Nonlinear magneto-optic Kerr effect in semiconductor microcavities

The photo-induced modifications of the strong magneto-optic Kerr effect have been studied in a semimagnetic semiconductor microcavity operated in the strong coupling regime. These are traced to the saturation and many body interaction blue shift of the exciton transition frequency, which result in a photo-induced reduction of the effective exciton–cavity coupling. Its impact is most striking in the case of initially tuned microcavity, where a modification of the exciton–cavity coupling results in photo-induced polarization rotations of about 30 degrees for laser fluences as low as 1 μJ/cm2 and magnetic field intensities of 0.2 T.