简介：Steadystateandtime-resolvedautofluorescencespectroscopiesareemployedtostudytheautofluorescencecharacteristicsofhumancolonictissuesinvitro.Theexcitationwavelengthvariesfrom260to540nm,andthecorrespondingfluorescenceemissionspectraareacquiredfrom280to800nm.Significantdifferenceinfluorescenceintensityofexcitation-emissionmatrices(EEMs)isobservedbetweennormalandtumorcolonictissues.Comparedwithnormalcolonictissue,lownicotinamideadeninedinucleotide(phosphate)(NAD(P)H)andflavinadeninedinucleotide(FAD),andhighaminoacidsandprotoporphyrinIX(PpIX)fluorescencescharacterizehigh-grademalignanttissue.Moreover,theautofluorescencelifetimesofnormalandcarcinomatouscolonictissuesat635nmunder397-nmexcitationareabout4.32±0.12and18.45±0.05ns,respectively.ThehighaccumulationofendogenousPpIXincoloniccancersisdemonstratedinbothsteadystateandtime-resolvedautofluorescencespectroscopies.更多还原

简介：Inthequantumkeydistributionsystem,quantumchannelisalwaysaffectedbyspontaneousRamanscatteringnoisewhenittransmitswithclassicalchannelsthatactassynchronizationanddatachannelsonasharedfiber.Tostudytheeffectofthenoiseexactly,thetemporaldistributioncharacteristicsoftheRamanscatteringnoiseareanalyzedtheoreticallyandmeasuredbyasingle-photondetector.Onthebasisofthis,aschemetodecreasethenoiseisproposed.

简介：Adoublycladdingsingle-modefiberhumiditysensorisfabricatedbyagarose.Thesensorhasaninsertionlossof0.08dBandapowerchangeof17.83dB.Theresponsesofthesensortoarelativehumidity(RH)rangeform30%to100%atatemperaturerangeform25to34Carevalidated.TheexperimentsdemonstratethattheabsorbabilityofagarosegeltomoisturedecreaseswithincreasingRHinmeasuredgas.Weproposeacalibrationmethodthatuseslookuptablesandconstructacorrespondingcalibrationmatrix.Usingthesensor,weconductreal-timemonitoringofRHinfreshconcreteduringitshardeningprocess.

简介：Thenonlineareffectsthatlimittheperformanceofthemulti-frequencyprobe(MFP)basedcoherentopticaltimedomainreflectometry(C-OTDR)areinvestigated.Basedontheoreticalanalysisandexperimentalresults,comparedwithconventionalC-OTDR,whentheprobepulsehaspowergradientwithinthepulsewidth,self-phasemodulation(SPM)andcross-phasemodulation(XPM)arestrengthenedinthenewC-OTDRscheme.Thegenerationoffour-wavemixing(FWM)isdependentonSPMandXPM,andwithmodulationfrequencyofphasemodulatorhigherthan40MHz,thestimulatedBrillouinscattering(SBS)thresholdcanbeenhancedbymorethan5dB,whichbenefitsthemaximumdynamicrangeoftheMFPC-OTDR.

简介：Real-timemeasurementofthefastaxisangleofaquarter-waveplatebasedonsimultaneousphaseshiftingtechniqueispresented.Thesimultaneousphaseshiftingfunctionisrealizedbyanorthogonalgrating,adiaphragm,ananalyzerarray,anda4-quadrantdetector.Theintensitiesofthelightbeamsfromthefouranalyzerswithdifferentazimuthsaremeasuredsimultaneously.Thefastaxisangleofthequarter-waveplateisobtainedthroughthefourlightintensityvalues.Inthismethod,rotatingelementsarenotrequired,soreal-timemeasurementisachieved.

简介：Atwo-dimensional(2D)opticaltrue-timedelay(TTD)beam-formingsystemusingacompactfibergratingprism(FGP)foraplanarphasedarrayantenna(PAA)isproposed.Theopticalbeam-formingsystemmainlyconsistsofaTTDunitbasedonthesamecompactFGP,onetunablelaserforelevationbeamsteering,andacontrolledwavelengthconverterforazimuthbeamsteering.AplanarPAAusingsuch2DopticalTTDunithasadvantagessuchascompactness,lowbandwidthrequirementfortunablelasersources,andpotentialforlarge-scalesystemimplementations.Theproof-of-conceptexperimentresultsdemonstratethefeasibilityoftheproposedscheme.

简介：Acombinationoflight-emittingdiode(LED)identificationandatime-divisionmultiplexingschemeisproposedinthisLetterforindoorlocation-basedservice.Withthescheme,thearrangementofwhiteLEDlampsandthestructureofadataframearedesignedtorealizehigh-accuracyindoorpositioningandlocation-basedpayloaddatatransmissionsimultaneously.Theresultsoftheexperimentdemonstratethattheindoorpositioningaccuracyis10cmand2Mb/sdatatransmissionwithhighsignalqualityisrealized.

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简介：Real-timevideostreamingusingultra-wideband(UWB)technologyisexperimentallydemonstratedalonglong-reachpassiveopticalnetworks(LR-PONs)withdifferentwiredandwirelessreaches.ExperimentaltestsusingexternalanddirectmodulationwithUWBwirelessradiationinthe10-and60-GHzbandsareperformed.Anultra-bendablefiberisalsoconsideredforalast-miledistribution.ThevideoqualityattheoutputoftheopticalfiberinfrastructureoftheLR-PONisassessedusingtheerrorvectormagnitude(EVM),andthelinkqualityindicator(LQI)isusedasafigureofmeritafterwirelessradiation.AnEVMbelow–17dBisachievedforbothexternallyanddirectlymodulatedLR-PONscomprisingupto125kmofopticalfiber.EVMimprovementisobservedforlongerLR-PONswhendirectlymodulatedlasers(DMLs)areusedbecauseoftheamplitudegainprovidedbythecombinedeffectofdispersionandDML’schirp.Comparedwithopticalback-to-backoperation,theLQIleveldegradestothemaximumaround20%forLR-PONsrangingbetween75and125kmoffiberreachandwithawirelesscoverageof2minthe10-GHzUWBband.ThesamelevelofLQIdegradationisobservedusingthe60-GHzUWBbandwithaLR-PONintegrating101kmofaccessnetwork,alast-miledistributionusingultra-bendablefiber,anda5.2-mwirelesslink.