Squeezed Light and Entangled Images from Four-Wave-Mixing in Hot Rubidium Vapor

TL;DR

This paper demonstrates the generation of quantum-entangled images using nondegenerate four-wave mixing in hot rubidium vapor, achieving multi-spatial-mode entanglement without an optical cavity, with potential applications in quantum information.

Contribution

It introduces a cavity-free four-wave mixing scheme in rubidium vapor that produces multi-spatial-mode entangled fields verified by squeezing measurements.

Findings

Over 4 dB of squeezing in amplitude difference noise

Generation of inherently multi-spatial-mode entangled fields

Analysis of quantum properties of four-wave-mixing amplifiers

Abstract

Entangled multi-spatial-mode fields have interesting applications in quantum information, such as parallel quantum information protocols, quantum computing, and quantum imaging. We study the use of a nondegenerate four-wave mixing process in rubidium vapor at 795 nm to demonstrate generation of quantum-entangled images. Owing to the lack of an optical resonator cavity, the four-wave mixing scheme generates inherently multi-spatial-mode output fields. We have verified the presence of entanglement between the multi-mode beams by analyzing the amplitude difference and the phase sum noise using a dual homodyne detection scheme, measuring more than 4 dB of squeezing in both cases. This paper will discuss the quantum properties of amplifiers based on four-wave-mixing, along with the multi mode properties of such devices.