Resonant Faraday rotation effect in semimagnetic and nonmagnetic microcavities

Abstract Rotation of the polarization plane of a linearly polarized light (Faraday rotation, FR) at the quantum-well (QW) exciton resonance frequency is greatly amplified if the exciton is coupled to the cavity photon mode due to multiple round-trips of light inside the cavity. Simultaneously, a redistribution of the energy of the electromagnetic wave between linear and circular polarizations takes place. In the empty semimagnetic cavity this leads to the splitting of the cavity-mode dispersion curves in right- and left-circular polarizations. The purely electromagnetic theory of these effects has been constructed. Experimentally, resonant excitonic Faraday rotation achieves 3° in reflection in the microcavities studied.