Single photons on pseudodemand from stored parametric down-conversion

The Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723(Dated: February 9, 2008)We describe the results of a parametric down-conversion experiment in which the detection of onephoton of a pair causes the other photon to be switched into a storage loop. The stored photoncan then be switched out of the loop at a later time chosen by the user, providing a single photonfor potential use in a variety of quantum information processing applications. Although the storedsingle photon is only available at periodic time intervals, those times can be chosen to match thecycle time of a quantum computer by using pulsed down-conversion. The potential use of the storageloop as a photonic quantum memory device is also discussed.I. INTRODUCTION