Optical bistability and cooling of a mechanical oscillator induced by radiation pressure in a hybrid optomechanical system

Abstract: We investigate theoretically the effect of optical feedback from a cavity containing an ultracold two level atomic ensemble, on the bistable behavior shown by mean intracavity optical field and the ground state cooling effect of the mechanical oscillator in an optomechanical cavity resonator. The optical bistability can be controlled by tuning the frequency and power of the single driving laser as well as by varying the atom-cavity coupling strength in the atomic cavity. Study of the cooling of the mechanical oscillator, in both good and bad cavity limits, reveals that the hybrid system is more efficient in cooling in comparison to a generic optomechanical setup, even at room temperature. In essence, our work emphasizes the impact of the coupling with the atomic cavity on the radiation pressure effects in the optomechanical cavity.