Superradiant cascade emissions in an atomic ensemble via four-wave mixing

TL;DR

This paper explores superradiant cascade photon emissions in atomic ensembles driven by four-wave mixing, focusing on the cooperative Lamb shift and its potential for quantum network applications.

Contribution

It introduces a method to generate superradiant photon pairs via four-wave mixing and analyzes the cooperative Lamb shift in cylindrical atomic ensembles, highlighting its observability and quantum information relevance.

Findings

Superradiant photon pairs can be generated through four-wave mixing in atomic ensembles.

The cooperative Lamb shift of the idler photon depends on the ensemble geometry.

Maximum observable CLS can be significant for quantum network applications.

Abstract

We investigate superradiant cascade emissions from an atomic ensemble driven by two-color classical fields. The correlated pair of photons (signal and idler) is generated by adiabatically driving the system with large-detuned light fields via four-wave mixing. The signal photon from the upper transition of the diamond-type atomic levels is followed by the idler one which can be superradiant due to light-induced dipole-dipole interactions. We then calculate the cooperative Lamb shift (CLS) of the idler photon, which is a cumulative effect of interaction energy.We study its dependence on a cylindrical geometry, a conventional setup in cold atom experiments, and estimate the maximum CLS which can be significant and observable. Manipulating the CLS of cascade emissions enables frequency qubits that provide alternative robust elements in quantum network.