简介:Anall-fiberopticallaserpulsemulti-passstretcherusingachirpedfiberBragggrating(CFBG)isdemonstrated.Pulsesfroma1053-nmmode-lockedfiberseedoscillatorarestretchedbymultiplepassingthroughachirpedfibergratingsetinafiberregenerativeamplifierstructure.Westretchthepulsefrom16psto1.855nsafterittransmitssevenloopsinthestretcher.Themainfactorsthataffectthestretchingresultsarediscussed.
简介:ASchwarzschildmicroscopewithanumericalapertureof0.2andamagnificationof130ina100μmfieldofview(FOV)isdesignedandisworkingat13.5nm.Meanwhile,aCCDisusedasadetectorwithapixelsizeof13μm×13μmandimagingareaof13mm×13mm.Theimagingqualitywithtolerancesofsystemanderrorsofmirrorsareconsidered.Weobtainthatthebeston-axesobjectresolutioncanbeuptoabout200nm,theaveragevalueis230nm,andtheresolutionisabout360nmat80μmFOV.
简介:Micro-depositionofanaluminumfilmof500-nmthicknessonaquartzsubstratewasdemonstratedbylaser-inducedforwardtransfer(LIFT)usingafemtosecondlaserpulse.Withthehelpofatomicforcemicroscopy(AFM)andscanningelectronmicroscopy(SEM),thedependenceofthemorphologyofdepositedaluminumfilmontheirradiatedlaserpulseenergywasinvestigated.Asthelaserfluencewasslightlyabovethethresholdfluence,thehigherpressureofplasmaforthethickerfilmmadethefreesurfaceofsolidphaseburstout,whichresultedinthatnotonlythesolidmaterialwassputteredbutalsothedepositedfilmintheliquidstatewasmadeirregularly.
简介:Awavelength-sweptlaserisconstructedusingafreespaceexternalcavityconfigurationcoupledwithafiberbasedringcavityatthe850nmregion.Theexternalcavityfilteremploysagalvo-mirrorscannerwithadiffractiongratingforwavelengthselection.Thefilterisconnectedtoaringcavitythroughanopticalcirculator.Theringcavitycontainsabroadbandsemiconductoropticalamplifierwithahighopticaloutput.Theperformanceofthislaserisdemonstratedwithbroadbandwidthsandnarrowlinewidths.The3dBlinewidthandthebandwidthofthissourceare0.05nm(~20GHz)and48nm,respectively.Themaximumoutputpoweris26mWat160mAcurrent.
简介:InordertoimprovetheopticalpropertiesoftheⅢ-Ⅴlaserdiodes(LDs)bymeansofH_2Splasmapassiva-tiontechnology,H_2SplasmapassivationtreatmentisperformedontheGaAs(110)surface.Theoptimumpassivationconditionsobtainedare60-Wradiofrequency(RF)powerand20-minduration.Sothelasercavitysurfacesaretreatedundertheoptimumpassivationconditions.Consequently,comparedwithun-passivatedlaserswithonlyAR/HR-coatings,thecatastrophicopticaldamage(COD)thresholdvalueofthepassivatedlasersbyH_2Splasmatreatmentisincreasedby33%,whichisalmostthesameasthatof(NH_4)_2S_xtreatment.Andthelife-testexperimenthasdemonstratedthatthispassivationmethodismorestablethan(NH_4)_2S_xsolutionwet-passivatedtreatment.
简介:The810-nmInGaAlAs/AlGaAsdoublequantumwell(QW)semiconductorlaserswithasymmetricwaveg-uidestructures,grownbymolecularbeamepitaxy,showhighquantumefficiencyandhigh-powerconver-sionefficiencyatcontinuous-wave(CW)poweroutput.Thethresholdcurrentdensityandslopeefficiencyofthedeviceare180A/cm~2and1.3W/A,respectively.Theinternallossandtheinternalquantumefficiencyare1.7cm~(-1)and93%,respectively.The70%maximumpowerconversionefficiencyisachievedwithnarrowfar-fieldpatterns.
简介:Asuccessfulbeamcleanupofa5-mJ/200-μspulsedsolid-statelasersystemoperatingat532-nmwavelengthisdemonstrated.Inthisbeamcleanupsystem,awave-frontsensor-lessadaptiveoptics(AO)systemissetupwitha20-elementbimorphmirror(BM),ahigh-voltageamplifier,acharge-coupleddevicecamera,andacontrolsoftwareimplementingthestochasticparallelgradientdescent(SPGD)algorithm.Thebrightnessofthelaserfocalspotisimprovedbecausethewave-frontdistortionshavebeencompensated.Theperformanceofthissystemispresentedandtheexperimentalresultsareanalyzed.
简介:Themulti-photonionizationspectrumofNOinthewavelengthregionof575-680nmisobtainedwithanopticalparametergeneratorandamplifier(OPG/OPA)pumpedbyapicosecondNd:YAGlaserasradiationsource.ThebandedstructureofthespectrumindicatesthatNOmoleculeisionizedinresonantmannerandthepeaksofthespectrumareassignedtothetransitionofNOmoleculefromthegroundelectronicstatetoA2∑(v'=0,1,2,3),E2∑(v'=0,1,2),F2Δ(v'=0,1,2,3)andH2∑(v'=0,1,2)intermediateresonantones.ThemoleculeconstantsaboutNO(A2∑,E2∑,F2Δ,H2∑)statesarecalculatedfromthecenterwavelengthofthespectrum.ItisalsofoundthatowingtothespecialelectronconfigurationofNO,thismoleculedoesnotfollowthenormaltransitionselectionruleofthediatomicmoleculeduringthemulti-photonprocess.