Coherent response of a semiconductor microcavity

The coherent dynamics of a semiconductor microcavity in the strong coupling regime has been studied by means of interferometric correlation measuremen ts with subpicosecond time resolution in a backscattering geometry. We show that, in this geometry, all the experimental coherent response of the micr ocavity, even the unexpected stationary coherence observed for the lower po lariton branch close to resonance, can be reproduced assuming a coherent su perposition of the reflectivity and resonant Rayleigh scattering signals wi th a well defined relative phase.