We investigate numerically the transmission properties of a thin sinusoidally corrugated metal film bounded by two different dielectrics in the context of the experiment of Gruhlkeet al (1986). We study the dominant contributions from both the propagating and evanescent plane waves. A comparison with the experimental results reveals that the decisive role in cross coupling is played by the evanescent waves emitted by the molecular dipole. We extend our studies to different corrugation amplitudes and widths to show their effect on transmission.

We present exact numerical results for a symmetric layered medium (prism/Ag film/nonlinear dielectric/Ag film/prism) where the middle dielectric slab is assumed to have a saturation-type nonlinearity. We show bistable behaviour in the power dependence of the reflectivity ofp-polarized light under the condition when coupled surface modes are excited in the structure. Moreover, we study the effect of saturation on the bistable behaviour to show that multivalued character is inhibited by saturation effects. The field distributions corresponding to the minimum reflectivity states of the nonlinear structure are also presented.