title: Atom-resonant heralded single photons by interaction-free measurement.
abstract: We demonstrate the generation of rubidium-resonant heralded single photons for quantum memories. Photon pairs are created by cavity-enhanced down-conversion and narrowed in bandwidth to 7 MHz with a novel atom-based filter operating by "interaction-free measurement" principles. At least 94% of the heralded photons are atom-resonant as demonstrated by a direct absorption measurement with rubidium vapor. A heralded autocorrelation measurement shows g(c)(2)(0)=0.040±0.012, i.e., suppression of multiphoton contributions by a factor of 25 relative to a coherent state. The generated heralded photons can readily be used in quantum memories and quantum networks.
authors.affiliation: ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain.
authors.forename: Florian
authors.initials: F
authors.lastname: Wolfgramm
authors.forename: Yannick A
authors.initials: YA
authors.lastname: de Icaza Astiz
authors.forename: Federica A
authors.initials: FA
authors.lastname: Beduini
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cerè
authors.forename: Morgan W
authors.initials: MW
authors.lastname: Mitchell