Spatial　quantum　optical　fluctuations　are　studied　because　of　new　potential　applications　of　quantum　optical　procedures　in　parallel　processing　and　multi-channel　operation.　The　process　of　parametric　down-conversion　(PDC)　is　particularly　suitable　for　the　study　of　spatial　effects,　because　of　its　large　emission　bandwidth　in　the　spatial　frequency　domain.　Recent　theoretical　investigations　done　for　an　arbitrary　gain　[1]　have　predicted　multi-mode　spatial　correlations　below　shot-noise　between　several　portions　of　the　signal　and　idler　emission　cones　that　correspond　to　phase　conjugate　modes,　when　the　size　of　the　detection　area　in　the　far　field　is　of　the　same　order　or　larger　than　the　coherence　area　of　the　radiation.　Here　we　report　on　the　first　quantum　spatial　measurements　of　PDC　radiation　performed　by　using　a　2　Hz-pulsed　high-power　laser　(1GW-1ps)　[2].　This　enables　us　to　tune　the　PDC　to　the　high-gain　regime　while　keeping　a　large　pump　beam　size　(∼1　mm).　The　huge　number　of　transverse　modes　[roughly　given　by　the　ratio　between　i)　the　angular　bandwidth　of　the　PDC　and　ii)　the　inverse　of　the　near　field　gain　area]　allows　us　to　concentrate　on　a　portion　of　the　parametric　fluorescence　close　to　the　collinear　direction　and　within　a　narrow　frequency　bandwidth　around　degeneracy.　This　portion　still　contains　a　large　(＞1000)　number　of　pairs　of　signal/idler　correlated　phase-conjugate　modes,　propagating　at　symmetrical　directions　with　respect　to　the　pump　in　order　to　fulfill　the　phase-matching　constraints.　The　statistical　ensemble　averaging　necessary　for　the　quantum　measurement　is　solely　done　over　the　spatial　replicas　(pairs　of　symmetrical　spots)　for　each,　single,　pump-laser　pulse.　The　single-shot　measurements　performed　by　means　of　a　high　efficiency　CCD　reveal　sub-shot-noise　spatial　correlations　for　a　PDC　gain　corresponding　to　the　detection　of　up　to　100　photoelectrons　(pe)　per　mode.　The　observed　transition　from　the　quantum　to　the　classical　regime　is　attributed　to　a　narrowing　of　the　near-field　gain　profile　that　occurs　at　very　high　gain　in　presence　of　a　bell-shaped　pump　beam,　implying　a　broadening　of　the　far-field　coherence　area.　We　therefore　expect　to　go　below　shot-noise　for　higher　gain　by　looking　at　correlation　between　groups　of　binned　pixels.　©　2005　IEEE.