学科分类
/ 1
16 个结果
  • 简介:Inthispaper,anultrathinmetalenshasbeenproposedbasedonaholographicmetasurfacethatconsistsofelongatedaperturesin40nmgoldfilm,whichexhibitintriguingpropertiessuchason-andoff-axisfocusingandalsocanconcentratelightintomultiple,discretespotsforcircularlypolarizedincidentlights.First,thespatialtransmissionphasedistributionsofthedesignedmetalenswitharbitraryfocusingcanbeobtainedbycomputergeneratedholography.Then,thediscretephasedistributionscanbecontinuouslyencodedbysubwavelengthnanoapertureswithspatiallyvaryingorientationsingoldfilm.Thesimulationresultsshowthatourdesignedmetalenscanworkefficientlyfordifferenttypesoffocusing.Finally,ourmetasurfaceshowssuperiorbroadbandcharacteristicsbetween670and810nm,andthecorrespondingfocallengthsofthedesignedlensesalsocanbeefficientlymodulatedwiththeincidentlightsatdifferentwavelengths.

  • 标签:
  • 简介:Asimplifiedmathematicalmodelwascreatedformeasurementofthermalexpansioncoefficientsofthinsheetmaterialswithholographictechnique.Experimentalset-upscorrespondingtothemathematicalmodelweredesignedandbuiltforbothtestsaboveroomtemperatureandatlowtemperatures.Afringecontroltechniquewasintroducedforlowtemperaturemeasurementstocompensaterigidbodymovement,THinsheetspecimensofsiliconandaluminumalloy(7075)weretestedwiththedevelopedtechnique.Thetestedresultsareingoodagreementwithreporteddataandthusverifythevalidityofthedevelopedtechnique.TheThermalexpansioncoefficientsofthetestedmaterialsrangedfrom2.5×10^-60C^-1to23.6×10^-6oC^-1.

  • 标签: 材料 热膨胀系数 全息技术 测量
  • 简介:Wepresentadigitalholographicmicroscopewhereinthesampleisilluminatedbystructuredlighttoenablethecaptureofadditionalobjectspatialfrequencies.ReconstructedimageswithincreasedspatialresolutionareobtainedbyseparatingandsynthesizingbandwidthsofdifferentfrequencyregionsintheFourierdomain.Thetheoreticalanalysisandexperimentalresultsarepresented.

  • 标签: 结构照明 数字全息 显微镜 分辨率增强 空间频率 空间分辨率
  • 简介:Inordertofindtherelationshipsbetweenthedistortionruleoftheconcreteanditssurroundingstressfield,areal-timeopticalholographicsetupisusedtorecordthedistributionandthevariationofthesamples,thewaveformsofultrasonicemissionstimulatedbythemicro-cracksarerecordedbyatransientautomaicwaveformrecorderthdeterminethetime,locationandintensityoftheactionsofmicro-cracks,Theexperimentresultsareworthystudying.Thismethodprovidesausefulexperimentalapproachtostudythebrittlenessmaterials.

  • 标签: 时实全像技术 扭曲 干扰测量法 混凝土
  • 简介:Thetomographytechniqueiscommonlyusedforthereconstructionofholographicinterferometry.However,thecurrentreconstructionmethoddoesn'tconsiderthemeasurementerrorswhicharenon-avoidableinthemeasurementandwilldegradethereconstructionquality.Thefactorsaffectingthereconstructionqualityareanalyzedandthedistributionlawofthereconstructionerrorwithexperimentalerrorsisdiscussed.Finally,amethodtoimprovethereconstructionquality—theKalmanfiltermethodispresented.

  • 标签: 全息干涉法 温度测量 3维温度场 卡尔曼滤波器
  • 简介:Laguerre–Gaussianbeams,asaspecialmodelwithspiralphasestructure,havebeenintensivelyinvestigated.HolographicgratingmethodisaconvenientmethodofgeneratingLaguerre–Gaussianbeamsandmeasuringtheirorbitalangularmomenta.Butduetosomeinevitableadversefactorssuchaslateraldisplacement,angulardeflectionandellipticalincidentprofileofincidentbeam,thepracticaleffectivenessshouldbereevaluated.Thispaperisdevotedtothestudyontheinfluencesoftheabovementionedthreeadversefactorsontheholographicgratingmethod.Thecharacteristicsofthemodedecompositionofdiffractiveorderandtherelativepowersoftheorbitalangularmomentumeigen-statesarealsogiven.

  • 标签: 光学 Laguerre-Gaussian光束 轨角动量 全息光栅衍射
  • 简介:Anon-axisholographiczoneplateoranoff-axisholographiczoneplateusedforthesiliconsolarcellwillhaveasolarenergyconversionfactorof2.5.Andthecombinationofthetwoplateswillhaveitsconversionfacftorof5.Especiallyfortheuseofsilverhalidephotographicemulsion,thecostcanbecutdowndramatically.

  • 标签: 太阳能 光电管 太阳能电池 全息区极板
  • 简介:Itiswellknownthatopticaltomographycanaccuratelyandquantitativelyre-constructtherefractiveindexfieldofatransparentmediumanddisplaythethreedimensionalimageofotherthysicalquantitiesrelevanttotemperatureordensity.Inthispaper.anewmultidirectionalholographicinterferometricsystemisbuilt,andtwokindsofimagetecon-structionalgoritmaareintroducedandanautomaticimageprocessingsystemofinterfero-gramisdesigned.Athreedimentsionalasymmetricgadflowfieldaboveacombustorisexperi-mentallyinvestigatedwithholographicinterferormetry.Thereconstructedtemperaturesaresimilartothosemeasuredwithathermocouple.

