Off-resonance behavior of atomic interaction with cavity fields of arbitrary detunings

The Jaynes-Cummings (JC) model has been studied extensively because of its simple and realistic representation of the dipole interaction between an atom and the quantized radiation field. It exhibits, without perturbative expansions or statistical decorrelations, many quantum mechanical effects in the case of strong or weak interaction, long or short time regime, on or off the resonance. The model is extended to a three-level atom for the investigation of physical phenomena associated with two-photon processes.