Transmission Analysis Of Cavity Field Interacting With Atomic Ensemble Based On The Non-Rotating-Wave Approximation

The dynamics of the interacting system of cavity and atom ensemble can be studied with J-C model based on the interaction between two-level atom and cavity. In an open interacting system of atom ensemble and cavity, the energy levels of both cavity and atom could be damped. A classical light is added in terms of observation and compensation to the damping. The radiation of this kind of field shows features such as couple coefficient dependent, frequency detuning between atom, field and the classical field, and the strength of the classical field.Generally, Rotate Wave Approximation(RWA) is adopted to study atom or atom ensemble interacting with cavity. The system’s dynamics can be accurately solved based on RWA. But ignoring the high frequency virtual processes should be under certain conditions, such as the interaction should be weak. This means that the so-called “virtual processes” that would cause high-order transitions should not be ignored, when it comes to any atom-cavity coupling.In this paper, we study the time-dependent evolution feature of the field mode in cavity, using the Hamiltonian of cavity interacting with two-level atom under no RWA. The cavity loss and atom ensemble loss in real condition are considered during the analysis, and a single-mode driven field is set to satisfy the measuring need. Meanwhile, analytical results of the time-dependent field operator and atom operator are calculated using Laplace transformation. Also, the photon radiation of containing one atom ensemble transition mode and two atom ensemble transition mode are analytical studied. The steady state of cavity mode’s damping and the relation between the time-dependent results and the interaction parameters or frequency detuning are studied as well. The results show that the steady state of the cavity mode is determined by the interaction between atom and cavity field, the frequency detuning among atom, cavity mode and the classical field, and the damping of both cavity mode and atom ensemble. When atom ensemble and cavity are both prepared in original state of the coherent state, the oscillation of cavity mode evolved with time is obvious. The oscillation is more obvious when the both of them are prepared in Fock state rather than one prepared in coherent state and the other prepared in Fock State. This has bonded with the feature of the coherent state itself.