Pulse propagation and many-body effects in semiconductor four-wave mixing

Abstract

The semiconductor Maxwell-Bloch equations are solved to study the simultaneous influence of pulse propagation effects and Coulomb many-body interaction on the four-wave-mixing signal of semiconductors. Temporal and spatial modulations as well as the decay of time-resolved and time-integrated signals are analyzed for various excitation conditions. It is shown that propagation effects may significantly modify the line shapes depending on sample thickness and excitation conditions. In most cases the signal is more influenced by its own propagation than by the propagation of the input pulses. Exciton-polariton effects are recovered in the low intensity limit. For relatively thin samples an increased temporal decay is observed whereas for thicker samples the propagation effects lead to strong beats in real time. For higher intensities, where an echolike structure is generated, the competition of signal generation by the pump pulses and absorption by the semiconductor determines the output.