Spatial properties of twin-beam correlations at low- to high-intensity transition

TL;DR

This paper demonstrates that spatial correlation functions of photon pairs at the single-photon level correspond to speckle patterns at high intensities, revealing a connection across different light regimes using an intensified CCD camera.

Contribution

It presents the first experimental observation of the correspondence between low- and high-intensity spatial correlations in twin-beam photon pairs.

Findings

Correlation functions match speckle patterns at high intensities

Auto- and cross-correlation behaviors depend on pump parameters

Different acquisition modes reveal the correlation transition

Abstract

It is shown that spatial correlation functions measured for correlated photon pairs at the single-photon level correspond to speckle patterns visible at high intensities. This correspondence is observed for the first time in one experimental setup by using different acquisition modes of an intensified CCD camera in low and high intensity regimes. The behavior of intensity auto- and cross-correlation functions in dependence on pump-beam parameters including power and transverse profile is investigated.