Abstract

The excitonic nonlinear optical effects in semiconductors, such as phase-space tilling, exchange interaction, and Coulomb screening, manifest a distinctive spin dependence that has attracted considerable attention recently.¹ Recent work has shown that exciton-exciton interactions with different spin characteristics result in distinct effects on dephasing and line broadening and determine the basis for the nonlinear optical response.² Here, we report measurement of the red shift due to spin-dependent (SD) nonlinearities by using highresolution polarization-sensitive cw four-wave mixing (FWM) at low temperatures in GaAs.

© 1994 Optical Society of America