Realization of a twin beam source based on four-wave mixing in Cesium

TL;DR

This paper reports the first realization of a four-wave mixing twin beam source using cesium vapor, leveraging atomic resonance to generate intense, non-classical twin beams suitable for quantum applications.

Contribution

It introduces the first experimental implementation of a cesium-based four-wave mixing source for twin beams near atomic resonance.

Findings

Successful generation of twin beams via 4WM in cesium vapor

Twin beams have frequencies close to atomic transitions

The source produces intense, non-classical twin beams

Abstract

Four-wave mixing (4WM) is a known source of intense non-classical twin beams. It can be generated when an intense laser beam (the pump) and a weak laser beam (the seed) overlap in a $\chi^{(3)}$ medium (here cesium vapor), with frequencies close to resonance with atomic transitions. The twin beams generated by 4WM have frequencies naturally close to atomic transitions, and can be intense (gain $\gg 1$) even in the CW pump regime, which is not the case for PDC $\chi^{(2)}$ phenomenon in non-linear crystals. So, 4WM is well suited for atom-light interaction and atom-based quantum protocols. Here we present the first realization of a source of 4-wave mixing exploiting $D_2$ line of Cesium atoms.