Improved measurement of two-mode quantum correlations using a phase-sensitive amplifier

TL;DR

This paper demonstrates that using a phase-sensitive amplifier to pre-amplify a quadrature of a two-mode squeezed state enhances the measurement of quantum correlations, mitigating losses and improving detection sensitivity.

Contribution

It introduces a novel application of a phase-sensitive amplifier for noiseless pre-amplification of a quadrature in two-mode squeezed states, enhancing quantum correlation measurements.

Findings

Enhanced intensity correlation measurement

Improved intensity-difference squeezing

Effective mitigation of optical losses

Abstract

We demonstrate the ability of a phase-sensitive amplifier (PSA) to pre-amplify a selected quadrature of one mode of a two-mode squeezed state in order to improve the measurement of two-mode quantum correlations that exist before degradation due to optical and detection losses. We use four-wave mixing (4WM) in $^{85}$Rb vapor to generate bright beams in a two-mode squeezed state. One of these two modes then passes through a second 4WM interaction in a PSA configuration to noiselessly pre-amplify the desired quadrature of the mode before loss is intentionally introduced. We demonstrate an enhancement in the measured degree of intensity correlation and intensity-difference squeezing between the two modes.