Polariton effects on first-order Raman scattering in II-VI microcavities

The polariton modes of a II-VI semiconductor quantum-well-embedded planar microcavity are studied by resonant Raman scattering as a function of cavity-exciton detuning. A maximum in the Raman efficiency is observed at the mode anticrossing, with minima in the pure photon and exciton limits. The results are compared with an optically nonconfined structure and discussed within the framework of existing theories of polariton-mediated Raman scattering, adapted to optically confined structures. It is shown that polariton effects are apparent in planar microcavities due to k_z quantization and a peculiar polariton density-of-states cancellation in the scattering efficiency. The detuning dependence of the Raman efficiency reflects the varying photon and exciton strengths of the coupled-mode wave function, unambiguously revealing the involvement of cavity polaritons as intermediary states in the scattering process.