Plasmon-polariton excitations on surfaces with fluctuating impedance

Abstract

Scattering of surface TM polarized plasmon-polariton waves by a finite strip of the flat metal-vacuum interface with randomly fluctuating impedance is studied. We analyze the integral equation governing the scattering of the incident surface plasmon-polaritons, which is valid for arbitrary scattering intensity and arbitrary dissipation in the conductive medium. The strength of the scattering is shown to be controlled not only by the parameters of the fluctuating impedance (dispersion, correlation radius, the length of inhomogeneity region) but also crucially depends on the conductivity of the metal. If the scattering operator norm is small as compared to unity (weak scattering limit), the incident surface plasmon-polariton is mainly scattered into the vacuum, thus losing its energy for excitation of non-isotropic bulk quasi-Norton waves. Under condition of strong scattering, the radiation of waves into the free space is highly suppressed, and the incoming surface plasmon-polariton is almost ideally backward-reflected from the inhomogeneous part of the interface.