Patent ID: 7532400
Filing Date: 2009-05-12
Classification: H04B

Abstract:
1. An apparatus for creating entanglement between two atomic ensembles for performing long-distance communication, comprising: a pulsed light source light that generates first and second synchronized light pulses; a first atomic ensemble optically coupled to the light source and having a first collective excitation state, wherein the first light pulse has an energy that can excite the first atomic ensemble so as to generate first photons; a second atomic ensemble optically coupled to the light source and having a second collective excitation state, wherein the second light pulse has an energy that can excite the second atomic ensemble so as to generate second photons; an interferer optically coupled to the first and second atomic ensembles via respective first and second optical paths, the interferer being operable to interfere the first and second photons; first and second filters respectively arranged in the first and second optical paths and respectively operable to prevent light other than the first and second photons from reaching the interferer; first and second single-photon detectors optically coupled to the first and second atomic ensembles and configured to respectively detect the interfered first and second photons so as to establish entanglement between the first and second atomic ensembles; and a photodetector controller operably coupled to the first and second single-photon detectors and configured to control the detection of the interfered first and second photons at the first and second single-photon detectors.