Influence of exciton-exciton interaction on quantum beats

Summary form only given. As we have shown recently, measurement of the polarization-sensitive phase of the quantum beats in time-integrated four wave mixing (FWM) signal provides us with a novel and effective tool here. The amplitude and phase of the oscillating TI-FWM signal are determined by the interplay of the four-particle correlation and mean field mechanisms of the optical nonlinearity at the fundamental band edge. We report on our recent results on the study of the quantum beats between excitons in GaN and ZnSe and also beats between cavity polaritons in AlAs-GaAs QW embedded into the high-Q microcavity. By measuring the phase of the quantum beats from A- and B-excitons exciting with circular polarized light, we find that exciton-exciton interaction plays a major role in the phase shift of the beats in GaN and ZnSe. Together with the beating phase measurements in high-Q semiconductor microcavity for various polarization configurations, our experiments reveal an important role of the exciton-exciton interaction for the transient nonlinear response in /spl chi//sup (3)/-regime.