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1、Leakymodesofaleft-handedslabA.MoreauLASMEA,UMRCNRS6602,Universit´eBlaisePascal,24avenuedesLandais,63177Aubi`ere,France.D.FelbacqGESUMRCNRS5650,Universit´edeMontpellierII,Bat.21,CC074,PlaceE.Bataillon,34095MontpellierCedex05,France.Usingcomplexplaneanalysisweshowthatle
2、ft-handedslabmaysupporteitherleakyslabwaves,whicharebackwardbecauseofnegativerefraction,orleakysurfacewaves,whicharebackwardorforwarddependingonthepropagationdirectionofthesurfacewaveitself.Moreover,thereisageneralconnectionbetweenthereflectioncoefficientoftheleft-handed
3、slabandtheoneofthecorrespondingright-handedslab(withoppositepermittivityandpermeability)sothatleakyslabmodesareexcitedforthesameangleofincidenceoftheimpingingbeamforbothstructures.Manynegativegiantlateralshiftscanbeexplainedbytheexcitationoftheseleakymodes.Keywords:Le
4、ft-handedmaterials,leakymodes,complexplaneanalysis1IntroductionLeft-handedmaterials[1]havelongbeenconsideredatheoreticaloddity.Sinceithasbeendemonstratedthattheycouldbeproducedusingmetamaterials[2],theyhaveattractedmuchattention.Thebasicphysicsofleft-handedmaterials(L
5、HM)istrulyexoticandhasbeencompletelyignoreduntilrecently,itrenewsthephysicsoflamellarstructurestotheextendthatabareslabofLHMexhibitsmanysurprizingproperties:itcanforinstancesupportunusualguidedmodes[3,4]orbehaveasaperfectlens[5].Inthispaper,westudytheexoticpropertieso
6、fthedifferenttypesofleakywavessupportedbyaleft-handedslab.arXiv:0704.0414v2[physics.optics]5Aug2008Giventheimportanceoftheleft-handedslabforbothfundamentalandappliedworks,thereisobviouslyaneedforaclearunderstandingoftheseproperties.Weparticularlyshowthattwotypesofleaky
7、wavesaresupportedbysuchastructure(i)leakyslabwaveswhicharealwaysbackwardduetonegativerefractionand(ii)leakysurfacewaveswhichdonotexistforaright-handedslabandwhichcanbebackwardorforward.Theexcitationofthesemodesleadstopositiveornegativegiantlateralshifts,thelatterbeing
8、ratherexotic[6].12LeakymodesandgiantlateralshiftsAleakymode[6]isasolutionofthewaveequationwhichverifiestherelationdispersiono