Scattering of surface plasmon polaritons by one-dimensional inhomogeneities

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 defects considered 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 the backward or forward (or both) direction, depending on the defect width.