Abstract

Spontaneous down conversion (SPDC) occurs in a nonlinear crystal when a pump photon splits in a pair of signal and idler photons. Even if the number of pairs fluctuates, the difference between the signal and idler output photon numbers is zero in an ideal experiment. Jedrkiewicz et al. [1], performed the first experimental demonstration of sub-shot noise behaviour of spatial fluctuations of the signal-idler difference. Recently, we proposed [2], a more direct demonstration without any detector noise subtraction, by detecting single photons in low light level images with an electron multiplying CCD camera (EMCCD). We experimentally demonstrated that opposite spatial fluctuations of SPDC radiation are correlated in the quantum regime. The statistic was perfonned over 180 angular sectors of 240 pixels for non collinear phase matching. Here, correlations between pixels are presented for collinear phase matching.

© 2009 IEEE