  The correlation function of radiation from a high-quality semiconductor
microcavity at the resonant laser excitation demonstrates oscillations with
surprisingly long-period and damping times of a nanosecond range. It was shown
that the oscillations are not attributed to weak Rabi interaction between
long-lived exciton states and intracavity electromagnetic field. The study of a
response with high spectral resolution had revealed that the oscillations arise
if a spectral position as well as a period of longitudinal laser modes is
similar to modulation components of a microcavity transmission spectrum.
