Intensity auto- and cross correlations for a three-level Λ-type atom in a driven, damped two-mode cavity

We calculate intensity autocorrelations and cross correlations for the light transmitted from a system consisting of a three-level Lambda-type atom inside an optical cavity that supports two orthogonally polarized modes with one mode of the cavity weakly driven on resonance. We also include damping of the cavity modes and spontaneous emission from the atom using the framework of quantum trajectory theory. The correlation functions are compared with those of a two-level atom/cavity system as the coupling to the third level is increased, and we find a transition from photon bunching to photon antibunching. The three-level model allows the atom to couple to both field modes for which we calculate intensity cross correlations that exhibit nonclassical behaviors. Finally, we discuss the lack of entanglement between the field modes despite their common coupling to the same atom and the presence of atom-field entanglement. (C) 2012 Optical Society of America