Phase measurements of surface electromagnetic waves on silver with excitation through the substrate

Surface electromagnetic waves are excited in the visible and near-IR regions of the spectrum, and interference measurements are performed. Their excitation is effected by a helium-neon laser (3.39, 1.15, and 0.63 µm) on the interface between air and a silver film of thickness 100 µm deposited on a substrate in the form of a prism of fused quartz. The exciting radiation is supplied from the substrate side in a regime of total internal reflection in the prism on the edge of the silver film. The wave vector of the surface electromagnetic wave investigated is determined from the results of phase measurements. The dependence of the efficiency of the excitation of surface electromagnetic waves on the angle of incidence of the exciting radiation onto the substrate is investigated. The real part of the dielectric function of the silver film is calculated.