简介：Coherentdiffractionimaging(CDI)andptychographytechniquesbypassthedifficultyofhavinghigh-qualityopticsinX-raymicroscopybyusinganumericalreconstructionoftheimagethatisobtainedbyinvertingthediffractedintensityrecordedbyacharge-coupleddevicearray.However,thereconstructionoftheimagefromtheintensitydataobtainedfromaweaklydiffractingspecimenisknowntobedifficultbecauseoftheobviousreductioninsignal-to-noiseratio(SNR).Inthiscase,thespecimenonlyslightlymodifiestheprobediffractionpattern,resultingindifficultyintheidentificationofthedetailedstructureofthespecimenfromthereconstructedimagebecauseofthepoorcontrastandsharpnessoftheimage.Toaddressthissituation,amodificationintheimageretrievalalgorithmsusedintheiterativereconstructionoftheimageissuggested.Thismodificationshoulddoublethepresenceofhighspatialfrequenciesinthediffractionpatterntoenhancethecontrastandedgedetectioninexistingimagingtechniques.

简介：Acquiringdeep-spaceimageswithhighspatialresolutionandsensitivityisimportantforspace-debrissurveillanceandearlywarning.Weproposeanovelcomputationalimaging(CI)methodforhigh-sensitivityimageacquisitioninthisletter.TheproposedapproachintroducesCIintoimageformation.Theproposedcapturingprocessconductsminormodificationsforcamerastoencodemoredesirableinformationduringcapture,whichispracticalforhardwareimplementation.Thelatentimageisreconstructedbyformulatingarecoveryproblemintoanoptimizationproblem,whichissolvedwithiterativelyreweightedleastsquaretechnique.Theexperimentalresultsclearlyshowtheeffectivenessoftheproposedmethod.

简介：Weproposeaone-dimensionalintegralimaging(1DII)displaythatconsistsofadisplaypanelandagradient-apertureparallaxbarrier.Thegradient-apertureparallaxbarrierissymmetrical,anditsslitwidthsgraduallyincreasefrombothsidestothemiddle.Theleftmostandrightmostslitsareusedtofixtheviewingangle,whereastheotherslitsareusedtoincreasetheopticalefficiency.Aprototypeoftheproposed1DIIdisplayisdeveloped.Itsopticalefficiencyishigherthanthatoftheconventionaldisplay,buttheviewinganglesarethesame.

简介：Ahigh-powerpulsedpumpmethodisproposedtoobtainahigh-energyoutputwithanimprovedsignalto-noiseratio(SNR)duringpulseamplification.Basedonnumericalanalysis,theytterbium-dopedfiberamplifiersarecomparedunderdifferentpumpingconditions.Atthesamesignalgain,theoutputusingthehigh-powerpulsedpumpshowsgreatSNRimprovementandreducedoutputsignaldistortion,comparedwithacontinuous-wavepumpandalow-powerpulsedpump.Byadjustingthepumpparameters,theamplifiercanachievetheoptimaloutputSNRwithoutsacrificingthesignalgain.Webelievethatthehigh-powerpulsedpumpschemeisverysuitableforthehigh-energynanosecondpulseamplification,whichhasahighSNRrequirement.

简介：Higher-bandself-trappingandoscillation(rotation)ofnonlinearquadruplebeamsintwo-dimensional(2D)squarephotoniclatticesarenumericallydemonstrated.Underappropriateconditionsofnonlinearity,aquadruple-likebeamcanself-trapintolocalizedmodesthatresideinthesecondBraggreflectiongapthroughsingle-siteexcitation.Bychangingtheinitialorientationoftheincidentquadruplebeamrelatedtothelattices,periodicoscillationsofthelocalizedquadruplemodemaybeobtained.Thelocalizedquadruplestatebecomesarotatingdoublychargedopticalvortex(DCV)duringrotationandshouldundergocharge-flippingwhentherotatingdirectionisreversed.

简介：Weproposeahighsensitivitysensorbasedonamodenumber-encodedmulti-longitudinalmodefiberlaser.ThefiberlaserincorporatesauniformfiberBragggrating(FBG)andafiberFabry-Perotinterferometer(FFPI)assensitivecomponentsinthecavity.Thesensorcountsthenumberoflongitudinalmodes(NLM)offiberlaser,whichiscausedbythemismatchbetweenthereflectionbandofFBGandthetransmissionbandofFFPIresultingfromtheapplicationofexternalperturbationtotheFBG.AnelectricalspectrumanalyzerisadoptedtoanalyzetheNLM.Thestrainsensorisexperimentallydemonstratedtohavesensitivityofashighas0.02με/mode.

简介：TransientthermalimpedanceofGaN-basedhigh-powerwhitelightemittingdiodes(LEDs)iscreatedusingathermaltransienttester.Anelectro-thermalsimulationshowsthatLEDjunctiontemperature(JT)risestoaverylowdegreeunderlowdutycyclepulsedcurrent.AtthesameJT,emissionpeaksareequivalentatpulsedandcontinuouscurrents.Moreover,thediferenceinpeakwavelengthwhenaLEDisdrivenbypulsedandcontinuouscurrentsinitiallydecreasesthenincreaseswithincreasingpulsewidth.Thus,selectinganappropriatepulsewidthdecreaseserrorsinJTmeasurement.