  We demonstrate Einstein-Podolsky-Rosen (EPR) entanglement by detecting purely
spatial quantum correlations in the near and far fields of spontaneous
parametric down-conversion generated in a type-2 beta barium borate crystal.
Full-field imaging is performed in the photon-counting regime with an
electron-multiplying CCD camera. The data are used without any postselection,
and we obtain a violation of Heisenberg inequalities with inferred quantities
taking into account all the biphoton pairs in both the near and far fields by
integration on the entire two-dimensional transverse planes. This ensures a
rigorous demonstration of the EPR paradox in its original position momentum
form.
