Continuous variable entanglement of counter-propagating twin beams

TL;DR

This paper investigates the continuous-variable entanglement of counter-propagating twin beams generated in a mirrorless optical parametric oscillator, highlighting differences with co-propagating geometries and analyzing their quadrature and photon-number correlations.

Contribution

It provides a detailed analysis of the entanglement properties of counter-propagating twin beams, including bandwidth and stability comparisons with co-propagating setups.

Findings

Significant bandwidth difference between counter-propagating and co-propagating geometries.

Distinct stability characteristics with respect to phase-angle.

Analysis of the temporal bandwidth of intensity squeezing.

Abstract

This work describes the continuous-variable entanglement of the counter-propagating twin beams generated in a Mirrorless Optical Parametric Oscillator below threshold, encompassing both their quadrature and photon-number correlation. In the first case, a comparison with the single-pass co-propagating geometry outlines the huge difference of the bandwidth involved and a completely different stability of the two sources with respect to the phase-angle. In the second case, stimulated by the critical divergence of the correlation time evidenced by Corti et al., we address the issue of the temporal bandwidth of the intensity squeezing.