Plasmonic properties of metal nanoislands: Practical guide

Abstract

We propose a simple approach to describe plasmonic properties of a metal hemisphere placed on a dielectric substrate and covered by another dielectric. Very simple analytical expressions and numerical data presented allow avoiding numerical calculations in finding the spectral position of the surface plasmon resonance and the dispersion of the polarizability of the hemisphere. The expressions are obtained using semi-analytical solution of the related problem in the quasistatic approximation. They are valid for most of the metals and for a wide variety of dielectric substrate and cover materials. The maps allowing to find the surface plasmon resonance wavelength and spectral dispersion of the polarizability of Ag, Au, Cu, and Al hemispherical nanoparticles are also presented. The maps are plotted in the coordinates of the substrate and the surrounding media dielectric permittivity. The results of the study can be applied to describe the polarizability of isolated or weakly interacting metal nanoislands and metal island films.