Photon blockade with high photon occupation via cavity electromagnetically induced transparency.

Photon blockade (PB) is one of the effective methods to generate single-photon sources. In general, both the PB effect with the significant sub-Poissonian statistics and a large mean photon number are desired to guarantee the brightness and the purity of single-photon sources. Here, we propose to obtain the PB effect at the cavity dark-state polariton (DSP) using a cavity Λ-type electromagnetically induced transparency (EIT) system with and without the two-photon dissipation (TPD). In the Raman resonance case, the PB effect at the DSP could by realized by using the TPD process in the weak or intermediate coupling regime, which accompanies with near unity transmission, i.e., very high photon occupation. In the slightly detuned Raman resonance case, the excited state is induced into the components of the DSP, and the atomic dissipation path is added into the two-photon excitation paths. Thus, the PB effect at the DSP can be obtained due to the quantum destructive interference (QDI) in the strong coupling regime, which can be further enhanced using the TPD process. Due to the slight detuning, the PB effect still remains high photon occupation and has highly tunability. This work provides an alternative way to manipulate the photon statistics by the PB effect and has potential applications in generating single-photon sources with high brightness and purity.