Surface electromagnetic waves on metals and polar insulators: some comments.

The important parameters governing the propagation of surface electromagnetic waves (SEW) on metals or polar insulators have been theoretically investigated. General approximations for the propagation distance, decay distance, and penetration depth are presented in summary tables. It is found that the propagation distance of SEW can be used to study overlayer materials on metals, that the penetration depth of SEW fields into a metal is governed by the classical skin depth at low frequencies and by the plasma frequency in the visible wavelength region, that surface phonons can propagate over a centimeter on PbS, PbTe, and ferroelectrics, and that the propagation distances of SEW increase with decreasing temperature.