Experimental study of the spatial distribution of quantum correlations in confocal optical parametric oscillator

An experiment is designed, in the continuous wave regime, in order to produce and analyze images at the quantum level. This system is based on an optical parametric oscillator (OPO), and uses the fact that parametric down-conversion produces signal and idler photons, which are correlated in time and position, all the quality required to produce a quantum image. The crystal is placed in a transverse degenerate optical cavity, which preserves the spatial properties of the parametric process. In this paper, confocal cavity is studied, which is resonant for all transverse modes of the same parity.