Polaritons at Surfaces

Abstract

We calculate the reflectivity of light incident upon the exposed face of a semi-infinite crystal, using the point-dipole model. This requires an accurate solution for the polariton modes near the crystal surface. The variation of the Lorentz local field, caused by the surface, is included in the calculations. The boundary conditions for the polariton modes are derived rigorously. This represents the first rigorous microscopic solution of polariton modes near ideal surfaces.