Effects of Electronic Fourth-Order Correlations on the Pump-Probe Response of Semiconductors

Abstract

The pump-and-probe response of a ZnSe quantum well is investigated. In this particular sample the binding energy far exceeds both the exciton damping and the inhomogeneous broadening. A comparison between experimental data and model calculations shows that with co-circularly polarized beams the nonlinear mean-field contributions dominate those induced by four-particle correlations. In contrast, only the four-particle correlations contribute to the signal in counter-circular configuration. For this configuration, the exciton–biexciton interaction dominates the response for resonant excitation of the exciton. The occurrence of exciton–biexciton transitions leads to a renormalization of the period of coherent oscillations at negative pulse delay.