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官方公共微信论坛大放送——Eastfdtd学生试用版 - 微波仿真论坛
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论坛大放送——Eastfdtd学生试用版
为感谢微波论坛为我们提供这样一个优秀的与大家交流的平台，也感谢大家对我们的支持，现奉上Eastfdtd学生试用版，供大家交流。该试用版有效期至日。 && &&&想试用EastFDTD吗？现在只需要简单填写一张EastFDTD试用申请表，就可以方面的获得EastFDTD试用版了，还不赶快行动。 &&EastFDTD试用申请表
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... 呵呵...感謝提供試用交流... 我搶第一個....
刚才有点小问题&&现在可以下啦
請問您擺上去的檔案是 EastFDTD_1.6_Trial_Build_0312.rar 7.X MB 嗎？&&只有一些文件...@@
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引用第12楼cem-uestc于 17:05发表的&&:&有空再评价EastFDTD操作使用情况&& 要等有空~, 老师肯定有很多话要说~~
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lz好， &&我想问您一点问题： &&关于您在几个sample中的到的图形结果， &&是利用这个eastFDTD得到的，还是导入其他软件得到的呀？
引用第17楼whopawho于 17:22发表的 : &lz好， &我想问您一点问题： &关于您在几个sample中的到的图形结果， &....... &&whopawho你好，你所指的应该是数据的后处理吧，现在我们的数据是保存在数据文件中的，你可以方便的直接导入到matlab中查看输出图形结果。我们现在和后续工作中将把数据的后处理集成进来。感谢支持，如有什么疑问可联系我们。
～～&&好的，谢谢！&&～～
后处理可否输出到tecplot或ensight？&这两个后处理还是很强大的
软件计算过程中会经常蹦出提示对话框，然后程序运行终止，这种设计是您有意如此的吗？
引用第21楼whopawho于 13:37发表的 : &软件计算过程中会经常蹦出提示对话框，然后程序运行终止，这种设计是您有意如此的吗？ &&恩，是的，呵呵。点击确定确定就可以继续计算了，计算过程不会受影响 &如果计算时间比较长觉得框麻烦，可以申请完整试用就没这个框了，同样免费
引用第22楼yj09-03-17 13:51发表的 : &恩，是的，呵呵。点击确定确定就科技继续计算了，计算过程不会受影响 &如果计算时间比较长觉得框麻烦，可以申请完整试用就没这个框了，同样免费[表情] &&&我想申请您说的完整试用可以吗？&&我现在也在测试一些程序，&&对话框老蹦出来很麻烦～
whopawho 你好，如果你想申请我们的试用版的话，请来电与我们沟通确认一下具体完整试用事宜。我们的电话是021- 不知道你是哪个学校的？
请问，east fdtd能不能实现基于mpi的并行编程计算啊？
Eastfdtd有可以进行并行计算的网络版本，还没有正式发布
那咱们并行计算的网络版本，楼主预计什么时候能发布呢？ 在国外有没有能实现并行计算的fdtd软件啊？ 谢谢楼主。
这个其实在我们的早期版本中已经有并行计算，现在版本升级后其中有一些结构做了改动，所以很快就可以加进去。国外软件中并行运算的应该还是有的吧
可以实现无限大周期结构斜入射吗？
以前实验室有人测试了一个叫GEMS得软件，据说做的很烂。&&引用第28楼yj09-03-18 12:42发表的 : &这个其实在我们的早期版本中已经有并行计算，现在版本升级后其中有一些结构做了改动，所以很快就可以加进去。国外软件中并行运算的应该还是有的吧
引用第30楼batista于 18:33发表的 : &以前实验室有人测试了一个叫GEMS得软件，据说做的很烂。 & &不知道你想表达什么意思
研究了好久发现只能垂直入射的。
source的(theta,fai)这两个参数就是传播的方位角，可以定义不同的入射角度。
引用第30楼batista于 18:33发表的 : &以前实验室有人测试了一个叫GEMS得软件，据说做的很烂。 & &&GEMS是美国宾州州立大学的余文化教授开发的，主要针对大型问题的并行FDTD计算，其实GEMS做得还是很到位，应该说很专业，要费不少功夫能掌握，初学者很头痛。掌握了你就对FDTD算法及应用，差不多要成为半个专家了，呵呵
引用第33楼ziseshan266于 14:11发表的 : &source的(theta,fai)这两个参数就是传播的方位角，可以定义不同的入射角度。 &&我也试过的，但是好像不起作用。
请问：用这个eastfdtd软件能仿真光子晶体的投射谱，感觉不是很正确啊
就是说比方例子五的时候，你那个缺陷的导模的投射率怎么会那么小呢？&&还是例子五，当我不想使用默认的光源的时候，我只能变换边界条件和计算模式才能使用自定义光源，是吗&&还有记录投射谱的时候只能使用默认光源和探测器吗，默认光源只是线光源
我如何不用默认光源，用一个高斯脉冲光源得到这个光源频率的投射率呢？？
不用默认模式，需要自定义光源并且自定义数据记录面，然后计算透射率。
终于见到国产的了，很想支持一下，无奈例子好像都是光电子方面的，没有电磁场方面的，应该给几个这方面的嘛，尤其这个软件还放在微波论坛！真是想说爱你不容易啊！
终于见到国产的了，很想支持一下，无奈例子好像都是光电子方面的，没有电磁场方面的，应该给几个这方面的嘛
我刚发现就到期了,我汗死了还怎么下啊有没有延长试用期的啊
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Powered by PW【EastFDTD】The transmitted properties of terahertz wave through metallic hole arrays07
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【EastFDTD】The transmitted properties of terahertz wave through metallic hole arrays07
April30,2011/Vol.9,Suppl；Thetransmittedproperties；metallicholearrays；DongLi(????)1,ShiweiShu(；JinGe(????)2,ShuhongHu(?；DepartmentofPhysics,Shan；NationalLaboratoryforInf；200083,Chin
