简介：Thehigh-powerlaserbeaminthefinalopticsassemblyofhigh-powerlaserfacilitiesisoftenmodulatedbycontaminationparticles,whichmaycauselocalhighlightintensity,therebyincreasingthefilamentarydamageprobabilityforopticalcomponents.Tostudythegeneraldesignbasisforafinalopticsassemblytodecreasetheriskoffilamentarydamage,different-sizedcontaminationparticlesdepositedonacomponentsurfacearesimulatedtomodulatea351-nmlaserbeambasedontheopticaltransmissiontheory,andthecorrespondingsimulationresultsareanalyzedstatisticallyintermsofthepropagationcharacteristicandthelightfieldintensitydistributionofthemodulatedlaserbeam.Thestatisticalresultsshowthatcomponentthicknessanddistancebetweencomponentscantosomeextentbeoptimizedtoreducetheappearanceoflocalhighlightintensity,andthegeneraldesignbasisofcomponentthicknessandarrangementaregivenfordifferentcontrollevelsofparticlesizes.Moreover,thestatisticalresultscanalsopredictthelaserbeamqualityapproximatelyundertheexistingopticsdesignandenvironmentalcleanliness.Theoptimizeddesignforfinalopticsassemblybasedonenvironmentalcleanlinesslevelisusefultoprolongthelifetimeofopticsandenhancetheoutputpowerofhigh-powerlaserfacilities.

简介：Amethodtoevaluatedamageinopticalelementswiththenearfieldofanamplifiedspontaneousemission(ASE)beamhasbeendeveloped.Localpeakintensitiesaregenerallydistributedrandomlyinthenearfieldofalaserbeam.ThepartialcoherenceoftheASEsourceresultsinaverysmoothbeamprofile.ThecoherencetimeofASEismuchlessthanthepulsewidth.Small-scaleintensitymodulationscanbesmoothedoutrapidlywithinthetimeofapulsewidth.Intheexperiments,ASEisgeneratedfromamultifunctionalhigh-performanceNd:glasssystem,withapulsedurationof3ns,aspectralwidth(fullwidthathalfmaximum,FWHM)of1nmandanadjustableenergyrangefrom1to10J.ThedamagethresholdsofsamplesinducedbyASEaretwotothreetimeshigherthanthoseinducedbyalaserwiththesamesizeoftestspot.Furthermore,theASEbeamhasgreatpotentialforthedetectionofdefectsoveralargeareaandtheconditioningofopticalelements.

简介：Anapproachbasedoncontinuumdamagemechanicstofatiguelifepredictionforstructuresisproposed.Anewfatiguedamageevolutionequationisdeveloped,inwhichtheparametersareobtainedinasimplewaywithreferencetotheexperimentalresultsoffatiguetestsonstandardspecimens.WiththeutilizationofAPDLlanguageontheANSYSplatform,afiniteelementimplementationispresentedtoperformcouplingoperationondamageevolutionofmaterialandstressredistribution.ThefatiguelivesofsomenotchedspecimensandaPitch-change-linkarepredictedbyusingtheaboveapproach.Thecalculatedresultsarevalidatedwithexperimentaldata.

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简介：TheShenguang-IIUpgrade（SG-IIUp）facilityisanunder-constructionhigh-powerlaserdriverwitheightbeams,24kJenergy,3nspulsedurationandultravioletlaseroutput,intheShanghaiInstituteofOpticsandFineMechanics,China.Theprototypedesignandexperimentalresearchoftheprototypefinalopticsassembly（FOA）,whichisoneofthemostimportantpartsoftheSG-IIUpfacility,havebeencompletedontheninthbeamoftheSG-IIfacility.Thirty-threeshotswerefiredusing1-ωenergyfrom1000to4500Jand3-ωenergyfrom500to2403Jwitha3nssquarepulse.Duringtheexperiments,emphasiswasgiventotheprocessofopticaldamageandtotheeffectsofclean-gascontrol.AnumericalmodeloftheFOAgeneratedbytheIntegratedComputerEngineeringandManufacturingcodeforComputationalFluidDynamics（ICEMCFD）demonstratedthatafluxwithin1–5ls-1anda180speriodiseffectualtoavoidcontaminantsputteringtotheoptics.Thepresenceofsurface‘mooning’damageandsurfacespotslocatedoutsidetheclearapertureareinducedbycontaminantssuchaswire,silicagelandmillimeterorderfiberandmetal.