Abstract

We have performed linear spectral reflection and transmission measurements on (Bragg) λ_exciton/2 spaced In₀₄Ga₉₆As quantum wells (QWs) and modeled our results with the linear dispersion model. In multiple-QW structures, the transverse optical field couples exciton states in different QWs, which leads to a collective optical response of the system. It has been predicted that for Bragg QW structures, the radiative coupling causes a stimulated decay of the excitons, which can be seen temporally or spectrally. Temporally, the signature of the collective response is a fast radiative decay of the excitons (superradiance). This has been observed experimentally by Hübner et al.¹ The spectral equivalent is a broadening in the reflectivity R, transmittance T, and absorption A = 1 – R – T.^2,3

© 1998 Optical Society of America