Abstract: A system and method of implementing quantum key distribution are provided that possess increased data rates and enhanced security. These increased data rates are provided through the use of biphotons. Through encoding bits of information on the intra-biphoton delay time and enabling separate polarization bases for each of the photons comprising each biphoton, the system and method increase data bandwidth available for quantum key distribution.

Abstract: A system and method of detecting entangled photon pairs, each pair including a signal photon and an idler photon, is disclosed. Entangled photon pairs are provided having an entanglement time and an entanglement area selected to substantially increase an associated entangled two-photon cross-section of an associated target medium. The entangled photon pairs are also selected to have an energy distribution between the signal photon and the idler photon to substantially decrease an associated random two-photon absorption cross section of the target medium. The entangled photon pairs are directed to the target medium, and at least one entangled-photon pair being absorbed by the target medium is detected. The techniques for detecting entangled photons may be adapted to accommodate hiding information in entangled photons. That is, these techniques may be used for quantum steganography.

Abstract: A system for and method of efficiently generating high-intensity entangled photons are disclosed. The system and method may advantageously use an optical ring cavity that is resonant in the frequency of a pump light beam.

Abstract: A system and method of detecting entangled photon pairs, each pair including a signal photon and an idler photon, is disclosed. Entangled photon pairs are provided having an entanglement time and an entanglement area selected to substantially increase an associated entangled two-photon cross-section of an associated target medium. The entangled photon pairs are also selected to have an energy distribution between the signal photon and the idler photon to substantially decrease an associated random two-photon absorption cross section of the target medium. The entangled photon pairs are directed to the target medium, and at least one entangled-photon pair being absorbed by the target medium is detected. The techniques for detecting entangled photons may be adapted to accommodate hiding information in entangled photons. That is, these techniques may be used for quantum steganography.

Abstract: An arrangement for counting detectable events, such as scintillation events in a specimen sample utilizes first and second detector elements arranged on either side of the sample. The first detector is of the type which is able to produce information relative to the position of the event in the sample. The second detector generates a timing signal responsive to the detected event. In certain embodiments, the first detector also issues a timing signal in response to the detection of the event, and both timing signals are compared for temporal coincidence, whereupon circuitry for determining the position of the detectable event is triggered. The total energy of the event can be obtained from addition of the analog amplitudes of the timing signals. In certain embodiments, the second detector also produces position information, and the first and second detectors may provide respective coordinate values of a coordinate pair.