April30,2011/Vol.9,Supplement/CHINESEOPTICSLETTERSThetransmittedpropertiesofterahertzwavethroughmetallicholearraysDongLi(????)1,ShiweiShu(??????)1,FangfangLi(??????)1,GuohongMa(??????)1?,JinGe(????)2,ShuhongHu(??????)2,andNingDai(????)2DepartmentofPhysics,ShanghaiUniversity,Shanghai200444,China2NationalLaboratoryforInfraredPhysics,ShanghaiInstituteofTechnicalPhysics,ChineseAcademyofScience,Shanghai200083,China?Correspondingauthor:ghma@sta?.ReceivedJanuary1,2011;acceptedJanuary1,2011;postedonlineJanuary1,2011Terahertz(THz)wavetransmissionthroughathinmetalfilmwithperiodicarraysofsubwavelengthrectangularholesisinvestigatedsystematically.Therolesofthewaveguideresonancesandsurfaceplasmonpolaritons(SPPs)inextraordinarytransmissionarealsoclarified.Thetransversewaveguideresonances(hole-shapedependence)dominatesthepositionandwidthofmaximumtransmission.Inaddition,theperiodicityoftheholearraysdominatesthepositionofminimumtransmissionduetotheexcitationofSPP,whichactsasaband-stopfilterintheTHztransmissionspectra.OurresultsclearlydemonstratethattheextraordinarytransmissioninTHzfrequencyisoriginatedfromthetransversewaveguideresonancesthatbehavewithaSPP-likecharacter.Simulationbasedonfinite-differencetime-domain(FDTD)agreeswellwiththeexperimentalresults.OCIScodes:040.0,230.7370.doi:10.3788/COL0.1Theextraordinarytransmissionofelectromagneticwavesthroughtwo-dimensional(2D)arraysofsubwavelengthholesperforatedinthinmetallicfilmshasattractedgreatinterestsincethepioneeringworkpublishedbyEbbesenetal.in1998[1].Subsequently,extensiveexperimentalandtheoreticalstudieshavebeencarriedouttoelucidatetheunderlyingphysicsbehindtheenhancedtransmissionproperties[2,3].Theexcitationofcoupledsurfaceplas-monpolaritons(SPPs)ontheupperandlowerinterfacesofthemetalgrating[2,4?6]isawidelyacceptedmech-anismfortheenhancedtransmission.However,Kleinetal.[7]demonstratedexperimentallythatextraordinarylighttransmissionwasstronglyin?uencedbytheindivid-ualshapeoftheholeunderstudy.UsingtheFabry-P′erot[8]resonancemodel,Takakuraetal.successfullyexplainedtheenhancementofthetransmissioninathickmetal-licslit.Throughrigorouscoupledwaveanalysis,Caoetal.evenconcludedthatthesurfaceplasmons(SPs)playeda“negativerole”inlighttransmissionthroughasubwavelengthslitarray[9].ThetheoreticalmodelingbyRuanetal.[10]inarandomarrayofmetallicholesdemon-stratestheimportanceoftheshaperesonanceintrans-mission,showingtheenhancedtransmissionresultsfromtwodifferentresonances:localizedwaveguideresonances(i.e.,Fabry-P′erotresonance)andSPresonances.How-ever,theexactcausebehindtheenhancedtransmissionremainscontroversial,andthereisnoglobalconsensusyet.Intheterahertz(THz)frequencies,extraordinarytransmissionphenomenahasalsocaughtgreatattentioninrecentyears[11?15].Inthisletter,thetransmissionpropertiesofthethinmetallicfilmwithperiodicarraysofrectangularsubwave-lengthholeshavebeeninvestigatedsystematicallyusingTHztime-domainspectroscopy(THz-TDS)system.Asimplebuteffectiveanalyticalmodelisproposed,whichcanexplainalmostalltheexperimentaldataincluding11/S0000000mostpreviouspublishedresultssuccessfully.Themodelrevealsthatboththeshapeandperiodicityofmetal-licholearraysaffectthetransmissionpropertiesofthemetallicgratinginTHzregime,whereintheshapesofmetallicholedominatethepositionandwidthoftrans-missionmaxima,andtheperiodicitiesdominatethepo-sitionoftransmissionminima.OurexperimentalresultsclearlydemonstratethattheextraordinarytransmissioninTHzfrequencyiscausedbytheshaperesonanceofthemetallichole,ratherthanSPPcontribution.Numer-icalsimulationbasedonfinite-differencetime-domain(FDTD)agreeswellwithexperimentalfindings,andthesimulationalresultsalsoshowgoodagreementwithex-perimentaldatareportedintheliterature.Comparedwiththeopticalregion,THzwaveisaveryspecialandinterestingpartinelectromagneticspectrum.Duetoadrasticincreaseinthevalueofdielectricfunc-tion,mostmetals(suchasAl,Ag,Au,andCu)resem-bleinmanywaysaperfectelectronicconductor(PEC),andthenegligiblepenetrationdepthoftheelectromag-neticfieldsindicatesthata?atmetallicfilmdoesnotsupportanySPP.However,thedesignedSPPs(orsayspoof-SPPs)occurinametallicfilmperforatedwithpe-riodicalholearrays[16].Thespoof-SPPsplayverysimi-larrolesastherealones.Althoughtheenergypositionofthespoof-SPPisoverlappedcompletelywiththatofRayleighanomalyintheTHzregionforaPECfilm,theircontributionstolighttransmissionaredistinguishedduetothedifferentcharacteristicsoftheRayleighanomaliesandSPPs.In1902,Wooddiscoveredthattheorderofdiffractionwillvanishwhenitemergestangenttotheplaneofthegrating.Later,Rayleighexplainedtheseanomaliesun-derthename“passing-offorders”.Therefore,thewave-lengthsofRayleighanomaliescanbeobtainedfromthec2011ChineseOpticsLetters??CHINESEOPTICSLETTERS/Vol.9,Supplement/April30,2011gratingequationfornormalincidenceasexpressedby[17]:λR=Ln,(1)wherenisthewavelengthdependentrefractiveindexofsurroundingmedium,iandjareintegers,andListhelatticeconstantofgrating.The“passing-offorders”areforthefirstandhigherorders,ratherthanforthezero-order.Therefore,asinmoststudies,ifwefocusonthezero-ordertransmissionoflight,Rayleighanomalies,asreportedbyseveralpreviousworks[18?20],indicatea“discontinuity”inatransmissionspectrum,ratherthanthetransmissionminima.Rayleighanomalydenotesthattheenergyofevanescentdiffractedorderisbeingredis-tributedamongtheremainedpropagatingorders(includ-ingzero-order),whichistheoriginofthe“discontinuity”inthezero-orderdiffraction.Ontheotherhand,thewavelengthofSPPresonanceinaperiodicalstructurefornormalincidenceischaracterizedbythedispersionrelation:λL√sp=mdε,(2)m+εdwhereλspisthevacuumwavelengthoftheexcitedSPP;εmandεdaredielectricconstantsofmetalanddielectricsurrounding,respectively.Asmentionedpreviously,inTHzfrequency,thedielec-tricconstantofmetalisseveralordershigherthanthatofdielectrics,i.e.,εasanidealmmetal.??εd,andthemetallicfilmcanbetreatedHence,Eqs.(1)and(2)canbeunifiedas:λL√sp=λR=di+j.