Phonon blockade via atomic coherence in a hybrid optomechanical system

A hybrid optomechanical system incorporating a two-level atom is utilized to realize phonon blockade, with the large-detuned optical mode decoupled from the system via adiabatic approximation. This process establishes an exchange interaction between the two-level atom and the mechanical mode. The findings indicate that both conventional and unconventional phonon blockade mechanisms coexist within the system. By tuning the driving frequency of the two-level atom, the system can be dynamically switched between these two mechanisms. The phonon blockade effect exhibits remarkable robustness against optical dissipation due to the adiabatic elimination of the cavity mode, enabling its realization even in low-Q cavities. In this study, the two-level atom serves not only as a critical component for achieving phonon blockade but also as an additional tool for manipulating the blockade mechanism. Our results provide a promising framework for hybrid optomechanical systems aiming to achieve switchable and robust single-phonon sources.