title: Subnatural-linewidth polarization-entangled photon pairs with controllable temporal length.
abstract: We demonstrate an efficient experimental scheme for producing polarization-entangled photon pairs from spontaneous four-wave mixing (SFWM) in a laser-cooled (85)Rb atomic ensemble, with a bandwidth (as low as 0.8 MHz) much narrower than the rubidium atomic natural linewidth. By stabilizing the relative phase between the two SFWM paths in a Mach-Zehnder interferometer configuration, we are able to produce all four Bell states. These subnatural-linewidth photon pairs with polarization entanglement are ideal quantum information carriers for connecting remote atomic quantum nodes via efficient light-matter interaction in a photon-atom quantum network.
authors.affiliation: Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China.
authors.forename: Kaiyu
authors.initials: K
authors.lastname: Liao
authors.affiliation: Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yan
authors.affiliation: Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China.
authors.forename: Junyu
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Shengwang
authors.initials: S
authors.lastname: Du
authors.affiliation: Laboratory of Quantum Engineering and Quantum Materials, School of Information and Photoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China.
authors.forename: Zhi-Ming
authors.initials: ZM
authors.lastname: Zhang
authors.affiliation: Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, China and National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Shi-Liang
authors.initials: SL
authors.lastname: Zhu