極高的單色儀，可用來測量在不同條件下產(chǎn)生原子和分子光譜的譜線寬度。高相干性：激光不僅具有高方向性和高單色性的特點，由激光所產(chǎn)生的波列還有高度的整齊的間隔和長度，這導(dǎo)致激光通過光學(xué)干涉儀的裝置，可以使波列前后，盡管有大的光程差，仍能相干涉。 激光的應(yīng)用需要的條件 激光器必須滿足各種應(yīng)用的不同技術(shù)要求，必須高度穩(wěn)定可靠，價廉物美； 有各種配套支撐技術(shù)，比如探測器、光學(xué)系統(tǒng)、精密機械、信號處理電路和電源等。 1、已發(fā)展成規(guī)模宏大的產(chǎn)業(yè)，如光纖通信和光存儲；2、已成為先進的生產(chǎn)工具，如激光加工； 3、直接造福于人類健康，如激光醫(yī)療； 4、成為新

12、型的武器裝備，如激光制導(dǎo)炸彈 ；5、探索和研究中的激光應(yīng)用 激光材料加工技術(shù)分類Category of Laser Material Processing Technology 激光切割 Laser Cutting 激光焊接 Laser Welding 激光表面處理 Laser Surface Treatment 激光微加工 Laser Micromaching 激光快速成型 Laser Assisted Rapid Prototyping 材料加工激光器Lasers for Material Processing Carbon Dioxide Lasers-CO2 Nd:YAG Lasers

13、 Diode Lasers Fiber Lasers Excimer LasersThree primary lasing mechanisms for CO2 laser devices currently exist:1) conventional (sealed and slow flow); 2) flowing (axial and transverse);3) diffusion (no flow with the cooling walls in close proximity). Lasers for Material Processing-CO2 lasers快速軸流CO2激

14、光器 快速軸流CO2激光器是由工作氣體沿放電管軸向流動來實現(xiàn)冷卻的，且氣流方向同電場方向和激光方向一致，其氣流速度一般大于100m/s，有的甚至可達亞音速。其結(jié)構(gòu)主要由細(xì)放電管、諧振腔、高壓直流放電系統(tǒng)、高速風(fēng)機、熱交換器及氣流管道等部分組成。 特點：光束質(zhì)量好（基?；騎EM01模） 功率密度高 電光效率高，最高可達26%； 結(jié)構(gòu)緊湊 可以連續(xù)和雙制運行 Typical 6 kW Industrial CO2 LaserLasers for Material Processing-CO2 lasers橫向流動型CO2激光器 該激光器的工作氣體沿著與光軸垂直的方向快速流過放電區(qū)以維持腔內(nèi)有較低的

15、氣體溫度，從而保證有高功率輸出。單位有效諧振腔長度的輸出激光功率達10KW/m，商用器件的最大功率可達25 KW/m。但其缺點是光束質(zhì)量較差，在好的情況下可以得到低階模輸出，否則為多模輸出。這種類型的激光器廣泛應(yīng)用于材料的表面改性加工領(lǐng)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 橫流CO2激光器（以色列）6000W 橫流CO2激光器（德國）YAG激光器是以釔鋁石榴石晶體為基質(zhì)的一種固體激光器。釔鋁石榴石的化學(xué)式是Y3A15O12,簡稱為YAG。在YAG基質(zhì)中摻入激活離子Nd3(約1%)就成為Nd:YAG 。YAG激光器基本組成部分是激光工作物質(zhì)、泵浦源和諧

16、振腔 YAG激光器按輸出波形可分為連續(xù)波YAG激光器、重頻YAG激光器和脈沖激光器；按工作波長可分為106m YAG激光器、倍頻YAG激光器、和可調(diào)諧YAG激光器等 ；按泵浦方式可分為：燈泵浦和半導(dǎo)體激光泵浦YAG激光Nd:YAG Laser2kW Lamp Pumped Nd:YAG laserLasers for Material Processing-YAG lasersLasers for Material Processing-YAG lasersTypical 4 kW Industrial Nd:YAG LaserLasers for Material Processing-YA

17、G lasersDiode lasersHigh Power Direct Diode Lasers HPDDL,Lasers for Material Processing-Diode lasersLasers for Material Processing-Diode lasers1、Crystal 2、laser beam 3、output mirror 4、diode bar 5、collimation6、rear mirror 7、cooling 8、supplyDiode pumped YAG Laser (Side pumped) Diode Pumped YAG Laser(E

18、nd pumped laser)Lasers for Material Processing-Diode pumped YAG lasersThin disc pumpedLasers for Material Processing-Diode pumped YAG lasersDiagram of single module for disc laserLasers for Material Processing-Diode pumped YAG lasersFiber LasersThe fiber laser is not a Nd:YAG laser that is fiber del

19、ivered, but rather a diode-pumped, Ytterbium-based fiber laser resonator that is fiber delivered. On the whole the beam quality and power are better than the current Nd:YAG laser technology that is fiber delivered.No laser that has advanced as fast as the fiber laser. Within a few years fiber lasers

