Tunable photon blockade with a single atom in a cavity under electromagnetically induced transparency

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)similar to 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. (C) 2021 Chinese Laser Press

Automated summary

An experimental proposal is presented to achieve strong photon blockade using electromagnetically induced transparency (EIT) with a single alkaline-earth-metal atom trapped in an optical cavity. By exploiting the interplay between the Stark shift and control field, the system achieves optimal second-order correlation function and high cavity transmission at the atomic quasi-dark-state resonance. This new strategy opens up avenues for engineering nonclassical quantum states in cavity quantum electrodynamics.