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18 个结果
  • 简介:TheRamanspectrafromleukemiccellline(HL60)andnormalhumanperipheralbloodmononuclearceils(PBMCs)areobtainedbyconfocalmicro-Ramanspectroscopyusingnear-infraredlaser(785nm)excitation.Thescanningrangeisfrom500to2000cm-1.ThetwoaverageRamanspectraofnormalPBMCsandcarcinomacellshavecleardifferencesbecausetheirstructureandamountofnucleicacid,protein,andothermajormoleculesarechanged.Thespectraarealsocomparedandanalyzedbyprincipalcomponentanalysis(PCA)todemonstratethetwodistinctclustersofnormalandtransformedcells.Thesensitivityofthistechniqueforidentifyingtransformedcellsis100%.更多还原

  • 标签: 光谱学 黎曼光谱 白血病细胞 激光
  • 简介:Scalefactorofaconstantratebiasedringlasergyro(RLG)isstudiedboththeoreticallyandexperimentally.Byanalyzingexperimentaldata,wefindthattherearethreemaintermscontributingtothescalefactordeviation.Oneofthemisindependentoftime,thesecondvarieslinearlywithtimeandthethirdvariesexponentiallywithtime.Theoreticalanalysesshowthatthefirsttermiscausedbyexperimentalsetup,thesecondandthethirdarecausedbyun-uniformthermalexpensionandcavitylossvariationoftheRLG.

  • 标签: 气象学 大气探测 探测设备 有偏环状激光陀螺仪 比例因子
  • 简介:一个简单波长无关的规模因素模型为靠近环的干涉仪纤维被建立眼的回转仪(IFOG)和一个方法被建议为空格申请在高效IFOG把规模因素作为容忍的放射和温度马厩。一半波浪电压(在不同波长和温度的多功能旋转罗盘薄片的V)被测量,调节的人的放射无关的固有的参数被选出并且发现与温度并且稍微成正比波长依赖者。试验性的IFOG被开发,规模因素分别地在不同温度并且在Co60照耀下面被测量。不到10ppm规模因素不稳定性在40以内被完成??

  • 标签: 干涉型光纤陀螺 温度稳定 标度因数 性能 波长依赖性 辐射测量
  • 简介:Nitridatedβ-Ga_2O_3(100)substratewasinvestigatedasthesubstrateforGaNepitaxialgrowth.Theeffectsofnitridationtemperatureandsurfaceroughnessofβ-Ga_2O_3wafersontheformationofGaNwerestudied.Itwasfoundthatthemostoptimizednitridationtemperaturewas900°C,andhexagonalGaNwithpreferredorientationwasproducedonthewell-polishedwafer.Thenitridationmechanismwasalsodiscussed.

  • 标签: 单晶体 β-Ga2O3 氮化镓 光学应用
  • 简介:Hybridoctagonal-ringmicrolasersareinvestigatedforrealizingastableoutputfromasiliconwaveguidebasedonatwo-dimensionalsimulation.Theinnerradiusoftheringisoptimizedtoachievesingle-modeandlow-thresholdoperation.Usingthedivinylsiloxane-benzocyclobutene(DVS-BCB)bondingtechnique,ahybridAlGaInAs/Sioctagonal-ringmicrolaserverticallycoupledtoasiliconwaveguideisfabricatedwithasidelengthof21.6μmandaninnerradiusof15μm.Asingletransverse-modeoperationisachievedwithathresholdcurrentdensityof0.8kA∕cm~2andaside-modesuppressionratioabove30dB,andastableoutputfromthelowersiliconwaveguideisobtained.

  • 标签: 环形激光器 稳定输出 混合动力 硅波导 八角环 单模式
  • 简介:WeexaminethesaturationofrelativecurrentgainofIn0.53Ga0.47As/InPsinglephotonavalanchediodes(SPADs)operatedinGeigermode.Thepunch-throughvoltageandbreakdownvoltageoftheSPADscanbemeasuredusingasimpleandaccuratemethod.Theanalysismethodistemperature-independentandcanbeappliedtomostSPADs.

  • 标签: 雪崩二极管 击穿电压 单光子 测定 增益饱和 穿通
  • 简介:ThisLetterreportstheformationofperiodicsurfacestructuresonNi–Fefilmirradiatedbyasinglefemtosecondlaserpulse.Aconcavelenswithafocuslengthof-150mmisplacedinfrontofanobjective(100×,NA=0.9),whichtransformstheGaussianlaserfieldintoaringdistributionbytheFresneldiffraction.Periodicripplesformontheablationareaaftertheirradiationofasinglefemtosecondlaserpulse,whichdependsonthelaserpolarizationandlaserfluence.Weproposethattheringstructureofthelaserfieldleadstoasimilartransientdistributionofthepermittivityonthesamplesurface,whichfurtherlaunchesthesurfaceplasmonpolaritons.Theinteractionoftheincidentlaserwithsurfaceplasmonpolaritonsdominatestheformationofperiodicsurfacestructures.

