Photon Blockade in Cavity Optomechanics Via Parametric Amplification

Photon blockade is a quantum phenomenon in driven nonlinear systems. It can be observed in cavity optomechanical systems when nonlinear optomechanical interaction occurs at the single-photon level. However, achieving photon blockade in experiments is challenging due to the small single-photon optomechanical coupling strength. Here, photon blockade in an optomechanical system is investigated, where the cavity mode is either strongly or weakly squeezed. When the cavity mode is strongly squeezed, the coupling between squeezed mode and mechanical mode will be exponentially enhanced, leading to strong optical nonlinearity that is required for the realization of photon blockade. In contrast, when the cavity mode is weakly squeezed, the nonlinear optomechanical interaction is weak. It is shown that photon blockade can also be realized through the destructive interference of two paths for two-photon excitation. Interestingly, it is found that a larger mechanical decay rate facilitates the implementation of the interference-based photon blockade, and thermal noise effects can be significantly suppressed by the destructive interference.