20、 have increased from watts to kilowatts! The telecom technology provided a sound technology for rapid scaling to industrial power levels. The industrial community has benefited from the telecom slow down. The new direction of the telecom technology has provided a new and exciting laser that is benef

21、iting laser material processing. Lasers for Material Processing-Fiber lasersDiagram of fiber laser; (Courtesy IPG Photonics)Lasers for Material Processing-Fiber lasers4千瓦千瓦光纖激光光纖激光60 x 80 x 160cm 尺寸尺寸400 kg 重量重量300M 長長 (=300m mm) 光纖傳輸光纖傳輸光纖激光的靈活性光纖激光的靈活性三百米以上激光頭激光頭Lasers for Material Processing-Fibe

22、r lasersLasers for Material Processing-Fiber lasersLasers for Material Processing-Fiber lasersYb鐿Er鉺Tm銩Potential and Reality of Industrial Applications for Fiber LasersFiber lasers offer a large spectrum of capabilities enabling it to be used in many different applications. Some of theindustrial app

23、lications with promising processing capabilities include: Laser marking - “Q” switched fiber lasers are being produced with up to 200 watts of average power Medical devices - Single mode power produces precision small kerf cutting High speed welding - high multi-kilowatt power levels with good beam

24、quality for TWB applicationLasers for Material Processing-Fiber lasers Remote welding - high beam quality enables large F number welding capabilities for body in white Hydro-form tube cutting - flexible fiber with good beam quality provides faster speed with quality Thick plate welding - multi-kilow

25、att operation provide deep penetration welds Precision thin welding - high speed galvo operation produces “pattern welding” results Sheet cutting - reliable flat sheet cutting with low maintenanceLasers for Material Processing-Fiber lasers IPG公司生產(chǎn)的2000瓦多模光纖激光器，在阿富汗成功執(zhí)行了掃雷任務(wù)，其在惡劣的環(huán)境下（高溫、震動、灰塵）穩(wěn)定的表現(xiàn)得到

26、美國軍方一致的贊揚。宙斯激光掃雷系統(tǒng)從1986年開始使用了CO2、燈泵浦YAG、半導(dǎo)體泵浦YAG系統(tǒng)，最終選擇了穩(wěn)定、可靠性高、能耗極低的IPG光纖激光器。在25-300米范圍內(nèi)平均30秒可以引爆一顆地雷。除了掃雷之外，還廣泛用于清除雷管、手榴彈、火箭筒、等三十多種武器。如果知道地雷的準(zhǔn)確位置，使用宙斯系統(tǒng)，可以在夜晚執(zhí)行任務(wù)，也可以引爆埋在地表之下的裝置。Laser CuttingLaser Beam QualityThe beam quality of a laser determines the final focused spot size of the laser beam. The

27、 final focused spot size determines the energy density of the focused spot. The energy density combined with the proper technique determines what type of material processing is going to be accomplished. The power of the laser, beam quality and design of the beam delivery system determines much for t

28、he process.A good quality CO2 laser beam can be focused to a spot size on the order of 100 microns or 0.004 inches. This spot size coupled with 1 kilowatt of laser power can easily cut thin materials in carbon steel when using oxygen assist gas.Laser CuttingLaser CuttingLasox CuttingLasox cutting is

29、 a process first developed by BOC and is being developed by Alabama Laser for commercialization use in the ship industry and other plate cutting applications. Lasox has demonstrated cutting material to several inches in thickness.Laser CuttingFiber Laser Cutting TrialsThe photos below show the resul

30、ts of cutting trials with a 1.7 kilowatt IPG Photonics fiber laser. The laser is delivered through a 100 micron fiber. Picture 6 shows the beam delivery set-up on a robotic motion system. The head used is an ALS UFO style head with a collimator focal length of 160 mm and a focus lens of 125 mm.Pictu

31、re 7: Fiber laser cut in 1.1 mm carbon steel high-pressure nitrogen cut 210 mm/sec at 1.7 kWLaser CuttingLaser CuttingLaser CuttingLaser CuttingLaser Cutting光纖激光應(yīng)用于心血管支架的精密切割光纖激光應(yīng)用于心血管支架的精密切割 光纖激光應(yīng)用于心血管支架的精密切割光纖激光應(yīng)用于心血管支架的精密切割 光纖激光應(yīng)用于大型設(shè)備傳動機構(gòu)的焊接光纖激光應(yīng)用于大型設(shè)備傳動機構(gòu)的焊接 Laser Micromachining-Medical applica

32、tionsFiber laser cuttingLaser Welding-Fiber laser weldingLaser Welding-Precision weldingThe following are some major applications where kilowatt fiber lasers are replacing by CO2 and YAG lasers: Tailored blank welding Remote welding of automotive body in white Transmission welding Sintering Heat tre

