Physical Review A
Steady-state solutions of a hybrid system involving atom-light and optomechanical interactions: Beyond the weak-cavity-field approximation
Chang-Bao Fu, Xiao-Bo Yan, Kai-Hui Gu, Cui-Li Cui, Jin‐Hui Wu, Tai-Dong Fu
Abstract
We investigate the steady-state properties of a hybrid system where many cold atoms are confined in an optical cavity with a movable end mirror. The confined cold atoms interact with an external pump field and an internal cavity field in the three-level $\ensuremath{\Lambda}$ configuration. The internal cavity field is excited by an external driving field and exerts a radiation pressure upon the movable end mirror. Then the coupled atom-light and optomechanical interactions offer an efficient nonlinear feedback mechanism permitting the observation of three steady-state solutions for relevant variables near one atomic resonance. We find, in particular, that the weak-cavity-field assumption may result in very large errors for the first and second solutions when the number of cavity photons is only about ${10}^{6}$. The main reason is that a typically weak light field can result in a sufficiently strong atom-light interaction in a very small cavity. Going beyond the weak-cavity-field assumption also allows us to observe an otherwise absent bistable behavior for the first solution in terms of mirror displacement and cavity photons, which is easy to control by modulating the pump and driving fields.