Simple direct measurement of nonclassical joint signal–idler photon-number statistics and the correlation area of twin photon beams

Abstract

The measurement of the joint signal–idler photon-number distribution of a field obtained from spontaneous parametric downconversion using an intensified CCD camera is presented. It is shown that a classicality criterion is violated directly by the measured data. Characteristic dimensions of the area of correlation are determined in the same experimental set-up.