(3)ItindicatesthatthewavelengthsofSPPexcitationareoverlappedcompletelywiththoseoftheRayleighanoma-liesintheTHzfrequencyregion.Asforanindividualmetallichole,thereexistsashape-dependencewaveguidemode.Here,weconsiderarect-angularsubwavelengthholeasacavity,thewaveguideresonancesarecomposedoftwocomponents:transverseandlongitudinalmodes.Themetalfilminvestigatedinthepresentstudyisathinmetalfilmwithathicknessofabouthundredsofnanometers.ThewavelengthsofourTHzwavesourcearehundredsofmicrometers,whicharemuchlargerthanthecut-o?wavelengthoflongitudinalmodes.Thereforethelongitudinalmodesarenotsup-portedinthethinfilm,andonlythetransversewaveg-uidemodeistakenintoaccountasthemechanismoflocalizedresonance,whichisalsocalled22]half-wavelengthresonanceintransversedirection[21,.Thesamplesinthisstudyaremetalrectangularholearraysfabricatedonfusedsilicasubstrate.Brie?y,anAllayerwithathicknessofabout220nmwasdepositedonafusedsilicasubstratebymagnetronsputteringtech-nique,withphotolithographyprocessingtoformade-signedmetalrectangularholearrays.Figure1showstheopticalimageofatypicalstructurewithaperiodof200μm.ForTHzspectroscopycharacterization,atransmis-sionTHz-TDSinthefrequencyrangeof0.1?2.0THzwasused.DetailsoftheTHz-TDSsystemaredescribedinourpreviouspapers[23,24].ThewaveformoftheTHzwaveinthetimedomainwasmeasureddirectly,andtheamplitudeandphasespectrawereobtainedbyFouriertransformfromthetime-domainwaveforms.Ablankfusedsilicawiththesamethicknesswasalsousedasareference.Therefractiveindexoffusedsilicachangedlittleovertheinvestigatedfrequency,anditwastreatedasaconstantofabout1.95inthisstudy.Thisisveryclosetothevaluereportedinapreviouswork[25].TheFDTDsimulationwasbasedonEASTFDTDsoft-ware.Inoursimulations,theincidentwavewithfre-quencyrangedfrom0to2.0THz,propagatedalongthez-directionandilluminated(atnormalincidence)onametalfilmdrilledwithperiodicholearraysonfusedsilicasubstrate.TheTHzwavespropagatedwithpolar-izationperpendiculartothelongedgeoftherectangularholes.Periodicboundaryconditionswereappliedtotheboththex-andy-directions,andaperfectlymatchedlayer(PML)boundaryconditionwasappliedinthez-direction.Duetothefactthatthethicknessofthesubstratewasmuchlargerthanthatofthemetalfilm,andthicknessofsilicasubstrateconsideredasasemi-infinite.Inaddition,becauseofaverylargenegativedielectricconstant6intheTHzfrequency(ontheorderof105～10)formostmetals,theconductivityoftheALfilmisusuallytakenasperfectconductorduringFDTDsimulation.Forthetransmissionandre?ectionspectracalculation,weonlycollectedthedatafromthezero-orderdiffraction.First,westudytheroleoftheholeperiodicityinthebehaviorofthezero-ordertransmissionoftherectangu-larholearrays.InordertoinvestigatetheroleofWood’sanomaly,threesamplesweredesignedandhadaholeshapeof150×50(μm)andwithvariedperiodicitiesof180,200and220μm,respectively.Inthemeasurement,theTHzwaveswithpolarizationperpendiculartothelongedgeoftherectangularholes(E⊥x)impingeonthesampleatnormalincidence(Fig.1).TheTHzwavetransmissionthroughthearrayswasnormalizedtothesubstrateofthearray,10]inordertoob-tainthetransmissionoftheholes[1,7.Figure2showsthetransmissionspectraofthesamplesatnormalinci-dence.Itisclearlyseenthatthepositionsoftransmissionminimaarelocalizedat0.7,0.77,and0.85THzforthestructureswithperiodicitiesof220,200and180μm,re-spectively.AccordingtoEq.