Non Locality in a Micro-Macroscopic Photon System

A Bell test is performed on a Micro‐Macroscopic photon system obtained by parametric amplification of a spin‐1 entangled photon state. The optical parametric amplification leads to the creation of a Micro‐Macroscopic entangled system consisting of N≃3.5×104. The performed Bell’s inequality non locality test involves the adoption of a positive operator valued measurement (POVM) strategy for a sharper identification of the amplified states. This is obtained through a local filtering technique and the experimental data are found to violate the Bell’s inequality albeit with a loophole similar to the detection efficiency one in photon counting experiments.