Reflection of electromagnetic waves from a periodically rough multilayered surface

Abstract

The analysis of Cavalcante et al.[ J. Opt. Soc. Am. B4, 1372 ( 1987)], which treats the reflectivity and polariton coupling problem of p-polarized radiation incident on a thin metallic film with a grating underlayer, is extended by considering the placement of a thin dielectric film on top of the metallic film. In general, the numerical results from the Rayleigh–Fano equations for extremely thin dielectric overlayers of the order of 100 Å are comparable with those found by Cavalcante et al., except that the field enhancement peaks and reflectivity dips are shifted slightly toward higher angles of incidence. It is observed that the two-mode polariton interaction is nearly quenched to a single mode as the thickness of the metal thin-film grating is increased and that the reflectivity dips and field enhancement peaks are decreased uniformly as the thickness of the dielectric overlayer is increased. An increased peak behavior for the reflectivity and field enhancement interactions is also found as the metal film corrugation strength or the dielectric constant of the overlayer is increased; however, a limiting behavior is observed for further increases in the dielectric constant.