Unconventional photon blockade in cavity optomechanical system

Abstract

Traditionally, photon blockades (PB) are classified into two distinct categories—conventional and unconventional—based on their unique physical mechanisms. In relation to the cavity decay rate κ, conventional photon blockade occurs under conditions of strong nonlinearity (J>κ), while unconventional photon blockade is observed in situations of weak nonlinearity (J<κ). In this study, we examine a two-mode cavity optomechanical system (Jâ†â†b+Jââb̂†) and a two-photon parametric drive εp(â†â†+ââ). When the detunings significantly exceed the dissipation rates of the cavity (|Δa|,|Δb|≫κ), the optimal condition for PB becomes independent of the coupling strength. This implies that photon antibunching effects can occur in both strong and weak regimes (J>κ and J<κ), even when J∼κ, and we could achieve PB solely through the adjustment of detunings. Furthermore, we generalize the approach to the conversion between single photon and three photons (Jâ†3b+Jâ3b̂†) with a three-photon parametric drive εp(â†3+â3) and arrive at nearly identical conclusions. This work presents a method for implementing a single-photon source, which holds significant potential for practical engineering applications due to its independence from coupling strength.