An absorbing mode at the dielectric-conductor interface: oblique incidence.

We apply Poynting's theorem to the dielectric-conductor interface to determine the intensity of the absorbing mode (parasitic channel), when plane waves incide with an angle of incidence. By applying boundary conditions we are able to describes the scattering at the interface by means of a subunitary scattering matrix. The energy balance equation allows to determine the lack of unitarity (absorbance) as a function of the frequency and the angle of incidence. Also, it allows to write a unitary scattering matrix which contains the subunitary one and a single parasitic channel with transmission intensity given by the absorbance. [ABSTRACT FROM AUTHOR]