Abstract

Type I quantum-well structures are promising candidates as active devices in fast optoelectronics. Because of the forced confinement of electrons and holes in the same layer, pronounced excitonic structures are observed up to room temperature, even in materials with small bulk exciton binding energy. Optically induced changes of such excitonic structures lead to the large and very rapid nonlinearities required in device applications. We describe here some of the underlying physical processes. The discussion is restricted to the case of GaAs quantum wells, with the accent put on those effects affecting the lowest (heavy-hole) exciton resonance on a picosecond or subpicosecond time-scale.

© 1987 Optical Society of America