简介:SpecimensofPbTesinglefilmaredepositedonGesubstratesbyvacuumthermalevaporation.Duringthetemperaturerangeof80–300K,thetransmittanceofaPbTefilmwithin2–15μmismeasuredevery20KbythePerkinElmerFouriertransforminfraredspectroscopycryogenictestingsystem.Then,therelationshipbetweentherefractiveindexandwavelengthwithin7–12μmatdifferenttemperaturesisreceivedbythefullspectruminversionmethodfitting.ItcanbeseenthattherelationshipconformstotheCauchyformula,whichcanbefitted.Then,therelationshipbetweentherefractiveindexofthePbTefilmandthetemperature/wavelengthcanbeexpressedasn(λ,T)=5.82840-0.00304T+4.61458×10~(-6)T~2+8.00280∕λ~2+0.21544∕λ~4,whichisobtainedbythefittingmethodbasedontheCauchyformula.Finally,thedesignedvalueobtainedbytheformulaandthemeasuredspectrumarecomparedtoverifytheaccuracyoftheformula.
简介:Atemperaturesensorbasedonpolarizationnon-reciprocity(PNR)infiber-opticSagnacinterferometer(FSI)wasproposed.Theexperimentalstudywasmadeprimarilyandtheresultsagreewiththeorywell.Discussionshowsthatthiskindoftemperaturesensorcanachievehighprecisionandhavegreatapplicationpotential.
简介:Alightpurplishredsapphireisheattreatedinanairtightcrucible.Thesamplechangeslittleincolorafterreceivingheattreatmentat1100°C,butturnstolightblueandblueafterbeingtreatedat1200°Cand1300°C,respectively.Beforeheating,theUV-VISabsorptionspectraofthesamplearedominatedbythe551nmbroadabsorptionbandcontributedbythed-electrontransition~4A_2→~4T_2ofCr~(3+).Afterheating,theUV-VISabsorptionspectraaredominatedbythe563nmbroadabsorptionbandcontributedbytheintervalencechargetransferofFe~(2+)-Ti~(4+).ThexrayphotoelectronspectroscopytestrevealsthattheFe~(2+)andTi~(4+)ioncontentsincreasewithincreasingtemperature.ThesapphirechangingfromlightpurplishredtoblueintheheatingprocessisowingtothefactthattheFe~(2+)andTi~(4+)contentsgrowandtheintervalencechargetransferofFe~(2+)-Ti~(4+)selectivelyabsorbsUV-VISlight.
简介:Asimplifiedringcavityforachievingaunidirectionalroomtemperaturemulti-wavelengtherbium-dopedfiberringlaserwithoutopticalisolatorisdemonstrated.ThefiberringcavityisbuiltinsuchawaythattheopticalfieldspropagatingintwodirectionssufferdifferentlossescausedbyonesampledfiberBragggrating.Furthermore,simultaneousmulti-wavelengthlasingwith0.8-nmintervalsisdemonstratedwithsinusoidalphasemodulationjustbeforethesampledfiberBragggratingtopreventsingle-wavelengthlasingandunstablewavelengthoscillation.
简介:Anewwavelengthbeamcombiningtechniqueforahigh-powerlaserdiodebarbyusingatemperaturegradientheatsinkhasbeenproposed.Thethermalcontrollingprincipleofthetemperatureheatsinkhasbeendiscussed.Ithasbeenprovedbyexperimentthatthelineartemperaturedistribution,whichgenerateslinearwavelengthspreadoftheoutputbeamsfromaLDbar,canbeobtainedbyintroducingatemperaturegradientheatsinkandtheoutputbeamscanbefocusedintoarelativesmallspotbyusingtheCzerny-Turnerbeamshapingsystem.
简介:AnovelfiberBragggrating(FBG)withtwotransmissiondipsin1310-and1550-nmregionsisproposedandinscribedbyaninfraredfemtosecondlaser.Formedbymulti-photonionization,thistypeofgratingcanwithstandtemperatureashighas800℃whichmakesitsuitableforharshenvironmentsensing.Inaddition,thetemperatureandstrainaffectthesetwodipsindifferentways,whichenablessimultaneousstrainandtemperaturesensing.Thefabrication,spectrumcharacterization,andtemperatureperformanceofthisgratingareintroduced.
简介:Influenceoftemperatureonmeasurementofsurfaceplasmonresonance(SPR)sensorwasinvestigated.SampleswithvariousconcentrationsofNaClweretestedatdifferenttemperatures.Itwasshownthatiftheaffectionoftemperaturecouldbeneglected,measurementprecisionofsaltsolutionwas0.028wt.-%.Butmeasurementerrorofsalinityca,usedbytemperaturewas0.53wt.-%inaveragewhenthetemperaturedriftwas1℃.Toreducetheerror,adouble-cellSPRsensorwithsaltsolutionanddistilledwaterflowingrespectivelyandatthesametemperaturewasimplemented.更多还原
简介:ThesensitivityofDopplerwindlidarisanimportantparameterwhichaffectstheperformanceofDopplerwindlidar.Aerosolscatteringratio,atmospherictemperature,andwindspeedobviouslyaffectthemea-surementofDopplerwindlidarwithiodinefilter.Wediscussabouttherelationshipbetweenthemea-surementsensitivityandtheaboveatmosphericparameters.Thenumericalrelationshipbetweenthemisgiventhroughthetheoreticalsimulationandcalculation.
