简介:Wetheoreticallyandexperimentallystudyself-acceleratingandself-breathingBessel-likebeamsthatfollowarbitrarytrajectories,includinghyperbolic,hyperbolicsecant,andthree-dimensional(3D)spiralingtrajectories.ThebeamshaveanoverallBessel-likeprofileintransversedimensions;however,theintensityoftheircentralmainlobebreatheswhiletravelingalongacurvedtrajectory.Suchbeamscanbereadilygeneratedexperimentallythroughappropriatephasemodulationoftheopticalwavefront.Thebeamscontributetothedesignofnewfamiliesofself-acceleratingbeams.
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.
简介:Apiece-wisetransitiondetectionalgorithmthatperformsdisplacementmeasurementsforself-mixingsensorsisdeveloped.Thealgorithmcancorrectlydetectself-mixingfringesatalowsignal-to-noiseratiointhepresenceofdisturbanceswithoutfiltering.Displacementreconstructionsbythephaseunwrappingmethodbasedonthisalgorithmareexperimentallyvalidated,withlasersubjecttothemoderatefeedbackregime.
简介:Higher-bandself-trappingandoscillation(rotation)ofnonlinearquadruplebeamsintwo-dimensional(2D)squarephotoniclatticesarenumericallydemonstrated.Underappropriateconditionsofnonlinearity,aquadruple-likebeamcanself-trapintolocalizedmodesthatresideinthesecondBraggreflectiongapthroughsingle-siteexcitation.Bychangingtheinitialorientationoftheincidentquadruplebeamrelatedtothelattices,periodicoscillationsofthelocalizedquadruplemodemaybeobtained.Thelocalizedquadruplestatebecomesarotatingdoublychargedopticalvortex(DCV)duringrotationandshouldundergocharge-flippingwhentherotatingdirectionisreversed.
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℃.
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.
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.
简介:Wereportontheamplificationofhigh-average-powerandhigh-efficiencypicosecondpulsesinaself-madeverylarge-mode-areaYb-dopedphotoniccrystalfiber(PCF).ThePCFwithacorediameterof105μmandacorenumericalapertureof0.05ispreparedbythesol-gelmethodcombinedwiththepowdersinteringtechnique.Thefiberamplificationsystemproducesthehighestaveragepowerof255Wata10MHzrepetitionratewitha21pspulsedurationcorrespondingtoapeakpowerof1.2MW.Thisresultexemplifiesthehigh-average-powerandhigh-peak-powerpotentialofthisspecificallydesignedfiber.