A hybrid plasmonic waveguide for subwavelength confinement and long-range propagation.pdf

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1、LETTERSAhybridplasmonicwaveguideforsubwavelengthconfinementandlong-rangepropagationR.F.OULTON,V.J.SORGER,D.A.GENOV,D.F.P.PILEANDX.ZHANG*NSFNanoscaleScienceandEngineeringCenter,3112EtcheverryHall,UniversityofCalifornia,Berkeley,California94720,USA*e-mail:xiang@

2、berkeley.eduPublishedonline:11July2008;doi:10.1038/nphoton.2008.131Theemergingfieldofnanophotonics1addressesthecriticalchallengeofmanipulatinglightonscalesmuchsmallerthanthewavelength.However,veryfewfeasiblepracticalapproachesexistatpresent.Surfaceplasmonpolar

3、itons2,3areamongthemostpromisingcandidatesforsubwavelengthdopticalconfinement3–10.However,studiesoflong-rangesurfaceplasmonpolaritonshaveonlydemonstratedopticalyconfinementcomparabletothatofconventionaldielectricwaveguides,becauseofpracticalissuesincludingoptic

4、allosseszhandstringentfabricationdemands3,11–13.Here,weproposeanewapproachthatintegratesdielectricwaveguidingwithplasmonics.Thehybridopticalwaveguideconsistsofaxdielectricnanowireseparatedfromametalsurfacebyananoscaledielectricgap.Thecouplingbetweentheplasmon

5、icandwaveguidemodesacrossthegapenables‘capacitor-like’Figure1Thehybridopticalwaveguide.Adielectriccylindricalnanowire23energystoragethatallowseffectivesubwavelengthofpermittivity1canddiameterdisseparatedfromametallichalf-spaceoftransmissioninnon-metallicregio

6、ns.Inthisway,surfacepermittivity1mbyananoscaledielectricgapofpermittivity1dandwidthh.plasmonpolaritonscantraveloverlargedistancesTheuppermediumisadielectricofpermittivity1d.1c¼12.25(GaAs)and(40–150mm)withstrongmodeconfinement(rangingfrom1d¼2.25(SiO2)atthetelec

7、ommunicationswavelengthl¼1,550nm.Thel2/400tol2/40).Thisapproachisfullycompatiblewithmetallicregionissilverwithapermittivityof2129þ3.3i(ref.24).Thecentresemiconductorfabricationtechniquesandcouldleadtotrulyofthecylinderdefinestheorigin(x¼y¼0).nanoscalesemicondu

8、ctor-basedplasmonicsandphotonics.Theneedforfast,compactandefficientlightsourcesanddetectorswithhighspatialandtemporalresolutionhasmotivatedresearchintoopticalstructurescapableofguidingprop