We present an experimental proposal to achieve a strong photon blockade by employing electromagnetically induced transparency (EIT) with a single alkaline-earth-metal atom trapped in an optical cavity. In the presence of optical Stark shift, both the second-order correlation function and cavity transmission exhibit asymmetric structures between the red and blue sidebands of the cavity. For a weak control field, the photon quantum statistics for the coherent transparency window (i.e., atomic quasi-dark-state resonance) are insensitive to the Stark shift, which should also be immune to the spontaneous emission of the excited state by taking advantage of the intrinsic dark-state polariton of EIT. Interestingly, by exploiting the interplay between the Stark shift and control field, the strong photon blockade at atomic quasi-dark-state resonance has an optimal second-order correlation function $g^{(2)}(0)\sim {10}^{-4}$ and a high cavity transmission simultaneously. The underlying physical mechanism is ascribed to the Stark shift enhanced spectrum anharmonicity and the EIT hosted strong nonlinearity with loss-insensitive atomic quasi-dark-state resonance, which is essentially different from the conventional proposal with emerging Kerr nonlinearity in cavity-EIT. Our results reveal a new strategy to realize high-quality single photon sources, which could open up a new avenue for engineering nonclassical quantum states in cavity quantum electrodynamics.

中文翻译：

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电磁感应透明下腔中单个原子的可调谐光子阻挡

我们提出了一个实验建议，通过使用电磁感应透明 (EIT) 和一个被困在光学腔中的碱土金属原子来实现强光子阻挡。在存在光学斯塔克位移的情况下，二阶相关函数和腔传输都在腔的红蓝边带之间表现出不对称结构。对于弱控制场，相干透明窗口的光子量子统计（即原子准暗态共振）对斯塔克位移不敏感，利用EIT 的固有暗态极化子。有趣的是，通过利用斯塔克位移和控制场之间的相互作用，$G^{(2)}(0)～{10}^{-4}$和高腔传输同时。潜在的物理机制归因于斯塔克位移增强的光谱非谐性，并且 EIT 具有强非线性，具有对损耗不敏感的原子准暗态共振，这与空腔 EIT 中出现的克尔非线性的传统方案有本质的不同。我们的研究结果揭示了一种实现高质量单光子源的新策略，这可以为腔量子电动力学中的非经典量子态工程开辟一条新途径。