Comparison of optical nonlinearities of type II and type I quantum wells

摘要

We have performed lowhyphen;temperature femtosecond pump and probe experiments on GaAs/AlAs type II and GaAs/AlGaAs type I multiple quantum wells of similar well sizes. The measurements are analyzed using a manyhyphen;body theory appropriate for both types of systems. It is found that the type I and type II nonlinearities are very similar at early times after excitation. However, the very fast (1 ps) Ggr; toXelectron scattering in the type II samples causes pronounced differences at later times, allowing the observation of hole relaxation in the type II samples.