MetaMaterials

METAMATERIALSCalebHughesHassanIsmailBrettMcCutchanECIV30311/30/2010Scope•WhatareMetamaterials•HowTheyWork•Types•Applications•RecentAdvancesWhatareMetamaterials?Engineered(attheatomiclevel)materialsthathaveuniquepropertiesnotfoundinnatureduetothearrangementanddesignoftheirconstituentsNOTE:THEPROPERTIESARETHATOFTHEENTIREARRANGEMENTANDNOTTHECONSTITUENTSTHEMSELVES“Meta”=above,superior,beyondSomeHistory•TheoreticaldesignbyVictorVeselagoin1968–Predictedmetamaterialsactinexactoppositemannerthannaturalmaterials(likenegativerefractiveindex)•Dr.JohnPendryshowedpracticalmethodofmakingmetamaterialsin1999V.G.VeselagoSirJohnPendry~ece695s/Lectures/Lecture_15.pdfHowDoesitWork?Normally,wavespropagateandinteractwithdifferentmediaaccordingtoSnell’sLawMetamaterials“Grab”wavesandsmoothlyredirectsthemduetonegativeindexofrefractionMaterialunitsmustbesmallrelativetothewavelengthbeingmanipulated•Electromagnetic–Transversewaves•Acoustic–Longitudinalwaves•Seismic–TransverseandLongitudinalwavesElectromagneticMetamaterialsNegativeRefractiveIndex•Antennas–Negativeindexofrefractionmeansmorewavebendingwhichmeanssmallerantenna(fewmm)―Candoublefrequencyrange―IncreaseradiatedpowerElectromagneticMetamaterials•Invisibility–VisiblelightwavesmustbemanipulatedCloakONCloakOFF~ece695s/Lectures/Lecture_16.pdfAcousticMetamaterials•Acousticwavesaredifferentthanelectromagneticwaves–LongitudinalwavesratherthanTransversewaves•Commonphysicalconceptsofwaves–Wavevector–Waveimpedence–Powerflow•NegativeRefractiveindex–NegativeMassDensity–NegativeBulkModulusRefractiveindexBulkModulusMassDensityAcousticMetamaterials•SoundproofRoom•InvisibleSubmarines(SonarBlocking)•SeismicMetamaterials-Negatethedestructiveeffectofseismicwavesonsurfacestructures-Requiresthedecouplingoflongitudinalpressurewavesandtransverseshearwaves,redirectingthemaroundacylindricalmetamaterialcloakCreationofMetamaterials•ContactPhotolithographyusedforlargernanomaterials•ElectronBeamLithographyusedforsmaller,moredetailedstructures://en.wikipedia.org/wiki/File:Left-handed_metamaterial_array_configuration.jpgLimitations•Smallwavelengthsrequireverysmallunits•Mustbeabletohandlerangeofwavelengthsforsomeapplications–FrequencySelectiveSurfaces(FSSakaTunable)—Nanophotonics&MetamaterialsECE695s~ece695sD.R.SmithatDukeUniversity—~drsmith/pubs_smith.htmQuestions?