摘要
建立了毫秒长脉冲激光辐射透明光学元件的多杂质加热模型,对涂有SiO_2/Al_2O_3增透薄膜的K9玻璃光学元件在毫秒激光辐照下的温度场和热应力场进行了数值模拟,分析了温度场和应力场分布的发展历程。结果表明在毫秒激光作用下,多个微小杂质团簇作为吸收热源能够导致毁灭性的损伤,且损伤同时出现在元件的前后表面,前表面为温度与应力效应共同作用,后表面为应力效应主导。数值模拟结果与实验损伤形貌观察结果吻合较好。
A multiple inclusion model of transparent optical components irradiated by millisecond long pulse laser was established.The temperature and stress field distribution and process of a K9 based component coated with SiO_2/Al_2O_3 anti-reflection films irradiated by millisecond laser were numerical calculated and analyzed.The results show that multiple micro-inclusions can serve as heating source which induce devastating damages under the action of a millisecond laser.The damage happens both from front and back surfaces.The front surface damage is caused by heat and stress while the back surface damage is dominant by stress.The damage morphologies indicated by numerical results meet well with the experimental morphologies observed.
引文
[1]B C Stuart,M D Feit,S Herman,et al.Nanosecond-tofemtosecond laser-induced breakdown in dielectrics[J].Phys.Rev.B53,1996:1749-1761.
[2]J Y Natoli,L Gallais,H Akhouayri,et al.Laser-induced damage of materials in bulk,thin-film,and liquid forms[J].Appl.Opt.2002,41:3156-3166.
[3]S C Jones,P Braunlich,R T Casper,et al.Recent progress on laser-induced modifications and intrinsic bulk damage of wide-gap optical materials[J].Opt.Eng.1989,28:1039-1068.
[4]R T Casper,S C Jones,P Braunlich.F-center accumulation as a mechanism of multiple-pulse,laser-induced bulk damage in KBr and KI at 532nm[J].Nucl.Inst.Meth.phy.Res.B.,1990,46:231-234.
[5]N Bloembergen.Laser-induced electric breakdown in solids[J].IEEE J.Quant.Electron.,1974,10:375-386.
[6]R W Hopper,D R Uhlmann.Mechanism of inclusion damage in laser glass[J].J.Appl.Phys.,1970,41:4023-4037.
[7]S Papernov,A W Schmid.Heat transfer from localized absorbing defects to the host coating material in Hf O2/Si O2multilayer systems[J].Proc.SPIE,1997,2966:283-291.
[8]S I Kudryashov,S D Allen,S Papernov,et al.Nanoscale laser-induced spallation in Si O2films containing gold nanoparticles[J].Appl.Phys.B,2006,82:523-527.
[9]Y G Shan,H B He,C Y Wei,et al.Geometrical characteristics and damage morphology of nodules grown from artificial seeds in multilayer coating[J].Appl.Opt.,2010,49:4290-4295.
[10]B Wang,Y Qin,X W Ni,et al.Effect of defects on longpulse laser-induced damage of two kinds of optical thin films[J].Appl.Opt.,2010,49:5537-5544.
[11]H B He,H Y Hu,Z P Tang,et al.Laser-induced damage morphology of high-reflective optical coatings[J].Appl.Surf.Sci.,2005,241:442-448.
[12]B Wang,H C Zhang,Y Qin,et al.Temperature field analysis of single layer Ti O2film components induced by long-pulse and short-pulse lasers[J].Appl.Opt.,2011,50:3435-3441.
[13]N Bloembergen.Role of cracks,pores,and absorbing inclusions on laser induced damage threshold at surfaces of transparent dielectrics[J].Appl.Opt.,1973,12:661-664.
[14]A E Chmel.Fatigue laser-induced damage in transparent materials[J].Mater.Sci.Eng.,1997,C49:175-190.
[15]S G Demos,M Staggs.Characterization of laser induced damage sites in optical components[J].Opt.Express.,2002,10:1444-1450.
[16]M D Feit,A M Rubenchik,D R Faux,et al.Modeling of laser damage initiated by surface contamination[J].Proc.SPIE,1996,2966:417-424.
[17]G H Liu,M Zhou,G H Hu,et al.Calculation of temperature fields with a film-substrate interfacial layer model to discuss the layer-pair number effects on the damage thresholds of La F3/Mg F2high reflectors at 355nm[J].Appl.Surf.Sci.,2010,256:4206-4210.
[18]G Dai,Y B Chen,J Lu,et al.Analysis of laser induced thermal mechanical relationship of Hf O2/Si O2high reflective optical thin film at 1064nm[J].Chin.Opt.Lett.,2009,7:601-604.