Abstract

We performed a systematic study of the changes in the excitonic properties of GaAs multiple-quantum-well structures induced by a femtosecond laser pulse falling in the transparency region of the material, below the lowest heavy-hole exciton. Such nonlinear effects are of great importance for applications in ultrafast all-optical devices, since they have an inherent very fast response time and low-power dissipation, being associated with virtual interband transitions. Experiments have been performed as a function of laser detuning from the lowest exciton resonance (at fixed laser intensity) or alternatively as a function of input laser intensity at a fixed detuning. Furthermore, results obtained in several samples with different well and barrier sizes have been compared using similar excitation conditions.

© 1987 Optical Society of America