Strong photon antibunching effect in a double-cavity optomechanical system with intracavity squeezed light

We study the behaviour of the second-order correlation function in a double-cavity optomechanical system, and a degenerate optical parametric amplifier is placed in each cavity. The first cavity is additionally driven by a weak classical laser field. The occurrence of strong photon antibunching effect in these two coupled cavities is observed. For suitable values of optomechanical coupling strength as well as photon hopping process, the system can exhibit a very strong photon antibunching effect. Our study also shows that the unconventional photon blockade occurs in both coupling, i.e. the weak coupling and the strong coupling regimes as compared to the conventional photon blockade which occurs only in the strong coupling regime. We get a very strong photon antibunching effect under the unconventional photon blockade mechanism than the conventional photon blockade mechanism. Our study can be also used for the generation of single photon in coupled nonlinear optomechanical systems.