title: Statistics of narrow-band single photons for quantum memories generated by ultrabright cavity-enhanced parametric down-conversion.
abstract: Narrow-band single photons represent an important resource for quantum memories due to their efficient interaction with atomic resonances. In this Letter, we report on the generation of photons with 3 MHz linewidth by cavity-enhanced parametric down-conversion and demonstrate direct proof of their single-photon character by detection of heralding idler photons. Compared to a Poissonian source, a suppression of higher-order photon numbers by nearly 2 orders of magnitude could be achieved. Moreover, the brightness of our source exceeds previous realizations by more than a factor of 100.
authors.affiliation: Nano-Optics Group, Physics Department, Humboldt University, D-10117 Berlin, Germany. matthias.scholz@physik.hu-berlin.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Scholz
authors.forename: Lars
authors.initials: L
authors.lastname: Koch
authors.forename: Oliver
authors.initials: O
authors.lastname: Benson