Phase space filling contribution to the polariton nonlinear dynamics in the nonperturbative regime

Summary form only given. We present an experimental study of polariton coherent dynamics in II-VI semiconductor microcavities, in the non-perturbative regime. Due to their excitonic component, polaritons are composite bosons that can interact via Coulomb interactions (CI) as well as phase space filling (PSF). Several authors have reported experimental findings on polariton nonlinear dynamics that have been assigned to their bosonic properties (stimulated relaxation, parametric amplification). In this context, an experimental determination of the nature of the intrinsic nonlinearities for given excitation conditions is clearly desirable. We have recently developed an experimental method to determine the ratio between PSF and CI using four-wave mixing that we apply to the study of the low-energy polariton for various exciton-to-photon detuning.