Strongly enhanced photon-pair blockade with three-wave mixing by quantum interference

In this paper, the photon-pair blockade effect in a three-wave mixing system with Kerr nonlinearity has been studied. By analytical calculation and numerical analysis, we find that the conventional photon blockade and unconventional photon blockade of the photon pair could be realized simultaneously in the strong-coupling regime in this system, and the photon-pair blockade effect could be enhanced strongly by the combination of them. The combination could also lead to a much stronger photon-pair blockade effect in this hybrid system than in a three-wave mixing system, which may contribute to construction of single photon-pair sources with much higher purity without the loss of brightness. In addition, both the same-frequency and different-frequency photon-pair blockades could be realized in this scheme, which may contribute to construction of the same-frequency or different-frequency photon-pair sources or devices. All the results may provide useful theoretical references for the design of correlated photon-pair sources or devices in future experiments and applications.