Scattering matrix of elliptically polarized waves

Abstract

We analyze the scattering of elliptically polarized plane waves normally incident at the planar interface between two different materials; we consider two cases: dielectric-dielectric and dielectric-conductor interfaces. The scattering $S$ matrix in both cases is obtained using the boundary conditions and Poynting's theorem. In the dielectric-dielectric case we write $S$ using two different basis, the usual $xy$ and a rotated one. For the dielectric-conductor interface, the use of the rotated basis together with an energy balance argument leads us, in a natural way, to construct a unitary $S$ matrix after recognizing the need to introduce two equivalent parasitic channels due to dissipation in the conductor, and the transmission coefficient into these parasitic channels measures the absorption strength.