Polariton spin carries the combination of the exciton and the photon spin, which is manifested in the circularly polarized emission degree in a III-V quantum wells microcavity system. Relaxation process of such spin system is a complex subject since
it involve upper or lower polariton branch, resonant or non resonant polariton excitation process and if the particles are in strong or weak coupling regime. We present here experimental polariton spin Faraday rotation time measurement in GaAs single quantum well microcavity, using time resolved polariton photoluminescence by resonant excitation process in a pump-probe system.
