Theory of nonlinear optical absorption in coupled-band quantum wells with many-body effects

Abstract
Nonlinear optical absorption spectra and refractive index changes are computed for coupled-band semiconductor quantum wells by numerically solving the interband polarization equation. The theory combines band-structure engineering with many-body techniques and is applied to lattice-matched GaAs-AlGaAs and strained InGaAs-GaAs systems with carrier densities ranging from the excitonic to the gain regimes. Good agreement with recent experimental results is found.