  • 标签: 光层折X射线摄影术 正交全息摄影 重建算法 温度测量 图像处理
  • 简介:我们使用对扩大holographicRicci黑暗精力(ERDE)诊断的statefinder模型没有并且与到学习的相互作用他们的行为。我们为不同盒子阴谋各种各样的参数的轨道。非交往的模型不到达LCDM点,这被显示出{1,0}并且因为相互作用做statefinder对的进化,交往的被赞成{r,s}相当不同。

  • 标签: 能量模型 利玛窦 诊断 全息 相互作用
  • 简介:Inholographicencryption,doublerandom-phaseencodingintheFresneldomain(DRPEiFD)isaprevalentencryptionmethodbecauseitislenslessandsecure.However,noisesbringadverseeffectsduringdecryption.Inthisletter,weintroducequick-response(QR)codingduringencryptiontoresistnoises.WetransformtheoriginalinformationintoaQRcodeandthenencryptthecodeasahologramthroughDRPEiFD.Toretrievetheinput,wedecryptthehologramintheoppositemannertotheencryptionandsubsequentlyobtainaQRcodewithnoises.Byscanningthiscodewithproperapplicationsinsmartphones,wecanobtainanoise-freeretrieval.Numericalexperimentsandimagesscannedbyasmartphoneareshowntovalidateourproposedmethod.

  • 标签: 加密方法 快速响应 全息图 抗噪音 安全 双随机相位编码
  • 简介:MeasuringtheObjectDeformationbyRealTimeHolographicInterferometrywithAutomaticalyCalculatingHologram①WANGWensheng,XUBin(Changc...

  • 标签: BSO Crystal HOLOGRAPHIC INTERFEROMETRY HOLOGRAPHY
  • 简介:Inordertoimprovetheresolutionofdigitalholographywithacommon-dimensioncharge-coupleddevice(CCD)sensor,thepointspreadfunctionsarebrieflyderivedforthecommonlyusedandpracticalpost-magnification,pre-magnification,andimage-planedigitalholographicmicroscopicsystems.Theultimateresolutionsofthesesystemsareanalyzedandcompared.Theresultsshowthattheultimatelateralresolutionofpre-magnificationdigitalholographyissuperiortothatofpost-magnificationdigitalholographyinthesameconditions.Wealsodemonstratethattheultimatelateralresolutionofimage-planedigitalholographyhasnocorrelationwiththephotosensitivedimensionoftheCCDsensor,anditisnotsignificantlyrelatedtothepixelsizeofthesensor.Moreover,boththeultimateresolutionandtheimagingqualityofimage-planedigitalholographyaresuperiortothatofpre-andpost-magnificationdigitalholographicmicroscopy.High-resolutionimaging,whoseresolutionisclosetotheultimateresolutionofthemicroscopeobjective,canbeachievedbyimage-planedigitalholographyevenwithasubmillimeter-dimensionsensor.Thissystem,bywhichperfectimagingcanbeachieved,isoptimalforcommonlyuseddigitalholographicmicroscopy.Experimentalresultsdemonstratethecorrectnessofthetheoreticalanalysis.

  • 标签: DIGITAL holography DIGITAL HOLOGRAPHIC microscopy image-plane
  • 简介:ResearchdemonstratesthataFresnelhologramcanbegeneratedandsimultaneouslyencryptednumericallybasedonasecretsymmetrickeyformedbythemaximallengthsequence(M-sequence).Themethodcanbedirectlyextendedtoencryptavideoholographicclipinaframe-by-framemanner.However,giventhelimitedcombinationofsignalsinthefamilyofM-sequence,hackingthesecretkeythroughtrialanderrorcanbetimeconsumingbutnotdifficult.Inthisletter,weproposeamethodthatisdifficulttocrackwithbruteforceforencryptingaholographicvideosequence.AnM-sequenceisfirstrandomlyassignedtoencrypteachframeoftheholographicvideosignal.Subsequently,theindexoftheselectedM-sequence,whichisnecessarytodecryptthehologram,isencryptedwiththeRSAalgorithmbeforetransmittingtothereceivingend.Atthereceivingend,thedecoderisprovidedwithaprivatekeytorecovertheindexforeachframe,andthecorrespondingM-sequenceisusedtodecrypttheencodedhologram.

  • 标签: 菲涅耳全息图 混合加密 视频序列 计算机生成 数值 对称密钥加密
  • 简介:Twodifferentmethodsfromgraphicprocessingunit(GPU)andcentralprocessingunit(CPU)areproposedtosuitablyoptimizelook-uptablealgorithmsofcomputergeneratedholography(CGH).Thenumericalsimulationsandexperimentalresultsshowthatwecanreconstructagoodqualityobject.ThecomputationofCGHforathree-dimensional(3D)dynamicholographicdisplaycanalsobespedupbyprogrammingwithourproposedmethod.Itcanoptimizebothfileloadingandtheinlinecalculationprocess.Thephase-onlyCGHwithgigabytedataforreconstructing10MBobjectsamplingsisgenerated.Inaddition,theproposedmethodeffectivelyreducedtimecostsofloadingandwritingofflinetablesonaCPU.ItisbelievedtheproposedmethodcanprovidehighspeedandhugedataCGHfor3Ddynamicholographicdisplaysinthenearfuture.

  • 标签: 全息显示 三维动态 字节 计算机 计算全息图 中央处理单元