Ground-State Cooling of the Mechanical Resonator in an Optomechanical Cavity with Two-Level Atomic Ensemble

We first propose the ground-state cooling of a mechanical resonator (MR) via a electromagnetically-induced-transparency (EIT)-like cooling mechanism in an optomechanical cavity with two-level atomic ensemble. By tuning optimal parameters in stable region, we meet that the cooling process of the MR corresponds to the maximum value of the optical fluctuation spectrum, while the heating process of the MR corresponds to the minimum value of the optical fluctuation spectrum. Without the original resolved sideband condition, the MR could be cooled to its ground state by manipulating the atom-field coupling strength only satisfying the decay rate is smaller than the MR’s frequency, which can be observed by the cooling rate and the mean phonon number. Meanwhile, the action of the atomic ensemble in the ground-state cooling of the MR is equal to the one of the auxiliary cavity in a double-cavity optomechanical system. In addition, the influence of other parameters on the cooling of the MR is also discussed. In the experiment and theory, the optomechanical cavity with two-level atomic ensemble is easier to implement and manipulate than the related double-cavity optomechanical system.