Abstract
We show by means of time-resolved four-wave-mixing experiments that the simultaneous excitation of energetically distinct and inhomogeneously broadened exciton transitions associated with spatially separated quantum-well islands leads to a beating photon echo. This shows that the exciton transitions cannot be described by uncoupled two-level systems. We discuss bleaching, screening, and dipole-dipole interaction as possible coupling mechanisms.
- Received 24 June 1993
DOI:https://doi.org/10.1103/PhysRevB.48.11480
©1993 American Physical Society
