A Compact Source for Quantum Image Processing with Four-wave Mixing in Rubidium-85

TL;DR

This paper presents a compact, efficient source of bright squeezed twin-beams at 795 nm using four-wave mixing in rubidium-85 vapor, with potential applications in quantum calibration and atom-light interactions.

Contribution

The work demonstrates a compact, high-power four-wave mixing source producing 2.1 dB squeezing at 795 nm, and explores its dispersion properties for quantum information applications.

Findings

Achieved 2.1 dB intensity difference squeezing below the standard quantum limit.

Generated bright twin-beams suitable for quantum calibration and atom-light interaction studies.

Investigated dispersion effects related to the four-wave mixing process.

Abstract

We have built a compact light source for bright squeezed twin-beams at 795\,nm based on four-wave-mixing in atomic $^{85}$Rb vapor. With a total optical power of 400\,mW derived from a free running diode laser and a tapered amplifier to pump the four-wave-mixing process, we achieve 2.1\,dB intensity difference squeezing of the twin beams below the standard quantum limit, without accounting for losses. Squeezed twin beams generated by the type of source presented here could be used as reference for the precise calibration of photodetectors. Transferring the quantum correlations from the light to atoms in order to generate correlated atom beams is another interesting prospect. In this work we investigate the dispersion that is generated by the employed four-wave-mixing process with respect to bandwidth and dependence on probe detuning. We are currently using this squeezed light source to test the transfer of spatial information and quantum correlations through media of anomalous dispersion.