摘要
Couplingefficiencybetweenthelocalizedsurfaceplasmons(LSPs)ofmetalnanoparticles(NPs)andincidentlightdominatesthesensitivitiesofplasmon-basedsensingspectroscopiesandimagingtechniques,e.g.,surfaceenhancedRamanscattering(SERS)spectroscopy.ManyendogenousfeaturesofmetalNPs(e.g.,size,shape,aggregationform,etc.)thathavestrongimpactsontheirLSPshavebeendiscussedindetailinpreviousstudies.Here,thepolarization-tunedelectromagnetic(EM)fieldthatfacilitatestheLSPcouplingisfullydiscussed.Numericalanalysesonwaveguide-basedevanescentfields(WEFs)coupledwiththeLSPsofdispersedsilvernanospheresandsilvernano-hemispheresarepresentedandtheapplicabilityoftheWEF-LSPstoplasmon-enhancedspectroscopyisdiscussed.ComparedwithLSPsunderdirectlightexcitationthatonlyprovide3–4timesenhancementoftheincidencefield,theWEF-LSPscanamplifytheelectricfieldintensityabout30–90times(equalingtheenhancementfactorof10~6–10~8inSERSintensity),whichiscomparabletotheEMamplificationoftheSERS'hotspot'effect.Importantly,thestrongestregionofEMenhancementaroundsilvernanospherescanbemodulatedfromthegapregiontothesidesurfacesimplybyswitchingtheincidentpolarizationfromTMtoTE,whichwidelyextendsitssensingapplicationsinsurfaceanalysisofmonolayerofmoleculeandmacromoleculedetections.Thistechniqueprovidesusauniquewaytoachieveremarkablesignalgainsinmanyplasmon-enhancedspectroscopicsystemsinwhichLSPsareinvolved.
出版日期
2017年05月15日（中国期刊网平台首次上网日期，不代表论文的发表时间）
