THEORETICAL AND EXPERIMENTAL INVESTIGATION OF NONLINEAR FARADAY PROCESSES IN DILUTED MAGNETIC SEMICONDUCTORS

Nonlinear Faraday processes in diluted magnetic semiconductors are theoretically and experimentally investigated through the analysis of the modifications of the intensity, the polarization direction, and the phase of a high-intensity arbitrarily polarized laser beam. Calculations demonstrate that the nonlinear Faraday processes are decoupled from Kerr effects when the propagation wave vector is in the (1, 1, 1) direction with respect to the crystal axes. Experiments performed in such a configuration in Cd0.76Mn0.25Te confirm this analysis and show photoinduced polarization rotations and phase changes proportional to the magnetic field that saturate when the laser intensity is increased beyond a certain value. The large nonlinear susceptibilities derived for the material show that the nonlinear Faraday processes could overcome two-photon absorption and Kerr effects for magnetic fields of the order of a few tesla.