High degree of entanglement and nonlocality of a two-photon state generated at 532 nm

In the last years the attention of the scientific community on the generation of entangled states has constantly increased both for their importance in the foundation of quantum mechanics and for their application in the quantum computation and communication field. To these aims high quality of generated states is required. A standard procedure to produce entangled photons pairs is spontaneous down conversion process in nonlinear crystals. In this paper we report prepa- ration of quantum entangled states using CW laser at 266 nm pumping the standard Kwiat’s source. We have been able to generate the full set of Bell’s states with very high purity, fidelity and concurrence which have been estimated using standard tomography procedure. To proof the high degree of achieved entanglement, we performed non-locality test obtaining a high violation of the CHSH inequality.