(3),suchtransmissionmin-imumisrelatedtotheexcitationof(1,0)-modeSPPatFig.1.Opticalimageofthemetallicholearraywithastruc-tureof120×50(μm)andperiodicityof200μmonfusedsilicasubstrate.Thestructuralparametersofallsampleshave2%deviationfromthoseofdesignedstructures.April30,2011/Vol.9,Supplement/CHINESEOPTICSLETTERSFig.2.(a)Measuredtransmissionspectraofthestructures150×50(μm)withperiodicitiesof180,200and220μmonfusedsilicasubstrate,(b)Calculatedtransmis-sionspectraofthestructuresin(a).thesubstrate-metalinterface.TheresonantfrequencyofSPPattheair-metalinterfaceismuchhigherthanthatatthesubstrate-metalinterface,e.g.,thefrequencyof(1,0)-modeSPPatAl-airinterfaceis1.5THzforthesamplewithaperiodicityof200μm.ThelargeSPPfrequencydifferencebetweenair-metalandsubstrate-metalinterfaceshindersthecouplingefficiencyacrossthemetallichole,leadingtotransmissionminimumattheSPPfrequency.Thepeakpositionofthetransmis-sionshowsaslightredshift(i.e.,from0.63to0.58THz)astheperiodicityofthestructureincreasedfrom180to220μm.Weattributethetransmissionmaximumtothecontributionofhalf-wavelengthresonancefromthecut-offwaveguidemode(Fig.2(a)).Thepositionoftransmissionminima(orresonantfre-quencyofSPP)shiftedtolowfrequencywithaniasaresult,thehighfrequencysideofthewaveguidetransmissionprofilewaspossiblycutoffbytheperiodicity-relatedtransmissionminima.Thus,thefinaltransmissionprofileprovidesacheatingphe-nomenonwhichmakesitlookliketheshiftofthetrans-missionpeak.Inpreviousworks[12?14],thefrequenciesoftheSPPresonancecorrespondedtothepositionoftrans-missionminima,ratherthantransmissionmaxima.TheperiodicityindependenceoftransmissionpeakindicatesthattheSPPresonanceisnotthekeymechanismrespon-siblefortheenhancedtransmissionintheTHzregion.UsingtheFDTDmethod,numericalsimulationswereperformedonthesampleswhosegeometricalparametersweresettobethesameasthoseintheexperiment.ThesimulationresultsshowninFig.2(b)revealthattheyareingoodagreementwiththeexperimentalresults,ex-ceptforthepeaktransmissionintensities.ThesimulatedresultsalsoshowslightlyhigheramplitudetransmissionduetolosslesscharacteristicsofPEC.Inordertorecognizetheoriginalityofthetransmissionpeakfurther,anothersetofsamplesweredesignedandfabricated.Thistime,theperiodofholearrayswasfixedatd=200μm,andtheshapesoftherectangularholesweresetat50×50,100×50,120×50and150×50(μm),respectively.Thepolarizationoftheincidentwavewaskeptperpendiculartothelongedgeoftherectangularholes.Thenormalizedzero-ordertransmissionisshowninFig.3(a).Itisobviousthattheminimaoftransmis-sionarealllocatedatthesameposition,0.77and1.08THz,whichoriginatedfrom(1,0)-modeand(1,1)-modeSPP,respectively,atthesubstrate-metal(S/M)interface(Eq.