Coherent dynamics of microcavity polaritons in the nonlinear regime

We report an experimental study of polariton coherent dynamics in II–VI semiconductor microcavities in the nonperturbative regime, using transient four-wave mixing. By comparison with model calculations based on the resolution of Bloch–Maxwell equations, we show that Pauli blocking and Coulomb interactions induce different coherent dynamics. We deduce a method to determine experimentally the nature of intrinsic nonlinearities in semiconductor microcavities. In particular, we show that upper and lower polariton modes experience distinct nonlinear dynamics.