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

A combined Ag nanoparticle with an insulating or conductive layer structure has been designed for molecular detection using surface enhanced Raman scattering microscopy. Optical absorption studies revealed localized surface plasmon resonance, which shows regular red shift with increasing environmental dielectric constant. With the combined structure of surface enhanced Raman scattering substrates and rhodamine 6G as a test molecule, the results in this paper show that the absorption has a linear relationship with the local electromagnetic field for insulating substrates, and the electrical property of the substrate has a non-negligible effect on the intensity of the local electromagnetic field and hence the Raman enhancement.