Plasmon dispersion relation of Au and Ag nanowires

Abstract

We have studied surface plasmon modes on silver and gold nanowires of a fixed cross section and different lengths, produced by electron beam lithography. The optically excited modes are determined by extinction spectroscopy and can be interpreted in terms of standing plasmon polariton waves. The eigenfrequencies are found to follow a dispersion relation similar to that for a planar metal/dielectric interface.