Generation of higher-order atomic dipole squeezing in a high-Q micromaser cavity. (IV) Discussion of the nondegenerate two-photon Jaynes–Cummings model

The concept of higher-order atomic dipole squeezing (HOADS) was introduced in our previous paper (Physica A 246 (1997) 529) and developed in our recent works. In this paper, we consider the case of a two-level atom interacting with two-mode coherent fields in a high-Q micromaser cavity, i.e., a nondegenerate two-photon Jaynes–Cummings model (NTPJCM). Assuming that the radiation fields are initially in an uncorrelated coherent state, we investigate HOADS in the NTPJCM, including the discussion of the effects of the detuning and the phase difference between the uncorrelated coherent fields on HOADS. It is found that the higher-order quantum fluctuations in the absorptive part of the atomic dipole may go below the standard limit for the on- and off-resonance excitations if the phase difference between the uncorrelated coherent fields is adjusted properly. Especially, it shows a greater amount of squeezing in the resonant case. The relation between HOADS and second-order ADS is discussed.