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简介：ThispaperstudiesSyntheticApertureRadar(SAR)imagescontaminatedbythecoherentspecklenoisewiththemultiresolutionanalysisofwavelettransform.ThisstudyshowsthattheinfluencesofthespeckleondifferentfrequencycomponentsoftheSARimagearedifferent,andthattheSARimageandthespecklehavedifferentmannersofsingularity.So,thispaperpresentsadenoisingmethodofwaveletanalysistoreducethespeckle.Someexperimentsapprovethatthismethodnotonlysuppressesthespeckleeffectively,butalsopreservesasmuchtargetcharacteristicsoftheoriginalimageaspossible.ItshowsthatthisdenoisingmethodofwaveletanalysisoffersaveryattractivealternativetosuppressthecoherentspecklenoiseoftheSARimage.

简介：Weintroduceakindofnumber-conservingcoherentstateinRindlerspacewhichcandescribethequantumstateofthermalparticlesobservedinRindlerspace.ThisisbasedontheUnruheffectthatthethermalparticlesseenbyanacceleratingobserverinflatspacecanbeseenbyaninertialobserverincurvedspaceunderaconformaltransformation.

简介：Inthispaper,wecalculatetheresolutionofaphotorefractiveincoherent-to-coherentopticalconverterontheimageplaneforsmalldiffractionefficiencybytakingintoaccounttheopticalimagingcharacteristicsoftheimaginglens.Forathingrating,weobtainahighresolution,whichiscomparablewiththeexperimentalresults.

简介：Thispaperdiscussestheamplitude-squaredsqueezingforthesuperpositionoftwocoherentstateswiththeirphasedifferencesbeingseparatelyπ/2,3π/2,andπ,aswellasforthesuperpositionstateoftwopseudoclassicalstates.Accordingtotheanalysis,itisfoundthatthesuperpositionstateoftwocoherentstateswiththeirphasedifferencesπ/2and3π/2,andthesuperpositionstateoftwopseudoclassicalstatesbothdoexhibittheamplitude-squaredsqueezing.Also,somespecificstatesarefoundtoexhibitevenstrongersqueezingeffectswhenrelativephaseofthesuperpositionisequaltotheaveragephotonnumber.Amplitude-squaredsqueezingisdependentonthedifferenceinphasebetweentwocoherentstates.

简介：Theproblemofbearingestimationofcoherentsignalimpingiogonanarrayofarbitrarygeometryisstudied.Bothapproachesaredeveloped,thefirstonesynthesizestheobservedarraydataintotheoutputsofalinearuniformarrayandthenprocessesthemviaconventionaltechniquessuchasspatialsmoothingetc.Thesecondapproachisbasedontheinvariantsubspacerotationoperationwhichisequivalenttothetranslationaldisplacementoftheartay,linearlyindependentsignalvectorsareobtainedtherebytospanperfectlythesignalsubspace.Ascomparedwiththeconventionalprocessingtechniques,theapproachbasedoninvariantsubspacerotationdoesnotleadtoaneffectivedecreaseinaperturesizeandthereforeadecreaseinresolutioncapability.Thecomputersimulationsareconductedtodemonstratetheeffectivenessofthepresentedapproaches.

简介：Thevelocityprofile,turbulenceintensityprofile,streakystructureandburstingfrequencyinturbulentboundarylayersoveraflatplatewithcompliantcoatingswereinvestigatedbyLaserDopplerAnemometryandcondi-tionalsamplingtechniques.Thisexperimentledtotheconclusionsthatinboundarylayerflowsonacompliantwall,ascomparedwiththatonarigidwall,theloglawregionwasextendedfurtherawayfromthewall,andthatthemaximumvalueofeachturbulenceintensityprofileinthenearwallregionwasreducedandtheburstingfrequencyobviouslydecreasedwiththecompliantcoatings.Onepointworthyofnoticewasthattheaboveresultswereverymuchlikethoseofpolymerdragreductionexperiments.

简介：Anovelschemeemployinglow-densityparity-check(LDPC)codesinatmosphericopticalcommunicationsystemisproposed.Wedeploycoherentdetectionatthereceivingsideintheproposedscheme.Toreducebiterrorrate(BER)andenhancethesystemperformance,LDPCcodesareexploitedandcoherentreceiverisusedtoimprovethereceivingsensitivity.Experimentsareimplementedtoevaluatetheperformanceofthetransmissionsystem.Theatmosphericchannelattenuationsaresetto20-30dB/km.ThecoherentdetectionwithLDPCcodescanreducethereceivedpowerrequirementby~4dBmattheBERof10-9.

