Critical behaviour of coherence and correlation of counterpropagating twin beams

TL;DR

This paper investigates the critical behavior of coherence and correlation in counterpropagating twin beams across different gain regimes, revealing divergence in correlation time and quantum fluctuation slowdown near the MOPO threshold.

Contribution

It provides a detailed analysis of the transition from spontaneous to stimulated pair production in counterpropagating twin beams, highlighting critical phenomena near the MOPO threshold.

Findings

Divergence of correlation time at the MOPO threshold

Slowing down of quantum fluctuations near the threshold

Critical behavior observed across different gain regimes

Abstract

This work analyses the temporal coherence and correlation of twin beams generated in a quasi-phase matched nonlinear crystal in a counterpropagating configuration, ranging from the low-gain regime, where counterpropagating photon pairs are generated spontaneously, to the regime of stimulated pair production, close to the MOPO (Mirrorless Optical Parametric Oscillator) threshold. Here we show a critical divergence of the correlation time and slowing down of quantum fluctuations originating from the feedback mechanism responsible of the MOPO threshold.