title: Atomic-vapor-based high efficiency optical detectors with photon number resolution.
abstract: The ability to detect very weak optical fields with high efficiency (>99%) and to distinguish the number of photons in a given time interval is a very challenging technical problem with enormous potential payoffs in quantum communications and information processing. We propose to employ an atomic vapor as the active medium, prepared in a specific quantum state using laser radiation. The absorption of a photon will be aided by a dressing laser, and the presence or absence of an excited atom will be detected using the "cycling transition" approach perfected for ion traps. By incorporating an appropriate up-conversion scheme, our method can be applied to a wide variety of optical wavelengths.
authors.affiliation: Theoretical Division T-4, University of California, Los Alamos National Laboratory, MS B-283, P.O. Box 1663, Los Alamos, New Mexico 87545, USA. dfvj@t4.lanl.gov
authors.forename: Daniel F V
authors.initials: DF
authors.lastname: James
authors.forename: Paul G
authors.initials: PG
authors.lastname: Kwiat