Abstract

The high-intensity excitation of electronhole pairs in the vicinity of the band gap in GaAs saturates the corresponding optical transition and thus gives rise to an optical nonlinearity. Optical nonlinear interactions with this plasma carry information on the relaxation dynamics of the electron-hole pairs. Time-resolved pump and probe experiments permit us to study the evolution of the quasi-equilibrium hot-carrier distribution. In the four-wave mixing configuration, varying the relative polarizations of the input beams allows us to separate the contributions of concentration and orientational gratings.¹

© 1984 Optical Society of America