简介：Anoverviewoftheprogressonpulse-preserving,coherent,nonlinearfiber-basedsupercontinuumgenerationispresented.Thecontextencompassesvariouswavelengthrangesandpumpsources,startingwithsilicaphotoniccrystalfiberspumpedwith1.0μmfemtosecondlasersuptochalcogenidestep-indexandmicrostructuredfiberspumpedfromopticalparametricamplifierstunedtomid-infraredwavelengths.Inparticular,silicaandsilicatebasedall-normaldispersion(ANDi)photoniccrystalfibershavebeendemonstratedforpumpingwithfemtosecondlasersoperatingat1.56μmwiththerecordedspectracovering0.9–2.3μm.Thismatchesamplificationbandsofrobustfiberamplifiersandfemtosecondlasers.Thereviewthereforefocusesspecificallyonthiswavelengthrange,discussingglassandnonlinearfiberdesigns,experimentalresultsonsupercontinuumgenerationuptothefundamentallimitofoxideglassfibertransmissionaround2.8μm,andvariouslimitationsofsupercontinuumbandwidthandcoherence.Specifically,theroleofnonlinearresponseagainsttheroleofdispersionprofileshapeisanalyzedfortwodifferentsoftglassANDifiberspumpedatmorethan2.0μm.Aspatio-temporalinteractionofthefundamentalfibermodewithmodespropagatinginthephotoniclatticeofthediscussedANDifibersisshowntohavepositiveeffectsonthecoherenceofthesupercontinuumatpumppulsedurationsof400fs.Finally,thedesignanddevelopmentofgraded-index,nanostructuredcoreopticalfibersarediscussed.Insuchstructuresthearbitraryshapingofthecorerefractiveindexprofilecouldsignificantlyimprovetheengineeringflexibilityofdispersionandeffectivemodeareacharacteristics,andwouldbeaninterestingplatformtofurtherstudytheintermodalinteractionmechanismsandtheirimpactonsupercontinuumcoherenceforsubpicosecondlaserpumpedsetups.

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简介：从在应用物理femtosecond加速器设备的上海研究所的femtosecond电子捆的协调THz同步加速器放射的产生和观察被报导。我们描述实验安装并且介绍象力量和光谱那样的THz放射性质的第一结果。

简介：Inthefarfieldoftheintensitydistributionofthebeamdeliveredbyatwo-stagetransient–collisionalexcitationX-raylaser(XRL),anon-expectedinterferencepatternthatisstablefromshottoshothasbeendiscovered.Itisdemonstratedthattheinterferenceiscausedbytheemergenceofanimaginarysourceintheamplifyingplasma,whichisphasematchedtotheradiationofthegenerator.TheobservedphenomenoniscalledanX-raycoherentmirage.Toexplaintheobtainedresults,anewtheoreticalapproachisdeveloped.ThebasicessentialconditionsforformationoftheX-raymirageareformulated,andpossibleapplicationsarediscussed.Thispaperdetailstheexperiments,includingtheformulationofthenecessaryandsufficientconditionsforformationoftheX-raymirage,andpossibleapplicationsarediscussed.

简介：激光阶段噪音(LPN)在光协调系统起一个重要作用。基于Viterbi-Viterbi搬运人阶段评价(用户终端设备)的算法，在协调接收装置上强加的LPN的效果为调音的照阶段移动(QPSK)被调查，调音的8阶段移动(8PSK)和16照振幅调整(16正交调幅)光协调系统分别地。模拟结果证明在阶段评价算法的最佳的块长度是在LPN和添加剂白人Gaussian噪音(AWGN)之间的折衷，并且取决于调整格式的水平。到在协调接收装置的数字变换器(模数转换器)的类似物的决定要求独立于LPN或调整格式的水平。为103的位错误率(BER)，模数转换器的要求的位数字是6，并且获得为更高的分辨率是边缘的。

简介：Thispaperreportstheexperimentalresultsonelectromagneticallyinducedabsorption(EIA)spectraobservedinthesystemwhichdoesnotsatisfycompletelytheconditionsgivenbyLezamaetal[1999Phys.Rev.A594732].EIAsignalsonthetransitionsintheCsD2lineareabletobeobserved,whereFgFe=Fg-1asopensystems.TheoreticalmodelofLezamaetalisgoodforthecaseFgFe=Fg-1,consideringspontaneoustransferofatomiccoherencesorpopulationsthismodelisnotabletoexplainourexperimentalresultsobtainedinthecaseFgFe=Fg-1.ThispaperoffersatheoreticalmodelwhichisabletowellexplainthecaseFgFe=Fg-1.ItalsousesthistheoreticalmodeltoexplainthesplitandshiftofEIApeaks,whichhavebeenobtainedinexperiments.

