Microcavity polariton scattering probed by coherent control experiments

We present coherent control experiments which simultaneously probe both the coherence and the population dynamics of the exciton-photon polariton stat es in a semiconductor microcavity. The coherent manipulation of either the spin orientation or the density of polaritons is demonstrated leading to th e measurement of the optical dephasing time. The polariton scattering by ac oustical phonons or by mutual collision processes are investigated by a sim ultaneous measurement of both the optical dephasing time T-2 and the decay time T-1 of the radiant states. These results clearly evidence a quenching of the different scattering processes at resonance. (C) 1999 Academic Press .