The role of the atom-cavity detuning in bimodal cavity experiments

The coherent evolution of the atom-cavity state in bimodal (cavity) experiments has been analyzed for a realistic time-dependence in detuning the atomic transition frequency. Apart from a `smooth switch' of the atomic resonance from one to the second mode of a bimodal cavity, we considered also an additional (effective) interaction between the field modes of the cavity, known as `communication channel'. Comparison of our model computations has been made especially with the measurements by Rauschenbeutel et al., [2001 Phys. Rev. A 64 050301] who demonstrated for the first time the entanglement of the field modes in a bimodal cavity. It is shown that the agreement between the (theoretically) predicted and experimental phase shifts can be improved by allowing a `communication' between the two field modes during a short but finite switch of the atomic transition frequency from one mode to the other. We therefore suggest that the details of the atom-cavity detuning should be taken into account for the future interpretation of bimodal cavity experiments.