Stimulated spin dynamics of polaritons in semiconductor microcavities

Time-resolved polarization spectroscopy of polariton pair scattering in semiconductor microcavities enables complete measurement of the polariton spin dynamics. In addition to spin-preserving interactions previously reported, we observe two additional even stronger scattering processes, which mix polaritons of opposite spin. Because of the polaritons' bosonic character, this results in the stimulation of spin flips. Such mechanisms should allow realization of spin-sensitive interferometers.