Linear Birefringence in GaAs/AlAs Multiple Quantum Wells

Transmission spectroscopy has been used to investigate the in-plane linear birefringence of GaAs/AlAs multiple quantum wells (MQWs) with symmetric wells/barriers from 20/20 to 70/70 A. Varying optical thicknesses of the samples have been used to measure a reference value of the birefringence. While the resonant part in the dispersion of the birefringence has been attributed to the contribution from the confined electronic gaps, a nonresonant background birefringence has been analyzed as a function of the MQW period and explained by the presence of local fields.