Single-photon and two-photon blockade in a three-wave mixing system with a two-level atom

This paper discusses conventional photon blockade (CPB) and two-photon blockade (2PB) in a three-wave mixing system embedded with a two-level atom in the high-frequency cavity. Analytical conditions for achieving CPB and 2PB are obtained by analyzing the eigenvalues of the system Hamiltonian. Numerical solutions, derived by solving the master equation in a truncated Fock space, are consistent with the analytical conditions. Detailed analysis of system parameters reveals the influence of the embedded atom on achieving different types of photon blockade. Unlike previous schemes, this system can achieve single-photon blockade simultaneously in three photon modes. Additionally, by adjusting the coupling coefficient between the atom and high-frequency mode photons, the system can switch between single-photon blockade and two-photon blockade in the high-frequency mode.