ASYMMETRIC QUANTUM-WELL OPTICS FROM A MEAN-FIELD POLARITON THEORY

We cosider the elementary excitations in quantum wells of arbitrary shape, as they result from the coupling between excitons and electromagnetic radiation. The exciton states are obtained from a two-band model [1]. The solutions of Maxwell equations with the appropriate exciton dependent nonlocal susceptibility are obtained by using a mean field approach [2] based on the fact that the radiation wavelength lambda is much larger than the well width L. Application to asymmetric wells gives the polariton dispersion modes and the radiative linewidths for all possible well shapes. The splitting of the Z-mode and the values of the radiative lifetimes strongly depend on the well width L and its asymmetry. The reflectivity and absorption are computed and are shown to give strong evidence of polariton modes.