Implementation of Composite Photon Blockade Based on Four-wave Mixing System

Abstract: A high-quality single-photon blockade system can effectively enhance the quality of single-photon sources. Conventional photon blockade(CPB) suffers from low single-photon purity and high requirements for system nonlinearity, while unconventional photon blockade(UPB) has the disadvantage of low brightness. Recent research by [Laser Photon.Rev 14,1900279,2020] demonstrates that UPB can be used to enhance the strength of CPB, thereby improving the purity of single-photon sources. Research by [Opt. Express 30(12),21787,2022] shows that there is an intersection point between CPB and UPB in certain nonlinear systems, where the performance of single photons is better. In this study, we investigated the phenomenon of photon blockade in a non-degenerate four-wave mixing system, where CPB and UPB can occur simultaneously within the same parameter range. We refer to this phenomenon as composite photon blockade. Particularly, when the system achieves composite photon blockade, the value of g(2)(0) is smaller, and there are more single photons. We conducted analytical analysis and numerical calculations to study the conditions for the realization of CPB, UPB, and 2PB in the system, and discussed in detail the influence of system parameters on various blockade effects.