  • 标签:
  • 简介:ACe3+tion-dopedα-NaYF4singlecrystalofhighqualityisgrownsuccessfullybyanimprovedfluxBridgmanmethodundertheconditionsoftakingthechemicalrawcompositionofNaF:KF:YF3:CeF3inthemolarratioof30∶18∶48∶4,wheretheKFisshowntobeaneffectiveassistantflux.Thexraydiffraction,absorptionspectra,excitationspectra,andemissionspectraoftheCe3+t-dopedα-NaYF4singlecrystalaremeasuredtoinvestigatethephaseandopticalpropertiesofthesinglecrystals.TheabsorptionspectrumoftheCe3+t:α-NaYF4showsastrongbandthatpeaksatthewavelengthof300nm.TheemissionspectrumoftheCe3+t:α-NaYF4emitsanintenseultraviolet(UV)bandatthewavelengthof332nmundertheexcitationof300nmlight.Twoseparatedluminousbandsof330and350nm,whichcorrespondtothetransitions5d→2F25∕2and5d→F7∕2,canbeobtainedbyGaussfitting.ThestrongemissionintensityattheUVbandandtheexcellentopticaltransmissionintherangeofUVwavelengthsindicatethatCe3+t:α-NaYF4singlecrystalscanbeconsideredasapromisingmaterialforUVlasers.

  • 标签: 单晶体 CE 离子掺杂 吸收光谱 发射光谱 紫外波段
  • 简介:Atheoreticalinvestigationiscarriedoutintothecrossphasemodulation(XPM)inanasymmetricdoubleAlGaAs/GaAsquantumwellsstructurewithacommoncontinuum.Itisfoundthat,combiningresonanttunneling-inducedtransparencyandconstructiveinterferenceinthethird-orderKerreffect,agiantXPMcanbeachievedwithvanishinglinearandnonlinearabsorptions,accompaniedbythevelocitiesoftheprobeandsignalfieldsbeingmatched.Furthermore,thisgiantXPMcouldinduceaπ-phaseshiftatasingle-photonlevelwhichisfavorablefortheapplicationsintwo-qubitquantumlogicgates.

  • 标签: 非对称双量子阱 单光子 信号 交叉相位调制 诱导 隧道
  • 简介:Consideringasingle-modelasersystemwithcross-correlatedadditivecolorednoiseandmultiplicativecolorednoise,westudytheeffectsofcorrelationamongnoisesonthenormalizedintensitycorrelationfunctionC(s).C(s)isderivedbymeansoftheprojectionoperatormethod.Theeffectsoftheself-correlationtimeτ_1oftheadditivecolorednoise,τ_2ofthemultiplicativecolorednoise,andtheeffectofthecross-correlationtimeτ_0betweenthetwonoisesonC(s)arediscussedbynumericalcalculation.Forthecaseofpositivecorrelation(λ>0),itisfoundthatwhena_0>0thenormalizedintensitycorrelationfunctionC(s)increaseswiththeincreaseofToorτ_2,andwithvalueofτ_0orτ_2becominglarger,C(s)comestosaturation.Withincreasingtheself-correlationtimeτ_1oftheadditivenoise,aminimumandamaximumwillappearoncurveofC(s)asa_0>0.Ifa_0<0,C(s)decreaseswiththeincreaseofτ_0,τ_1,andτ_2.

  • 标签: 光强度 关联功能 单一激光系统 交叉关联噪音
  • 简介:Anoptimizeddesignoflaserrangefindingsystemusingtheself-mixingeffectinasingle-modevertical-cavitysurface-emittinglaser(VCSEL)isproposed.Inordertoimprovetherangingaccuracyandexpanddynamicmeasurementrange,weapplydifferencefrequencyanalogphase-lockedloop(PLL)insteadoffastFouriertransform(FFT)toprocesssignal,andchoosetheoptimumtriangularwavefrequencyfm=500Hzandsmallmodulationcurrent△Ip-p=0.28mAtomodulatesingle-modeVCSEL.Theexperimentresultsshowthat,withoutcontrollingthelaser'stemperature,therangingaccuracyisbetterthan2mmandthemeasurementdynamicrangeisaslargeas50-500mmwhenthesamplingtimeis0,1sandtheroomtemperatureis0-55℃.

  • 标签: 最优化设计 激光测距 VCSEL 自混合效应
  • 简介:Thetransmissionpropertiesofone-dimensionalphotoniccrystalscontainingdouble-negativeandsingle-negativematerialsarestudiedtheoretically.Aspecialkindofphotonicbandgapisfoundinthisstructure.Thisgapisinvariantwithscalingandinsensitivetothicknessfluctuation.Butwhenchangingtheratioofthethicknessoftwomedia,thewidthofthegapcouldbeenlarged.Thedefectmodesareanalyzedbyinducingalineardefectlayerinthestructure.Itisfoundthatthenumberofdefectmodeswillincreasewhenthethicknessofthedefectlayerbecomeslarger.更多还原

  • 标签: 晶体 底片材料 光学性能 物理学
  • 简介:AhighlyTm-dopedleadgermanateglassfiberisdevelopedusingtherod-in-tubemethod.The~2μmlaserbeamqualityofthefiberis~1.5.Theleadgermanatecompositefiberjumpersarehomemadeforallthefiberlaserinvestigations.Whencoreispumpedbya1590nmYb/Erfiberlaser,amaximumlaseroutputof313mWisachievedata670mWpumppower,andthecorrespondingslopeefficiencyis~52.8%.Moreover,byusinga2cmlongleadgermanatefiberasthegainmedium,a33mW1942nmTmlaserisalsodemonstrated.

