Antibunched photon-pair source based on photon blockade in a nondegenerate optical parametric oscillator

Nonclassical light sources, such as correlated photon pairs, play an important role in quantum optics and quantum information processing systems. This study proposes a process to generate antibunched photon pairs in a nondegenerate optical parametric oscillator. It is found that when the parameters of the system satisfy certain conditions, the generated photons in subharmonic modes exhibit a strong antibunching behavior and are strongly correlated with one another. In particular, the average photon-pair number is resonantly enhanced. It is also observed that the conventional photon blockade contributes to this phenomenon. In addition, it is interesting to note that fundamental mode photons can blockade the subharmonic mode photons. We refer to this phenomenon as a heterogeneous photon blockade.