33、ating Pipe welding High speed seam welding Hybrid welding Spark plug welding Welding of ship structures building Titanium welding in aircraftLaser WeldingLaser WeldingHybrid processing combines either CO2 or Nd:YAG laser beam welding with various arc processes, including plasma arc, gas tungsten arc

34、, and gas metal arc weldingLaser Welding-Hybrid weldingLaser WeldingLaser Surface Treatment-CladdingLaser Surface TreatmentLaser Surface Treatment-CladdingLaser Surface Treatment-CladdingLaser Surface TreatmentLaser Surface Treatment-Generating光纖激光應(yīng)用于金屬三維快速熔結(jié)成型系統(tǒng)光纖激光應(yīng)用于金屬三維快速熔結(jié)成型系統(tǒng)使用IPG100W, CW, SM光

35、纖激光器，精度為50umSLM 技術(shù)制造的零件技術(shù)制造的零件SLM制件橫截面組織Cross section of SLM productSLM制件表面形貌Surface Appearance of SLM product Laser Sinthering 200W Single ModeLaser Surface TreatmentLaser Surface Treatment-Engraving柔性印刷陶瓷網(wǎng)紋輥的激光雕刻 Laser Surface Treatment-Engraving柔性印刷陶瓷網(wǎng)紋輥的激光雕刻 Laser Surface Treatment-Engraving激光毛化

36、Laser Surface Treatment-MarkingLaser Surface Treatment-MarkingLaser Surface Treatment-peelingLaser-processes in micro technology StructuringStructuringLaser drilling (Ceramics, metals, polymers)Laser drilling (Ceramics, metals, polymers)Nd:YAG-Lasers, Excimer-LasersLaser micro ablation (Micro toolin

37、g, micro rapid prototyping)Laser micro ablation (Micro tooling, micro rapid prototyping)Excimer-Lasers, freq. conv. Nd:YAG-Lasers Laser surface modificationLaser surface modificationExcimer-Lasers PackagingPackagingLaser soldering (PCBs, Connectors )Laser soldering (PCBs, Connectors )cw- Diode laser

38、s Laser welding (Micro mechanical parts, polymer parts )Laser welding (Micro mechanical parts, polymer parts )Nd:YAG-Lasers, Fiber-Lasers, diode lasersLaser bonding (Silicon-Glass-Compounds)Laser bonding (Silicon-Glass-Compounds)cw-Nd:YAG-Lasers Laser MicromachiningLaser Selective Soldering SystemLa

39、ser Solder System is a Turn Key Solutions for soldering extremely difficult solder sites such as very small components, assemblies requiring highly localized heating, brazing and welding applications.Laser Micromachining-selective solderingLaser Micromachining-selective solderingLaser Solder Ball Je

40、t System-SB2-JetThe SB2-Jet solder ball system is the ideal solution for flexible solder ball placement and reflow. At a speed of 10 balls per second, it is one of the fastest machines on the market today. It provides a reproducible solder bumping technology for the packagingLaser Micromachining-SB2

41、Solder ballTSAFPC solder bumpSolder ball Laser to melt solder ball (Solder Ball size: 0.3mm) Solder ball drop onto to TSA pad, fill the TSA key-hole and joint with Fpc solder bump; N2 prevent oxygenating during the whole solder jet process.Laser Micromachining-SB2 Visual: TSA key-hole should be fill

42、ed with solder; 2 places of TSA key-hole should be covered with solder completely; No trace burn are allowed. Peel strength: The peel strength should be more than 30g according to the manual soldering.Laser Micromachining-SB2SB-ApplicationsLaser Micromachining-SB2 Laser welding of lead frames Laser

43、welding of lead framesLaser beam welding of passiveheat sinks on stamped lead framesNd:YAG-Laser P = 3 kW Welding time t = 5 msWelding geometry 1 m/minSimultaneous processing t 1 sLaser Micromachining- Joining of Polymer PartsJoining of Polymer Parts Diode Pumped, repetitively q-switched UV:YAG Lase

44、r Operating mode : TEM00 (gaussian power distribution across the beam) Wavelength: 355nm(UV) Peak power 3 kHz: above 15 kw Pulse width 3 kHz : 30 ns (typical) Pulse stability 3kHz : 7% Programmable Pulse Rate : 0 20 kHz Laser beam positioning: cross-axis with galvanometer Laser beam resolution : 1.6

45、4 W at 50Hz pulse frequency Pulse energy density: 100mJ/cm2 Pulse frequency : 500 Hz (max) Beam size : 91 x 81 mm (30mm far from front optics) Laser beam positioning: cross-axis with galvano system X-Y Table Position accuracy: 5 mm ( 2 mm repeated) Galvano system Scan area : 5mm x 40mm Position accuracy : 20 mm Auto Mask changer Numbers of patterns : 13 (f0.75-f3.60) Auto-alignment (image processing) CCD camera : 2 units Field of visi