Polarization controlled nonlinear transmission of light through semiconductor microcavities

We report on a pronounced nonlinear optical effect in a GaAs microcavity operating in the strong-coupling regime: cavity transmission in circular polarization is found to be much stronger than in linear polarization. This behavior has its origin in the spin-dependent repulsive interaction between exciton polaritons. Quantitative analysis allows estimating the strength of interaction between polaritons with parallel spins. The observed effect shows the potentiality of microcavities for circular polarization sensing essential for transmission of polarization encoded signals.