Scattering of surface plasmon polaritons by one-dimensional inhomogeneities

TL;DR

This paper theoretically investigates how one-dimensional surface defects affect the scattering of surface plasmon polaritons, revealing how defect type and parameters influence energy direction and scattering behavior.

Contribution

It introduces a combined Rayleigh and modal expansion approach to analyze scattering by relief and permittivity defects on surfaces.

Findings

Radiated energy is forward-directed for impedance defects.

Relief defects can radiate energy backward or forward depending on defect width.

Transmission, reflection, and scattering depend on defect parameters.

Abstract

The scattering of surface plasmons polaritons by a one-dimensional defect of the surface is theoretically studied, by means of both Rayleigh and modal expansions. The considered defects are either relief perturbations or variations in the permittivity of the metal. The dependence of transmission, reflection and out-of-plane scattering on parameters defining the defect is presented. We find that the radiated energy is forwardly directed (with respect to the surface plasmon propagation) in the case of an impedance defect. However, for relief defects, the radiated energy may be directed into backward or forward (or both) directions, depending on the defect width.