Influence of local environment on the intensity of the localized surface plasmon polariton of Ag nanoparticles

A combined Ag nanoparticle with an insulating or conductivelayer structure has been designed for molecular detection usingsurface enhanced Raman scattering microscopy. Optical absorptionstudies revealed localized surface plasmon resonance, which showsregular red shift with increasing environmental dielectricconstant. With the combined structure of surface enhanced Ramanscattering substrates and rhodamine 6G as a test molecule, theresults in this paper show that the absorption has a linearrelationship with the local electromagnetic field for insulatingsubstrates, and the electrical property of the substrate has anon-negligible effect on the intensity of the local electromagneticfield and hence the Raman enhancement.