Correlation measurements in cavity QED: detuning effects

Summary form only given. The second-order correlation function of the intensity is a measurement of the intensity fluctuations and their enhancement or suppression relative to an ideal laser field. It is a sensitive probe of the dynamic processes involved in producing the light. We have measured the correlation function of the photons escaping from a cavity QED system consisting of a high-finesse interferometer traversed by an atomic beam of optically pumped Rb atoms. We observe nonclassical correlations, exhibiting antibunching and sub-Poissonian statistics.