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

TL;DR

This paper proposes a method to achieve strong photon blockade using EIT with a single atom in a cavity, exploiting Stark shifts and dark-state polaritons to produce high-quality single photon sources.

Contribution

It introduces a novel approach combining Stark shift and EIT to enhance photon blockade, distinct from Kerr-based methods, enabling high transmission and strong antibunching.

Findings

Achieves photon antibunching with g^{(2)}(0) ~ 10^{-4}

Demonstrates immunity to spontaneous emission effects

Provides a new strategy for high-quality single photon sources

Abstract

We present an experimental proposal to achieve a strong photon blockade by employing electromagnetically induced transparency (EIT) with single alkaline-earth-metal atom trapped in an optical cavity. In the presence of optical Stark shift, both 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 Stark shift and control field, the strong photon blockade at atomic quasi-dark state resonance has an optimal second-order correlation function $g^{(2)}(0)\sim10^{-4}$ 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.