Theory of nonlinear guided and surface plasmon-polaritons in dielectric films

Calculations are presented for the dispersion relations of nonlinear plasmon-polariton modes in a layered dielectric structure consisting of a film bounded on each side by another medium. At least one of the media is a metal or semiconductor (such as InSb) with a real, isotropic, frequency-dependent dielectric function, characteristic of an electron plasma. In addition, both media may have a Kerr-type nonlinearity in their dielectric functions. Hence the resulting plasmon-polaritons, which we study in s polarization, are nonlinear and are found to occur in multiple branches. The theory is illustrated by numerical solutions of the dispersion relations for several geometries and physical parameters, and a comparison is made with previous plasmon-polariton results for linear dielectric media as a special case.