Polarization-entangled photon pair source using beam displacers and thin crystals

Abstract

We present an experimental implementation of a polarization-entangled photon pair source based on beam displacers. The down-converted photons are emitted via spontaneous parametric down-conversion in a non-degenerate and type-0 process. We obtain a state fidelity of $F=0.975\pm0.004$ and violate a Clauser-Horne-Shimony-Holt inequality with $S=2.75\pm0.01$. Our source also uses thin crystals for applications in quantum imaging, taking advantage of the large number of spatial modes. We estimate that our source could produce 550$\pm$12 spatial modes.