简介：TheCMSIGUANAprojecthasimplementedanopenanalysisarchitecturethatenablesthecreationofanintegratedanalysisenvironment.Inthis"analysisdesktop"environmentaphysicistisabletoperformmostanalysis-relatedtasks,notjustthepresentationandvisualisationstepsusuallyassociatedwithanalysistools.ThemotivationbehindIGUANA'sapproachisthatphsicsanalysisincludesmuchmorethanjustthevisualisationanddatapresentation.Manyfactorscontributetotheincreasingimportanceofmakinganalysisandvisualisationsoftwareanintegralpartoftheexperiment'ssoftware:objectorientedandevermoreadvanceddatamodels,GRID,andautomatedhierarchicalstoragemanagementsystemstonamejustafew.Atthesametimetheanalysistoolkitsshouldbemodularandnon-invasivetobeusableindifferentcontextswithinoneexperimentandgenerallyacrossexperiments.Ideallytheanalysisenvironmentwouldappeartobeperfectlycustomisedtotheexperimentandthecontext,butwouldmostlyconsistofgenericcomponents.WedescribehowtheIGUANAprojectisaddressingtheseissuesandpresentboththearchitectureandexamplesofhowdifferentaspectsofanalysisappeartotheusersandthedevelopers.

简介：平淡的波浪重叠途径不能在一块协调的声学的地的重建和预言被使用，因为分开单个来源产生的压力是不可能的。根据协调的声学的地的重叠理论，一个新奇方法基于联合波浪重叠途径被开发重建并且由造匹配在全息图表面和来源之间的矩阵的联合压力预言协调的声学的地。方法能重建个人的表面的声学的信息采购原料，并且预言也从每来源和全部的协调的声学的地罐头散发的声学的地自发地被计算是可能的。试验性、数字的模拟结果证明这个方法能有效地解决holographic重建和协调的声学的地的预言，它能也被用作一种协调的声学的地分离技术。这个新奇方法上的学习扩大声学的雷射摄影术技术的应用程序范围。

简介：三身体、四身体的界限状态的证据与ultracold原子在一系列很最近的实验被报导了。这里，我们经由一个概括原子分子学习多碱的分子的协调创造黑暗状态的技术。实质上由使中介更整齐或tetramer说unpopulated，二隧道的干扰被显示出起一个重要作用在的建设性的量，例如在ultracold温度的协调atom-pentamer变换。

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简介：Coherentstructuresareessentialforthemomentumexchangeandturbulenceproductioninwall-boundedturbulentflows.Diversifiedcoherentstructureshavebeenobservedinturbulentboundarylayers,andhairpin-basedvorticesdominatemostoftherelevantliterature.However,thereisnoconsensusyetontheoriginandformingmechanismofhairpinvortices.Herein,fivecornerstonespertainingtotheframeworkofhairpin-basedcoherentstructuresarereviewed,andthreedifferenthairpingenerationmechanismsareclarified.Next,thetime-resolvedtomographicparticleimagevelocimetry(Tomo-PIV)isusedinanearlyturbulentboundarylayer(Reθ=420)toinvestigatetheoriginofhairpinvortices.Thetimelinesrevealatriangularbulgeinthelow-speedstreak(LSS),andtheinitialroll-upoccursattwosidesofit.Meanwhile,thematerialsurfacesmanifestasathree-dimensional(3D)wavestructureintheLSS,whichmaysupportthemodelofasoliton-likecoherentstructure(SCS).Subsequently,themethodofLagrangian-averagedvorticitydeviationisusedtodetectearlyvortices.Wefindthatthe3Dwavestructureisflankedbytwovortices,thusconfirmingtheroll-upoftimelinesanddemonstratingtheadvantageoftheLagrangiancriteriaincapturingstructuresincomplexflows.Theseresultssuggestthatvariouscoherentstructuresmayevolvefromthemetamorphosisof3Dwavestructuresandtheirlaterinteraction.Finally,thelimitationsoftraditionalexperimentalandpost-processingtoolsarediscussed.