Controllable optical bistability in an optomechanical ring cavity with an atomic ensemble and the Coulomb interaction

The optical bistable characteristics of an optomechanical ring cavity containing a two-level atomic ensemble and Coulomb interaction between a cavity mirror and an external nanoresonator are theoretically investigated. Dynamics of the hybrid systems is actuated by Heisenberg–Langevin equations of motion. We derive the mean photon number equation and study the steady-state solution behavior. The optomechanical ring cavity exhibits the optical bistability by selecting appropriate parameters. In addition, we investigate the effect of parameters on optical bistability. The optical bistability threshold and the width of the optical bistability curve can be controlled by adjusting the vibration frequencies of the movable mirrors, the two-level atomic ensemble coupling strength, Coulomb interaction coupling strength between a cavity mirror and an external nanoresonator and the cavity decay rate.