The effect of a superconducting surface layer on the optical properties of a dielectric photonic composite

Abstract

The effect of a strongly anisotropic superconducting surface layer on the transmittance, reflectance and absorptance of a one-dimensional, layered dielectric composite with periodically alternating, isotropic constituents for linearly polarized, normally incident electromagnetic radiation is studied both analytically and numerically. The underlying model of the electric permittivity of the superconducting constituent permits photonic excitation at frequencies both below and above the superconductor pair breaking frequency as well as thermal and normal scattering right up to the superconductor critical temperature. The optical properties addressed reveal traits such as band-like patterns of the transmittance and reflectance, but also step-like or smeared-out patterns of the reflectance and absorptance, displaying a marked reference to the particular type of polarization by virtue of the anisotropy of the superconducting layer covering the dielectric composite. Thus, in switching from transverse electric to transverse magnetic polarization, the maximum optical selectivity can become gigantic, given an appropriate thickness of the superconducting layer, with a moderate dependence on temperature. This fact offers unique possibilities regarding practical applications of such a novel photonic composite as an efficient polarization filter for electromagnetic radiation tunable via the thickness of the covering layer and temperature.