Kinetics of excitons and polaritons in pure GaAs studied by optical spin orientation

Abstract

We have investigated the polarized exciton photoluminescence of high purity GaAs under circularly polarized excitation. The variation of the luminescence polarization with exciting intensity permits us to determine the formation coefficient of excitons γ ≈ 5 × 10-9 cm3 s-1. The non-uniform polarization of the polariton recombination lines at low and medium intensities show that the polariton population is not thermalized. In contrast, at high intensity, the polarization is uniform and thermalization is achieved.