TYPE-II PARAMETRIC DOWNCONVERSION IN THE WIGNER-FUNCTION FORMALISM - ENTANGLEMENT AND BELLS INEQUALITIES

We continue the analysis of our previous papers that were devoted to t ype I parametric downconversion, the extension to type II being straig htforward. We show that entanglement, in the Wigner representation, is merely a correlation that involves both signals and vacuum fluctuatio ns. An analysis of the detection process opens the way to a complete d escription of parametric dawnconversion in terms of pure Maxwell elect romagnetic waves. (C) 1998 Optical Society of America [S0740-3224(98)0 1205-3].