Inverse Faraday Effect in Superconductors with a Finite Gap in the Excitation Spectrum

Abstract

The inverse Faraday effect (generation of a time-independent magnetic moment under the action of a circularly polarized electromagnetic wave) in mesoscopic superconducting samples with a finite gap in the excitation spectrum is analytically described. Within the modified time-dependent Ginzburg–Landau theory (Kramer–Watts-Tobin equations) for thin superconducting disks, it is shown that the temperature dependence of the optically induced magnetic moment is nonmonotonic in a wide range of parameters and contains a maximum. This maximum is due to the dephasing between the spatial oscillations of the magnitude and the phase of the order parameter, which arises with a decrease in the temperature and, correspondingly, in the characteristic relaxation time of perturbations in the superconducting condensate.