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


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. This process is considered one of the most useful instruments in research of basic laws of nature as well as practical application of quantum optics and quantum information processing.

Speckle patterns images obtained in nonlinear high-intensity process.