Coherent emission pattern of a semiconductor microcavity

We present a detailed study of the angular pattern of the coherent emission from a semiconductor microcavity, under normal incidence excitation. Exper imental results obtained by means of interferometric correlation measuremen ts with subpicosecond resolution and by means of frequency and angle resolv ed cw spectra are compared. We show that a clear distinction between reflec tivity and resonant Rayleigh scattering can be very difficult, as interfere nce effects between the two coherent emissions play an important role. The frequency spectra of several RRS speckles have been measured for both the u pper and lower polariton branches, denoting a long coherence time and a rel evant role played by the microcavity wedge.