title: Single-photon generation from stored excitation in an atomic ensemble.
abstract: Single photons are generated from an ensemble of cold Cs atoms via the protocol of Duan et al. [Nature (London), ()]]. Conditioned upon an initial detection from field 1 at 852 nm, a photon in field 2 at 894 nm is produced in a controlled fashion from excitation stored within the atomic ensemble. The single-quantum character of field 2 is demonstrated by the violation of a Cauchy-Schwarz inequality, namely w(1(2),1(2)|1(1))=0.24+/-0.05 not > or = 1, where w(1(2),1(2)|1(1)) describes the detection of two events (1(2),1(2)) conditioned upon an initial detection 1(1), with w-->0 for single photons.
authors.affiliation: Norman Bridge Laboratory of Physics 12-33, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: C W
authors.initials: CW
authors.lastname: Chou
authors.forename: S V
authors.initials: SV
authors.lastname: Polyakov
authors.forename: A
authors.initials: A
authors.lastname: Kuzmich
authors.forename: H J
authors.initials: HJ
authors.lastname: Kimble