Theory of Light Emission from Dipole Moments Induced by Localized Plasmons in Metal Nanostructures

Abstract

A theory is derived for light emission by localized plasmon excitation by developing our existing theory of localized bulk and surface plasmons for metal nanostructures to consider the retardation of the scalar potentials. Using the retarded scalar and vector potentials, the electromagnetic fields that are emitted by the electric dipole moments induced by localized plasmons are derived, which in turn give the frequency and angular dependences of the intensity of the light that is emitted from the metal nanostructures. The emitted light intensities are analytically calculated for metal nanospheres with step function-like electron densities at their surfaces when electric fields and electrons are incident on those surfaces. The model calculations show that localized surface plasmon excitation only contributes to the light emission because of the coupling between localized bulk and surface plasmons. [DOI: 10.1380/ejssnt.2014.431]