Theory of light scattering by surface polaritons in a composite medium

We develop a theory of light (or Raman) scattering by surface polaritons propagating along an interface of a composite medium bounded by vacuum. The Maxwell–Garnett formulation is used to model the effective dielectric function of the composite medium. The differential scattering cross section for surface polaritons is presented. Linear response theory is applied to calculate electric field fluctuations by utilising the fluctuation dissipation theorem. It is illustrated that the dispersion relation, electric field fluctuations, damping function and the differential scattering cross section are strongly dependent on the filling factor, f, which is a measure of the constituents of the composite medium. A composite medium of KCl and Ag bounded by vacuum is used to illustrate our results.