Modified Fresnel equations for the case of oblique incidence on an isotropic gyrotropic medium

Modified Fresnel equations for the oblique incidence of plane elliptically polarized electromagnetic waves on a flat boundary of a non-absorbing isotropic gyrotropic medium have been obtained. We have taken into account the influence of near-surface inhomogeneity of the matter. The derived relationships allow determining the intensity, degree of ellipticity, and the angle defining the orientation of the polarization ellipse of the reflected wave, as well as the intensities of two circularly polarized waves propagating at different angles in the isotropic gyrotropic medium. It is shown that considering the optical activity of the medium and its near-surface layer leads to significant differences between the modified and classical Fresnel equations.