(3)),asshowninFig.3(a).Thepositionsoftrans-missionmaximashowhole-shapedependence,andtheresonancefrequencyshiftedfrom0.61to0.72THz,withthelongedgelengthoftherectangularholesdecreas-ingfrom150to100μm.ItshouldbementionedthatweonlyvariedthelengthoftheedgeperpendiculartotheTHzwavepolarization,andthelengthoftheotheredgeaswellastheperiodicityofthearraysremainedsame.Thus,itiseasytoconcludethatitisthelocal-izedwaveguideresonances,ratherthanSPP,thatledtothetransmissionenhancement.Forthesampleconsist-ingof50×50(μm)rectangularapertures,becausethewavelengthoftheTHzsourceislargerthanthecut-offwavelengthoftheholewaveguide,thetransmissionistoolowtobedetectedinoursetup.Figure3(b)showsthecalculatedtransmissionspectraofthestructuresasthosemeasuredintheexperimentusingFDTDsimula-tion.Thereisagoodagreementofthepeakpositionandbandwidthbetweentheexperimentalresultsandtheoreticalsimulation.Fig.3.(a)Measuredtransmissionspectraofthestructures50×50,100×50,and150×50(μm),allwithperiodicityof200μmon(b)Calculatedtransmissionspectraofthestructurein(a).CHINESEOPTICSLETTERS/Vol.9,Supplement/April30,2011Fig.4.Thetransmissionspectraofthestructure150×50(μm)withperiodicityof200μmwithdifferentincidentangledeviatesfromthe(a)y-axisand(b)x-axis.Fig.5.Thetransmissionspectraofthestructure150×50(μm)withperiodicityof200μmwhenchangethepolarizationoftheincidentlightdeviatesfromthey-axis.Asanalyzedabove,thetransverselocalizedwaveguideresonanceledtotheextraordinarytransmission.Assum-ingthatthelengthsoftheshortandlongedgeoftherectangularholeareaandb,respectively,thetransmis-sionpeakatthefundamentalshaperesonancecanbewrittenasλres=2ne?b[21,22],wherenindexofthefundamentalwaveguidemodee?istheeffectiverelatedtotherefractiveindexofairandsubstrate,themagnitudeliesbetween1andnsubstrate.s[26].Here,nsistherefractiveindexoftheThewaveguideresonancefrequencyshiftstowardsthefrequencyof(1,0)-modeSPPonthesubstrate-metalin-terfacewiththedecreaseofthelengthofthelongedgeoftherectangularhole(Fig.3).Asaresult,thetrans-missionpeakprofilewillbestronglyaffectedbyspoof-SPP.Fortransmissionmeasurement,incidentlightcou-pledwiththespoof-SPPmodeofbothsidesofmetalfilm,buttheSPPfrequenciesonbothinterfacesdidnotover-lapatallinourcaseduetothelargeenergydifference.Asaresult,theexcitationofSPPledtolossoflighttransmission.Withthisphenomenon,itisreasonabletounderstandwhythemosttransmissionmaximumalwaysappearsonthelowerfrequencypartoftheSPP.Inourcase,SPPactsasa“band-stopfilter”forlighttransmis-sion,modifyingthewaveformofthelocalizedwaveguideresonance.WhenthefrequenciesofwaveguideresonanceandSPPwerecloseenough,thepositionofthetransmis-sionpeakwasdominatedbybothwaveguidemodeandSPPmode.Thetransmissionpeakofthestructureof100×50(μm)wasincomplete,whichwas“cut”bythe“SPPfilter.”WithreferringtothecoordinateshowninFig.1,lightincidentangledependenceofTHzwavetransmissionisinvestigated.Inthisstudy,theholearrayswithasizeof150×50(μm)andperiodicityof200μmwasused.Atfirst,wechangedtheincidentanglesalongthey-axis.Intheexperiment,whatwedidwastorotatethesamplealongthex-axis.Accordingtoconservationofmomentum,theincidentlightalsoprovidedanin-planemomentumforSPPexcitation,andEq.