Abstract

The ultrafast dynamics of nonlinear optical polarizations resonant to the bandgap of semiconductors is governed by nonequilibrium properties of photoexcited carriers. Transient coherent spectroscopy with femtosecond laser pulses gives direct insight into these phenomena. In this paper, we present spectrally and temporally resolved four-wave-mixing (FWM) studies of bulk GaAs, providing new information on the nonlinear polarization of direct-gap semiconductors. The experimental results are analyzed by theoretical calculations based on the optical Bloch equations for the FWM geometry including Monte Carlo simulations of the carrier dynamics.

© 1994 Optical Society of America