THEORY OF QUASI-EQUILIBRIUM NONLINEAR-OPTICAL ABSORPTION IN SEMICONDUCTOR SUPERLATTICES

Quasiequilibrium nonlinear optical absorption spectra are computed for semiconductor superlattices. The theory generalizes the semiconductor Bloch equations to describe anisotropic structures. The equation for the interband polarization is solved numerically and the carrier-densi ty dependent optical nonlinearities are computed. Starting from excito nic absorption, with increasing density exciton saturation and the dev elopment of gain is observed. The dependence of the gain spectra on st ructural parameters of the superlattice is discussed. (C) 1995 America n Institute of Physics.