简介：ASchwarzschildmicroscopewithanumericalapertureof0.2andamagnificationof130ina100μmfieldofview(FOV)isdesignedandisworkingat13.5nm.Meanwhile,aCCDisusedasadetectorwithapixelsizeof13μm×13μmandimagingareaof13mm×13mm.Theimagingqualitywithtolerancesofsystemanderrorsofmirrorsareconsidered.Weobtainthatthebeston-axesobjectresolutioncanbeuptoabout200nm,theaveragevalueis230nm,andtheresolutionisabout360nmat80μmFOV.

简介：Theinfluenceofcircularapertureontheintensityofhigh-orderharmonicgeneration(HHG)withintensefemtosecondlaserpulsewasstudiedbothexperimentallyandtheoretically.TheintensityvarietyofHHGwiththediameterofcircularaperturewasobservedinpulsedArgas.TheresultwasdiscussedandinterpretedintermsofthetheoryofHankeltransform.ItisfoundthatusingtheGaussianbeamtruncatedbyanaperturecouldenhancetheconversionefficiencyofHHGatcertainconditions.

简介：Inthispaper,wepresentsimulationresultsofanelectroopticalvariableopticalattenuator(VOA)inte-gratedinsilicon-on-insulatorwaveguide.Thedeviceisfunctionallybasedonfreecarriersabsorptiontoachieveattenuation.Beampropagationmethod(BPM)andtwo-dimensionalsemiconductordevicesimu-lationtoolPISCES-Ⅱwereusedtoanalyzethedcandtransientcharacteristicsofthedevice.Thedevicehasaresponsetime(includingrisetimeandfalltime)lessthan200ns,muchfasterthanthethermoopticandmicro-electromechanicalsystems(MEMSs)basedVOAs.

简介：B_2O_3-P_2O_5-SiO_2(BPS)three-dimensional(3D)high-organizedpolystyrene(PS)opalsandinverseopalswithlargedomainwerefabricatedandcharacterized.Scanningelectronmicroscope(SEM)showsthreeorfoursmall'windows',indicatingthataverywellinterconnectionbetweenPSspheresofopal.Theultraviolet-visible(UV-vis)spectraindicatethatthephotonicbandgaps(PBGs)areabout710and604nmfor320-and270-nmspheresrespectively.WhileaccordingtoBragg'sequation,thesimulationresultsshouldbe762and643nm,whichmeanthat52and39nmwereshiftedtoblueregion,respectively.

简介：Manyapproachesforhigh-resolutionimagereconstructionhavebeenproposedinsomeliteratures.Oneofthemostcommonlywaysistoreconstructahigh-resolutionimagefromanumberofrotatedandtranslatedimageswithlowresolution.Inthisprocess,theexposuredifferenceamongoriginalimageswilldecreasethequalityofthereconstructedimage.Inordertoremovetheinfluenceoftheexposuredifference,alightenergymatchingmethodisproposedinthispaper.Thetheoreticalanalysisisillustratedindetails.Experimentalresultsshowthatthetheoreticalanalysisiscorrectandtheproposedmethodisvalid.

简介：Basedonthepointspreadfunctionofholographicsystem,thelateralresolutionofdigitalholographicimagingsystemwithoutanypre-magnificationisstudied.Theexpressionofresolutionlimitationofholo-graphicimagingsystemisthuspresented.Weinvestigatethepossibilitiestoimprovethelateralresolution.Thesimpleexperimentalsetupwithanoff-axisarrangementisbuilt.ByusingaU.S.AirForce(USAF)testtargetasmicroscopicobject,therecordedhologramsarereconstructeddigitallybasedontheprincipleofFresneldiffraction.Thelateralresolutionof2.76μmwithoutanypre-magnifieationisdemonstratedexperimentally,whichmatchesthetheoreticalpredictionwell.

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简介：Alow-thresholdRamaneffectinakilowattytterbium-dopednarrowbandfiberamplifiersystemisreported.TheRamanStokeslightat1120nmisachievedwiththetotaloutputpowerofonly~400W,indicatingthattheRamanthresholdofthiskilowattcodirectionalpumpedcontinuouswavefiberamplifierismuchlowerthanthepredictedvalueestimatedbytheclassicformula.Tofigureoutthemechanismofthisphenomenon,simulationsbasedonthegeneralstimulatedRamanscattering(SRS)modelareanalyzedindicatingthatthekeyfactoristhecouplingbetweenfour-wavemixing(FWM)andSRS.Thesimulationresultsareingoodagreementwithourexperiments.

简介：Weproposeanovelphotonictechniqueformicrowavefrequencymeasurementbasedontransversalmicrowavefilterswithhighresolution.Twoparallelmicrowavefilterswithsineandcosinefrequencyresponsesareobtainedbycrossgainmodulationinasinglesemiconductoropticalamplifier,whichintroducestwodifferentfrequencyresponsestoachieveanamplitudecomparisonfunction.Wealsodemonstrateaproof-of-conceptexperiment.Themeasurementerrorislessthan±0.04GHzforthefirstbandrangeof0–3.45GHzandlessthan±0.03GHzforthesecondbandrangeof3.45–5.8GHz.Ourschemeisfoundtobecapableofbeingextendedforlargerfrequencyrangemeasurementsusingashorterfiberlength.

