Polarization and depolarization in scattering of cavity polaritons

We consider theoretically the elastic scattering of two exciton polaritons having opposite wave vectors in a planar microcavity. We derive the scattering amplitudes accounting for the vector polarization of polaritons and the interference of different scattering channels. We obtain a nontrivial dependence of the scattering amplitudes and the polarizations on the scattering angle and polarization of initial states. Generation of polariton spin currents as a result of scattering of linearly polarized polaritons is predicted. We also describe depolarization of exciton polaritons due to their scattering and show that it may be complete in certain scattering directions. This analysis provides a basis for engineering of spin- and electric field-sensitive optical logic gates based on exciton polaritons.