Eur. Phys. J. Special Topics 199, 111-125 (2011)
https://doi.org/10.1140/epjst/e2011-01507-y

Regular Article

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

¹ Dipartimento di Fisica, Sapienza Università di Roma, 00185 Roma, Italy
² Istituto Nazionale di Ottica (INO-CNR), Largo E. Fermi 6, 50125 Firenze, Italy
³ Dipartimento di Ingegneria dell’Informazione, Università degli Studi Padova, 35131 Padova, Italy
⁴ Dipartimento di Fisica Teorica, Università degli Studi di Torino, via P. Giuria, 1, 10125 Torino, Italy
⁵ Department of Quantum Electronics, Vilnius University, Saulėtekio Avenue 9, Building 3, LT-10222 Vilnius, Lithuania
⁶ Regional Centre of Advanced Technologies and Materials, Joint Laboratory of Optics of Palacky University and Institute of Physics of Academy of Sciences of the Czech Republic, Faculty of Science, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic
⁷ Dipartimento di Fisica e Matematica, Università degli Studi dell’Insubria, via Valleggio 11 Como, Italy
⁸ Department of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory, 119991 Moscow, Russia
⁹ Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche and C.N.I.S.M., U.d.R. Como, Italy

^a e-mail: paolo.mataloni@uniroma1.it

Received: 29 August 2011
Revised: 4 October 2011
Published online: 7 December 2011

Abstract

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 preparation 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 a non-locality test obtaining a high violation of the CHSH inequality.