简介：Aschemeforall-fiberclockenhancementofnon-return-to-zero(NRZ)databasedoncross-phasemodulation(XPM)effectinnonlinearfibersisproposedanddemonstratedinsimulation.Thesimulationresultsindicatethattheclock-to-dataratioofNRZsignalsat64Gb/scanbeincreasedto22.94dBbyusingthisscheme,andthepatterneffectinclockenhancedsignalsisveryweak.Theabilityofhighspeedoperationupto140Gb/softhisschemeisalsoprovedinoursimulation.

简介：High-strainInGaAs/GaAsquantumwells(QWs)aregrownbylow-pressuremetal-organicchemicalvapordeposition(LP-MOCVD).Photoluminescence(PL)atroomtemperatureisappliedforevaluationoftheopticalproperty.Theinfluenceofgrowthtemperature,V/IIIratio,andgrowthrateonPLcharacteristicareinvestigated.ItisfoundthatthegrowthtemperatureandV/IIIratiohavestrongeffectsonthepeakwavelengthandPLintensity.Thefull-widthathalf-maximum(FWHM)ofPLpeakincreaseswithhighergrowthrateofInGaAslayer.TheFWHMofthePLpeaklocatedat1039nmis20.1meV,whichgrowsat600°CwithV/IIIratioof42.7andgrowthrateof0.96mm/h.

简介：Wereportonthecontinuous-wave（CW）andpassiveQ-switchingperformanceofaminiatureYb:Y3Ga5O12crystallaserendpumpedbya935-nmdiodelaser.AmaximumCWoutputpowerof12.03Wisproducedwithanoptical-to-opticalefficiencyof54.4%,whiletheslopeefficiencyis63%.InthepassivelyQ-switchedoperationachievedwithaCr4+:YAGsaturableabsorber,anaverageoutputpowerof2.12Wat1025.2nmisgeneratedwithaslopeefficiencyof46%atapulserepetitionrateof5.0kHz.Thepulse’senergy,duration,andpeakpowerare424μJ,2.3ns,and184.3kW,respectively.

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

简介：Investigationsareperformedtoexplorehigh-repetition-ratefemtosecondlaserablationeffectsonthephysicalandchemicalpropertiesofpoly(methylmethacrylate)(PMMA).Ascanningelectronmicroscopy(SEM)isusedtocharacterizethemorphologychangeinthelaser-ablatedregions.TheinfraredandRamanspectroscopyrevealsthatthefundamentalstructureofthePMMAisalteredafterlaserablation.Wedemonstratethecumulativeheatingismuchgreaterduringhigh-repetition-ratefemtosecondlaserablation,supportingaphotothermaldepolymerizationmechanismduringtheablationprocess.

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

简介：WeestablishasystemtomeasurethefunctionalabsorptioncrosssectionofphotosystemII(PSII)(σPSII)andmaximumquantumyieldofphotochemistryinPSII(Fv/Fm).Thesystemutilizesasequenceofhighfrequencyexcitationflashesatmicrosecondintervalstoinduceamicrosecond-levelfluorescenceyieldcurve.ParametersσPSIIandFv/Fmarecalculatedbyfittingthecurveusingnonlinearregression.Experimentalresultsshowthattherelativestandarddeviation(RSD)ofthesystemislessthan3%,andthecorrelationcoefficientofFv/Fmvaluesmeasuredbythissystemandthosemeasuredbypulseamplitudemodulationmethodis0.950.

简介：Inapracticalcouplingsystem,acylindricalmicrolensisusedtocollimatetheemissionofahighpowerlaserdiode(LD)inthedimensionperpendiculartothejunctionplane.Usingpassivealignment,theLDisplacedinthefocusofthecylindricalmicrolensgenerally,regardlessoftheperformanceofthemultimodeopticalfiberandtheLD.Inthispaper,amorecompleteanalysisisarrivedatbyray-tracingtechnique,bywhichtheangleθoftherayafterrefractioniscomputedasafunctionoftheangleθooftheraybeforerefraction.ThefocusofthecylindricalmicrolensisnotalwaystheoptimalpositionoftheLD.Infact,inordertoachieveahighercouplingefficiency,theoptimaldistancefromtheLDtothecylindricalmicrolensisdependentonnotonlytheradiusRandtheindexofrefractionnofthecylindricalmicrolens,butalsothedivergenceangleoftheLDinthedimensionperpendiculartothejunctionplaneandthenumericalaperture(NA)ofthemultimodeopticalfiber.Theresultsofthisdiscussionareingoodagreementwithexperimentalresults.

简介：一个简单波长无关的规模因素模型为靠近环的干涉仪纤维被建立眼的回转仪(IFOG)和一个方法被建议为空格申请在高效IFOG把规模因素作为容忍的放射和温度马厩。一半波浪电压(在不同波长和温度的多功能旋转罗盘薄片的V)被测量，调节的人的放射无关的固有的参数被选出并且发现与温度并且稍微成正比波长依赖者。试验性的IFOG被开发，规模因素分别地在不同温度并且在Co60照耀下面被测量。不到10ppm规模因素不稳定性在40以内被完成？？

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简介：HighorderBraggscattering(M=2andM=3)operationsofthedistributedfeedbackdyedopedsol-gelsilicalasersareachievedusingthesecondharmonicoutputofaNd:YAGlaserasthepump.Laserlinewidthoflessthan0.06nmandconversionefficiencyof0.7%forM=3and11%forM=2aremeasured.Wavelengthtuningofabout15nmaroundtheemissioncenterhasbeenrealizedbyvaryingtheintersectionangle.