Chapter 6 - EM enhancements and plasmon resonances: examples and discussion

Abstract

This chapter discusses the physical meaning of the results for a few specific geometries of interest, a plane, an ellipsoid in the electrostatics approximation, and a sphere (Mie theory) in the context of surface-enhanced Raman scattering (SERS) and related plasmonic effects. The main goals of this chapter are: to understand more quantitatively the link between the electromagnetic (EM) enhancements in SERS or surface-enhanced fluorescence (SEF) and the underlying localized surface plasmon (LSP) resonances of the substrate; and to understand in more detail the characteristics of the LSP resonances and how they relate to the geometry and other characteristics of the substrate. It helps one identify the various factors governing the magnitude of the EM enhancements in SERS and SEF, and provides and discusses simple examples of EM predictions for a few model systems. It is organized around those examples. It discusses the case of planar surfaces, which is arguably not very relevant to SERS, but provides a good introduction to nonradiative effects, relevant to SEF. Furthermore, it provides a synthetic summary of the various factors affecting the plasmon resonances and EM enhancements.