Polariton-induced optical asymmetry in semiconductor microcavities

Polariton-induced optical asymmetry in the reflectivity spectra of coupled semiconductor microcavity structures, containing quantum wells in one of the cavities, is reported. The central mode of the system is only observable when viewed from one side of the structure, but is dark and invisible from the other side. At the same time, all other spectral features are the same from both sides of the structure. Microscopically, interference between the exciton and cavity modes is shown to lead to the optical asymmetry. Furthermore, the asymmetric exciton-cavity mode is observable only for light incident on the cavity without excitons, a result shown to be fully consistent with a coupled oscillator model.