简介:A1.3-μmwavelengthvertical-mesaridgewaveguidemulitple-quantum-well(MQW)distributedfeedback(DFB)laserwithhighdirectlymodulatedbandwidthandwideoperationtemperaturerangeisreported.Withtheoptimizationofthestrained-layerMQWsintheactiveregion,thesurroundinggraded-indexseparated-confinement-heterostructurewaveguidelayers,togetherwiththeoptimizationofthedetuningandcouplingcoefficientoftheDFBgrating,highdirectlymodulationbandwidthof16GHzatroomtemperatureandwideworkingtemperaturerangefrom-40to85℃areobtained.Themeantimetofailure(MTTF)isestimatedtobeover2×10~6h.Thedeviceissuitableaslightsourceofhigh-bit-rateopticaltransmitterswithsmallsizeandreducedcost.
简介:AFourieranalysisappliedtotheMach–Zehnderinterferometer(MZI)transmissionspectrumforsimultaneousrefractiveindex(RI)andtemperaturemeasurementsisproposedandexperimentallydemonstratedinthisLetter.InthefastFouriertransform(FFT)spectrumoftheMZItransmissionspectrum,severalfrequencycomponentsaregenerallyobserved,whichmeansthatthetransmissionspectrumoftheMZIisformedbythesuperpositionofsomedual-modeinterference(DMI)spectra,andeachfrequencycomponentrepresentsdifferentcore-claddinginterferences.WecanselectsomedominantfrequencycomponentsintheFFTspectrumoftheMZItransmissionspectrumtotaketheinverseFFT(IFFT).Then,thecorrespondingDMIpatternscanbeobtained.DuetotheshiftofthewavelengthoftheseDMIspectrawithchangesintheenvironmentalparameters,wecanusethecoefficientmatrixoftheseDMIspectraformulti-parametersensing.InthisLetter,twoDMIpatternsareseparatedfromtheresultanttransmissionspectrumoftheMZI.AstheRIandtemperaturechange,theshiftsofthetwoDMIpatternswithrespecttotheRIandtemperaturewillbeobserved.ThesensitivitiesoftheRIandtemperatureare-137.1806nm∕RIU(RIunit)and0.0860nm∕°C,and-22.9955nm∕RIUand0.0610nm∕°CforthetwoDMIs.Accordingly,itcanbeusedtosimultaneouslymeasureRIandtemperaturechanges.Theapproachcaneliminatetheinfluenceofmultipleinterferencesandimprovetheaccuracyofthesensor.
简介:Biasofring-laser-gyroscope(RLG)changeswithtemperatureinanonlinearway.ThisisanimportantrestrainingfactorforimprovingtheaccuracyofRLG.Consideringthelimitationsofleast-squaresregressionandneuralnetwork,weproposeanewmethodoftemperaturecompensationofRLGbiasbuildingfunctionregressionmodelusingleast-squaressupportvectormachine(LS-SVM).StaticanddynamictemperatureexperimentsofRLGbiasarecarriedouttovalidatetheeffectivenessoftheproposedmethod.Moreover,thetraditionalleast-squaresregressionmethodiscomparedwiththeLS-SVM-basedmethod.TheresultsshowthemaximumerrorofRLGbiasdropsbyalmosttwoordersofmagnitudeafterstatictemperaturecompensation,whilebiasstabilityofRLGimprovesbyoneorderofmagnitudeafterdynamictemperaturecompensation.Thus,theproposedmethodreducestheinfluenceoftemperaturevariationonthebiasoftheRLGeffectivelyandimprovestheaccuracyofthegyroscopeconsiderably.
简介:AseriesofAlx-(Alq3)1-xgranularfilmsispreparedonSiwaferwithnativeoxidelayerusingco-evaporationtechnique.Largelateralphotovoltaiceffect(LPE)isobserved,withanoptimalLPVsensitivityof75mV/mminx=0.35sample.ThedependenceofLPEontemperatureandAlcompositionisinvestigated,andthepossiblemechanismisdiscussed.
简介:TransientthermalimpedanceofGaN-basedhigh-powerwhitelightemittingdiodes(LEDs)iscreatedusingathermaltransienttester.Anelectro-thermalsimulationshowsthatLEDjunctiontemperature(JT)risestoaverylowdegreeunderlowdutycyclepulsedcurrent.AtthesameJT,emissionpeaksareequivalentatpulsedandcontinuouscurrents.Moreover,thediferenceinpeakwavelengthwhenaLEDisdrivenbypulsedandcontinuouscurrentsinitiallydecreasesthenincreaseswithincreasingpulsewidth.Thus,selectinganappropriatepulsewidthdecreaseserrorsinJTmeasurement.
简介:Measurementsoftheexcitationpower-dependenceandtemperature-dependencephotoluminescence(PL)areperformedtoinvestigatetheemissionmechanismsofInGaN/GaNquantumwells(QWs)inlaserdiodestructures.ThePLspectralpeakisblueshiftedwithincreasingtemperatureoveracertaintemperaturerange.ItisfoundthattheblueshiftrangewaslargerwhenthePLexcitationpowerissmaller.ThisparticularbehaviorindicatesthatcarriersarethermallyactivatedfromlocalizedstatesandpartiallyscreenthepiezoelectricfieldpresentintheQWs.Thesmallblueshiftrangecorrespondstoaweakquantum-confinedStarkeffect(QCSE)andarelativelyhighinternalquantumefficiency(IQE)oftheQWs.