Polariton-polariton scattering in semiconductor microcavities: Distinctivefeatures and similarities to the three-dimensional case

Polariton-polariton scattering has been measured in a GaAs-based microcavit y by a c.w. polarized photoluminescence technique using circularly and elli ptically polarized resonant excitation into the lower polariton (LP) branch . The scattering has been found to be strongly enhanced when the singlet bi exciton state is allowed as an intermediate one, i.e., under elliptically p olarized excitation. An exponential growth of k = 0 LP emission has been ac hieved at high excitation densities for the major spin population leading t o the emission polarization degree higher than that of the excitation. The effect indicates the scattering stimulation appearing due to the bosonic na ture of polaritons when the high filling of k = 0 LP states is reached.