Analysis of dichroism in the electromagnetic response of superconductors

The absorption of polarized light in superconductors is studied within the framework of the Bogolubov-de Gennes approach to inhomogeneous superconductors in magnetic fields. Several mechanisms which give rise to a polarization-dependent absorption (i.e., dichroism) in superconductors are analyzed in detail. The relation to the absorption of unpolarized light in superconductors and to the absorption of polarized light in normal conductors is investigated and several effects, not known from either of these cases, are found. These effects arise from the interplay of broken chiral symmetry, which produces dichroism, with the superconducting coherence. One potential source for dichroism, namely spin-orbit coupling, is investigated numerically for a simple model superconductor. [S0163-1829(98)01122-9].