学科分类
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8 个结果
  • 简介:Wetheoreticallyandexperimentallystudyself-acceleratingandself-breathingBessel-likebeamsthatfollowarbitrarytrajectories,includinghyperbolic,hyperbolicsecant,andthree-dimensional(3D)spiralingtrajectories.ThebeamshaveanoverallBessel-likeprofileintransversedimensions;however,theintensityoftheircentralmainlobebreatheswhiletravelingalongacurvedtrajectory.Suchbeamscanbereadilygeneratedexperimentallythroughappropriatephasemodulationoftheopticalwavefront.Thebeamscontributetothedesignofnewfamiliesofself-acceleratingbeams.

  • 标签: 横梁 塞尔 呼吸 螺旋轨迹 横向尺寸 相位调制
  • 简介:Theself-assembledInAs/GaAsquantumdots(QDs)withextremelylowdensityof8×10~6cm~(-1)areachievedusinghighergrowthtemperatureandlowerInAscoveragebylow-pressuremetal-organicchemicalvapourdeposition(MOVCD).Asaresultofmicro-photoluminescence(micro-PL),forextremelylowdensityof8×10~6cm~(-1)InAsQDsinthemicro-PLmeasurementsat10K,onlyoneemissionpeakhasbeenachieved.ItisbelievedthattheInAsQDshaveagoodpotentialtorealizesinglephotonsources.

  • 标签: 量子学 密度 光子源 测量技术
  • 简介:Apiece-wisetransitiondetectionalgorithmthatperformsdisplacementmeasurementsforself-mixingsensorsisdeveloped.Thealgorithmcancorrectlydetectself-mixingfringesatalowsignal-to-noiseratiointhepresenceofdisturbanceswithoutfiltering.Displacementreconstructionsbythephaseunwrappingmethodbasedonthisalgorithmareexperimentallyvalidated,withlasersubjecttothemoderatefeedbackregime.

  • 标签: 位移传感器 测算法 混合 分段 相位展开方法 信号噪声比
  • 简介:Higher-bandself-trappingandoscillation(rotation)ofnonlinearquadruplebeamsintwo-dimensional(2D)squarephotoniclatticesarenumericallydemonstrated.Underappropriateconditionsofnonlinearity,aquadruple-likebeamcanself-trapintolocalizedmodesthatresideinthesecondBraggreflectiongapthroughsingle-siteexcitation.Bychangingtheinitialorientationoftheincidentquadruplebeamrelatedtothelattices,periodicoscillationsofthelocalizedquadruplemodemaybeobtained.Thelocalizedquadruplestatebecomesarotatingdoublychargedopticalvortex(DCV)duringrotationandshouldundergocharge-flippingwhentherotatingdirectionisreversed.

  • 标签: 周期振荡 子晶格 自陷 二维 带隙 旋转方向
  • 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: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:Anoveldesignofatwo-channelopticaladd–dropmultiplexerbasedonaself-rolled-upmicrotube(SRM)ispresented.ThisdesignconsistsofanSRMthathasaparaboliclobe-likepatternalongthetube'saxialdirection,aswellasstraightsiliconwaveguidesanda180°waveguidebend.TheverticalconfigurationoftheSRMandwaveguidesisanalyzedbythecoupledmodetheoryforachievingtheoptimumgap.Inthecriticalcouplingregime,whenthedeviceservesasanopticaldemultiplexer,theminimuminsertionlossis1.94dB,andthemaximumchannelcrosstalkis-6.036dB.Also,asanopticalmultiplexer,themaximumcrosstalkbecomes-11.9dB.

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  • 简介:Wereportontheamplificationofhigh-average-powerandhigh-efficiencypicosecondpulsesinaself-madeverylarge-mode-areaYb-dopedphotoniccrystalfiber(PCF).ThePCFwithacorediameterof105μmandacorenumericalapertureof0.05ispreparedbythesol-gelmethodcombinedwiththepowdersinteringtechnique.Thefiberamplificationsystemproducesthehighestaveragepowerof255Wata10MHzrepetitionratewitha21pspulsedurationcorrespondingtoapeakpowerof1.2MW.Thisresultexemplifiesthehigh-average-powerandhigh-peak-powerpotentialofthisspecificallydesignedfiber.

  • 标签: 光子晶体光纤 皮秒脉冲 镱掺杂 MOPA 面积 极大模