THE REFLECTIVITY OF A FILM WITH A GRATING IN CONTACT WITH A SEMIINFINITE BIMETALLIC SUPERLATTICE

We study the influence of a semi-infinite bimetallic superlattice on t he 'excitation' of surface polaritons appearing in a film with a grati ng surface. The transfer-matrix formalism and the Rayleigh-Fano approa ch are applied to study the optical response for p-polarized light. We analyse the reflectivity and the dispersion relation of the surface p lasmon-polaritons, considering Al and Mg for the semi-infinite superla ttice and Mg for the film. The 'optical' dispersion relation of surfac e plasmons is constructed using the minima of the reflectivity. This r elation shows a dependence on the corrugation strength such that, as t his corrugation grows. the corresponding curve shifts to lower frequen cies.