PARAMETRIC SCATTERING OF CAVITY POLARITONS

We report frequency-domain degenerate four-wave mixing results on exci tons in a semiconductor microcavity in the strong coupling regime. The excitation is kept to the chi((3)) limit. The spectral response shows strong polarization dependence. We analyze the data with a new model where the degenerate four-wave mixing process is described as an elast ic scattering of two cavity polaritons mediated by the state filling e ffect and the two-body attractive and repulsive interaction between ex citons. From the polarization and detuning dependence, the ratio of th e coupling constants of these three terms is uniquely determined. We f ind that the attractive interaction term and the state filling are the dominant contributions to the nonlinearity.