Purification of Single-Photon Entanglement
D. Salart, Olivier Landry, Nicolas Sangouard, Nicolas Gisin, H. Herrmann, Bruno Sanguinetti, Christoph Simon, W. Sohler, Rob Thew, A. Thomas, Hugo Zbinden · Physical Review Letters · 2010
Single-photon entanglement is a simple form of entanglement that exists between two spatial modes sharing a single photon. Despite its elementary form, it provides a resource as useful as polarization-entangled photons and it can be used for quantum teleportation and entanglement swapping operations. Here, we report the first experiment where single-photon entanglement is purified with a simple linear-optics based protocol. In addition to its conceptual interest, this result might find applications in long distance quantum communication based on quantum repeaters.