Abstract

We present a many-body analysis of optical nonlinearities in type-I and type-II quantum wells and compare the results to nanosecond and femtosecond measurements on GaAs/Al_xGa_1−x.As samples. In our theory we numerically solve the equations for the interband polarization for light-hole (LH) and heavy-hole (HH) transitions, including the relevant exchange and dynamic screening effects.^1-3 For the type-II structures we assume perfect electron-hole charge separation, so only the Γ-point holes contribute to phase-space filling of the GaAs exciton states. Inhomogeneous broadening resulting from well-width fluctuations is included by averaging the spectra over a distribution of well thicknesses assuming approximate half-monolayer-thickness fluctuations.

© 1991 Optical Society of America