Abstract

It is generally understood that the effects of the Pauli excursion principle dominate the nonlinear optical response near the band edge in GaAs/ AlGaAs multiple-quantum-well (MQW) structures. The reduction of the excitonic oscillator strength from the exclusion principle has lead to observations of hole burning (increased transmission) in differential-transmission (DT) measurements of localized excitons.¹ Increased exciton absorption is also observed in this type of measurement in the high-excitation regime and is attributed to exciton energy shifts or exciton-exciton scattering. In this paper, we report observations of increased exciton absorption in the low-excitation regime in GaAs QW structures. Comparisons of differential transmission spectra with high-resolution four-wave-mixing (FWM) measurements suggest the increased absorption results from a long-range interaction.

© 1991 Optical Society of America