LAUSR

We study photon blockade effect in a loop-coupled double-cavity optomechanical system consisting of two cavity modes and one mechanical mode. Here, the mechanical mode is optomechanically coupled to the two cavity modes, which are coupled with each other via a photon-hopping interaction. By treating the photon-hopping interaction as a perturbation, we obtain the analytical results of the eigenvalues and eigenstates of the system in the subspaces associated with zero, one, and two photons. We find a phenomenon of optical normal-mode induced phonon-sideband splitting in the photon blockade effect by numerically calculating the second-order correlation function of the cavity fields. This work not only presents a method to choose optimal driving frequency of photon blockade by tuning the photon-hopping interaction, but also provides a means to characterize the normal-mode splitting with quantum statistics of cavity photons.