Study of spatial behaviour of photon pairs generated by parametric down-conversion

Lorenzo M. Procopio, Óscar Rosas-Ortiz, Víctor Velázquez +4 more

T. Yamaguchi, Ryōsuke Shimizu, Yasuyoshi Mitsumori +2 more

Polarization entanglement of photons provides a superior environment to demonstrate quantum info-communication protocols. Thus far, several methods using parametric down-conversion process have been realized to generate polarization-entangled photon pairs. In this report, we propose a novel method to generate polarization entanglement from spatially correlated photon pairs and demonstrate its experimental verification.

Chung Ki Hong

So-Young Baek, Fumihiro Kaneda, Yasuyoshi Mitsumori +1 more

We present our recent progress on developing a parametric down-conversion source producing highly entangled photons in spatial mode toward quantum-enhanced spa-tial measurements. The degree of transverse spatial entanglement is engineered and characterized.

G. Brida, Marco Genovese, Carlo Novero

Peter J. Mosley, Andreas Christ, A. Eckstein +1 more

We present a study of the propagation of higher-order spatial modes in a waveguided parametric down-conversion photon-pair source. Observing the multimode photon-pair spectrum from a periodically poled KTiOPO(4) waveguide allowed us to isolate individual spatial modes through their distinctive spectral properties. We have measured directly the spatial distribution of each mode of the photon pairs, confirming the findings of our waveguide model, and demonstrated by coincidence measurements that the total parity of the modes is conserved in the nonlinear interaction. Furthermore, we show that we can combine the advantages of a waveguide source with the potential to generate spatially entangled photon pairs as in bulk-crystal down-converters.