(3)canberewrittenas:λsp=λLR=(n+sinθ),(4)wherenistherefractiveindexofairorsubstrate.ItshouldbenoticedthatthewavelengthsofSPPexcita-tionareoverlappedcompletelywiththatofRayleighanomaliesatallconditionsforPECinaddition,bothofthemshowsameincidentangledependence.Bychangingtheincidentanglefrom0?(normalincident)to40?,Figure4(a)showsangledependenceofthetransmis-sionspectraofthestructure150×50(μm).Inaddition,thepositionof(1,0)-modeSPPonthesubstrate-metalinterfaceshiftedfrom0.77to0.58THz,withincidentanglesvaryingfrom0to40degree,whichisingoodagreementwiththepredictionfromEq.(5).Thetrans-missionmaximumpositionalsoshowedanegligible?shiftwhentheincidentanglewassmallerthan20.Astheincidentangleincreasedfurther,thetransmissionpeakseemstohaveshiftedtoalowerfrequencyduetotheoverlappeffectoftheSPP“filter”andwaveguidereso-nance.Theincidentangledependenceoftransmissionspectraprovidesevidencethatitisthelocalizedwaveg-uideresonance,andnottheSPPresonance,thathasledtotheenhancedtransmission.Next,wechangetheincidentanglesalongthex-axisbyrotatingthesamplealongthey-axis.Thiskindofrotationprovidesanin-planemomentumalongthex-direction,whichdoesnotaffectthe(1,0)-modeSPPandRayleighanomalyatthesubstrate-metalinterface.However,withtheincreaseoftherotationangle,thetransmittedenergyinthez-directiondecreases.Thede-creaseofenergyintransversewaveguideresonancecanweaketheresultispresentedinFig.4(b).Inthisstudy,wealsotaketheholearrays150×50(μm)withtheperiodicityof200μmasexamples.Intheexperiment,wechangedthepolarizationoftheincidentlightatnormalincidence.ThepolarizationoftheTHzwavewasintheXYplane.Whenthepolariza-tionoftheincidentlightdeviatedfromthey-axis,theApril30,2011/Vol.9,Supplement/CHINESEOPTICSLETTERSFig.6.Thesimulatedtransmissionandre?ectionspectraofthestructure150×50(μm)withperiodicityof200μmatnormalincidence.Fig.7.Calculatedelectricfielddistributionforthestructureof150×50(μm)withperiodicityof200μmunderexcitationfrequenciesat(a)0.61THz(waveguidemode)and(b)0.77THz(SPPfrequency).componentalongthex-axiswasnotzero.Forthex-directionpolarization,thecut-offfrequencywas3THz,muchhigherthantheoutputfrequenciesofourTHzsource.Hence,x-polarizedmodesarenon-propagatingwaves.Atthesametime,thedecreasingcomponentalongthey-axisresultsindecreasingtransmission.Thetransmissionamplitudedecreasesrapidlywiththein-creaseofrotationangle(Fig.5).ForaPEC,theskindepthofelectromagneticfieldiszero,orsay,thereisnolossinPECfilm.Withperi-odicalarraysofholesperforatedonthePECfilm,light-matterinteractioncanbedepictedbytheexcitationofaspoof-SPP,wherebytheperfectmetalinterruptedwithaperiodicalarrayofholesbehaveasifitisarealmetalinvisiblefrequencyregime.ThetransmissionminimumshowninFig.3showsthattheenergyatthespoof-SPPfrequencyisdissipatedinthefilm,whichisunreasonableforthePECfilm.Inordertoclarifythisphenomenon,wecalculatedthetransmissionandre?ectionspectrumofthearray150×50(μm)withtheperiodof200μmatnormalincidentradiationbyFDTDsimulation(Fig.6).Thepeakofre?ectanceappearedat0.77THz,cor-respondingtotransmissionminimum(theresonantposi-tionof(1,0)-modeSPPatthesubstrate-metalinterface).Duringre?ectionspectrasimulationbasedonFDTD,weonlycollectedthedatafromzero-Rayleighanomalycanberuledoutforthecontributiontothere?ectionpeakatλsp(λR)becausethepassingofforderpropagatesalongthemetallicgratingsurface,andhasnocontributiontothezero-orderre?ection.There-fore,webelievethattheexcitationofSPPatthemetal-substrateinterfaceenhancesre?ection,evenleadstototalre?ection,andasaresulttransmissionspectrumshowsaminimum.AlthoughtheresonantfrequencybetweenRayleighanomalyandSPPisoverlappedcompletelyforthePECstructure,theyshowdifferentcontributionstothezero-orderre?ectionspectrum,sothatwecanidentifythein?uenceonthetransmissionandre?ectionspectra.Asmentionedabove,transversewaveguideresonanceplaysadominantroleintheenhancedtransmissioninTHzregime.Tounderstandthephysicalprocesslead-ingtotheenhancedtransmissionandmechanismsofthewaveguideresonanceinsidetherectangularholes,wecal-culatedtheelectricfieldamplitudedistributioninsidetheholeatresonantfrequencyof0.61THz(waveguidemode)and0.77THz(Rayleighanomaly)forthestructureof150×50(μm)withperiodicityofd=200μm(Figs.7(a)and(b),respectively).Astheincidentlightfrequencyison-resonantwiththewaveguidemodelocatedat0.6THz,theelectricfielddistributioninsidetheholeisnothomogeneous.Itisclearthattransversewaveguideres-onanceisnotaconventionalwaveguideresonance,butahybridcharacter:themodeinvertical(x-axis)directionisatypicalwaveguidemode,butislaterallyevanescentandconfinedontheedgeoftheholeinthehorizontal(y-axis)direction.ThetransversewaveguidemodebehaveswithaSPP-likecharacter.However,itisnotapropa-gatingSPP,becauseitislocalizedinsidemetallicholeandshowsindividualhole-shapedependence.Previousstudiescalledthisthe“cavitysurface-plasmon”(CSP)or“waveguidesurface-plasmon”(WSP)mode[20,27,28].Meanwhile,withtheexcitationattheSPPfrequencyof0.77THz,amplitudesofelectromagneticfielddistribu-tioninsithisresultisreason-ablebecausealmost100%incidentlightisre?ectedoutat0.77THz,andnolightpenetrateintothestructure.Inconclusion,theroleofthewaveguideresonanceandSPPinextraordinarytransmissionhasbeeninvestigatedintheTHzregime.Forthinmetalfilmwithperiodicarraysofsubwavelengthrectangularholesonsubstrate,thephysicalmechanismoftheextraordinarytransmis-sioninTHzregioncanbeunderstoodas:transversewaveguideresonanceismodulatedbytheexcitationofSPP;shaperesonancedominatsthemaximaofthezero-ordertransmission,andtheexcitationofSPPrelatedtoperiodofthearraysactsasa“band-stopfilter”toshapetheprofileoftheSPPalsoaffectsthepositionoftransmissionpeakwhenthefrequencybe-tweenwaveguideresonanceandSPPiscloseenough.We包含各类专业文献、高等教育、行业资料、生活休闲娱乐、外语学习资料、专业论文、幼儿教育、小学教育、应用写作文书、【EastFDTD】The transmitted properties of terahertz wave through metallic hole arrays07等内容。