Abstract

In a quantum well (QW) free of imperfection, excitons can be characterized by an in-plane wave vector k_║ that couples only to photons with 3D wave vector k = (k_||, k_z). Consequently, for an incident light beam with k_||,, only beams in the specular direction and the incident direction are present. In real QWs, however, incident light near the exciton absorption peak is scattered in all directions because of spatial inhomogeneities in the QW^1,2 that break in-plane translational invariance. In recent experiments on the time- resolved flourescence of excitons under resonant picosecond excitation, or resonant Rayleigh scattering (RRS),³ Wang et al. have observed in the time domain the reflected scattered light from a resonantly excited QW off the specular direction.⁴ The scattered signal was found to exhibit a rise time of ~2 ps followed by nonex-ponential decay with a 10 ps component followed by 100 ps component.

© 1996 Optical Society of America