  • 标签: 激光光束质量 复合纤维 锗酸盐 TM 掺杂 光纤激光器
  • 简介:Aversatileandlow-costsingle-beamself-referencedphase-sensitivesurfaceplasmonresonance(SPR)sens-ingsystemwithultra-highresolutionperformanceispresented.Thesystemexhibitsaroot-mean-squarephasefluctuationof±0.0028°overaperiodof45min,i.e.aresolutionof±5.2×10~(-9)refractiveindexunits.Theenhancedperformancehasbeenachievedthroughtheincorporationofthreedesignelements:atruesingle-beamconfigurationenablingcompleteself-referencingsothatonlythephasechangeassociatedwithSPRgetsdetected,adifferentialmeasurementschemetoeliminatespurioussignalsnotrelatedtothesensorresponse,andtheeliminationofretardationdriftsbyincorporatingtemperaturestabilizationintheliquidcrystalphasemodulator.Ourdesignshouldbringthedetectionsensitivityofnon-labelingSPRbiosensingclosertothatachievablebyconventionalfluorescence-basedtechniques.

  • 标签: 等离子体 光束 灵敏度 共振传感器
  • 简介:ThestimulatedBrillouinscattering(SBS)thresholdaffectedbyrepetitionrateandpulsedurationinasinglefrequencynanosecondpulsedfiberamplifierisstudied.TheexperimentalresultsdemonstratethattheSBSthresholdcanbeimprovedeitherbyreducingtherepetitionrateorbynarrowingthepulseduration;however,theaveragepowermaybelimitedinsomecases.Otherwise,twoevaluationmethodsfortheSBSthresholdinthefiberamplifierarecomparedanddiscussed,aimingtoobtainamoreaccuratedescriptionfortheSBSthresholdinoursingle-frequencyamplifiersystem.

  • 标签: 受激布里渊散射 光纤放大器 纳秒脉冲 阈值 峰值功率 单频
  • 简介:Amethodtothree-dimensionalpositionmovingparticleswithonelensandtwocamerasisproposed.Twoparticleimageswithdifferentdegreesofdefocusingareadoptedtosolvetheambiguousproblemofparticlepositions.Asingle-lensdual-camerasystemisdevelopedtosimultaneouslycapturethesetwoimagesforthemovingparticles.Themeasurementprinciplesandtheoreticalanalysisareintroducedfirst,andthensimulatedinvestigationsandexperimentalresearcharediscussed.Themeasurementerrorsinthesimulationsandexperimentsarelessthan1%and4%,respectively,in20timesthedepthoffieldofthesystem,whichvalidatesthefeasibilityofthismethod.

  • 标签: 运动粒子 相机系统 单镜头 定位方法 散焦 三维
  • 简介:Anopticalbandpassfilter(OBF)isanimportantelementwhosepropertiesconsiderablyinfluencetheoutputperformanceofasinglesidebandmulticarriersourcebasedonare-circulatingfrequencyshifter.TheinfluenceoftheOBFintheloopontheoutputspectrumistheoreticallyanalyzed.Numericalsimulationsandexperimentsarealsocarriedout.Resultsshowthatthesteepnessanddeepnessofanonflat-topfilterinfluencethestabilityofthespectrumofanoutputmulticarrier.Toobtainmulticarrieroutputwithtonetonoiseratio(TNR)>26dBanderrorvectormagnitude(EVM)<0.25,thesteepnessratioofthefiltershouldbegreaterthan0.75anddeepnessshouldbelargerthan0.99.

  • 标签: 输出性能 带通滤波器 移频器 循环 基础 波源
  • 简介:Adiode-end-pumpedelectro-optic(EO)Q-switchedNd:YVO4laseroperatingatrepetitionrateof10kpps(pulsespersecond)wasreported.AblockofLa3Ga5SiO14(LGS)singlecrystalwasusedasaQ-switchandthedriverwasametaloxidesemiconductorfieldeffecttransistor(MOS-FET)pulserofhighrepetitionrateandhighvoltage.Atcontinuouswave(CW)operation,theslopeefficiencyofthelaserwas46%,andmaximumoptical-to-opticalefficiencywas38.5%.Usinganoutputcouplerwithtransmissionof70%,a10-kppsQ-switchedpulsetrainwith0.4-mJmonopulseenergyand8.2-nspulsewidthwasachieved,theopticalconversionefficiencywasaround15%,andthebeamqualityM2factorwaslessthan1.2.

  • 标签: Q调制Nd:YVO4激光器 La3Ga5SiO14单晶电光调制器 金属氧化物半导体 激光技术