Degenerate Four-Wave Mixing In Semiconductors: Application To Phase Conjugation And To Picosecond-Resolved Studies Of Transient Carrier Dynamics

Semiconductors appear to have excellent potential as materials for phase conjugation via degenerate four-wave mixing (DFWM) because of the large variety of nonlinear optical mechanisms that may be invoked in them. When the optical wavelength is near or above the band gap, mobile particles such as free electrons and holes or free excitons may be created; in such cases, DFWM itself provides a powerful contact-free and nondestructive technique for the study of carrier transport and decay parameters, such as ambipolar diffusion coefficients and recombination times. In this article, we briefly review the various nonlinear mechanisms that may be used for DFWM, as well as the various DFWM and related "transient grating" experiments that have been performed for application to phase conjugation and to carrier dynamics studies.