手性metamaterials的非对称传输特性-研究

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1、手性Metamaterials的非对称传输特性研究AbstractMetamaterialscanachieveuniqueelectromagneticpropertiesthatcouldnotbefoundinnaturalmaterials.Manipulatingpropagationofelectromagneticwavesefficientlybasedonmetamaterialshavealwaysbeenregardedasahottopic.Inrecentyears,met

2、amaterialscombinedwithotherresearchdirectionsbecomesancutting-edgeinterdiscipline,forexample,acombinationofchirality.Chiralityisapurelygeometricdescriptionofthesymmetry,referringtothestructureitselflackofgeometricsymmetry.In2006,anewandimportantelectro

3、magnetismeffect-circularconversiondichroismwasfoundbyN.Zheludevinplanarchiralmetamaterials,resultinginamacroscopicalasymmetrictransmissionphenomenon.Inthisdissertation,planarmetamaterialswillbetheoreticallyandexperimentallystudiedtoachieveasymmetrictra

4、nsmissionsandmanipulatepolarizationstatesofelectromagneticwaves.Theresearchshowssignificantimportanceofachievingultra-thin,multi-bandmetamaterial-basedpolarizationdevices.Themainresearchtopicsandinnovativeachievementsgainedareasfollows:1.Weproposeadual

5、-bandasymmetrictransmissionforforwardandbackwardpropagatinglinearlypolarizedwavesinabilayeredchiralmetamaterial.Simulatedandmeasuredresultsshowthatthebilayeredchiralmetamaterialcanachievecross-polarizationconversionwithanefficiencyofover90%forbothy-and

6、x-polarizedwaves.Theproposedmetasurfacecanberegardedasanultrathinpolarization-controlledswitchthatiseasilyswitchedon/offbychangingalinearlypolarizedwavetoitsorthogonalcomponent.2.Basedonthedesignmethodofmetamaterialsshowingasymmetrytransmissions,twoTHz

7、asymmetrytransmissiondevicesforlinearpolarizationshavebeenproposed.ThedesignedTHzdevicesbasedonplanarchiralmetamaterialshavemanyadvantagesincludingsimplestructure,easyfabricationandlowcost.3.Wedemonstrateakindoflinearpolarizationrotatorandinvestigateit

8、sopticalpropertiesbyuseoftheoreticalanalysisandelectromagneticsimulations.Thisstructurehasahightransmissionandthepolarizationrotationangleofthetransmittedwaveisstronglydependentonthestructure’stwistangle,whichopensabrightperspectiveinco