Broadband Waveguide Quantum Memory for Entangled Photons
Erhan Sağlamyürek, Neil E. Sinclair, Jeongwan Jin +7 more
For advanced applications in quantum information and communication the reversible transfer of quantum information between light and matter is essential. A key property of such a light-matter quantum interface is the faithful mapping of entanglement. We report the reversible transfer of photon-photon entanglement into entanglement between a photon and a collective atomic excitation in a thulium-doped lithium niobate waveguide. We use an Atomic Frequency Comb (AFC) memory protocol yielding a 5 GHz acceptance bandwidth of our memory. We reconstruct the bi-photon quantum state before and after the reversible transfer and asses the entanglement-preserving nature of our memory. We demonstrate a near perfect mapping of the entangled state. Additionally, we measure a violation of the CHSH Bell inequality before and after storage, thus directly verifying the sufficiency of the entanglement for quantum communication.
International Conference on Quantum Information•Jan 1, 2011•52 citations