Abstract

NIST has ongoing efforts to advance single-photon and photon-number-resolving detectors, single-photon and entangled-photon sources, and the metrology of those devices for applications in quantum communications and quantum information processing. The detector efforts include improved circuitry for both Si and InGaAs single-photon avalanche photodiodes to improve efficiency and count rate, while reducing dark counts and afterpulsing, and to improve the compatibility of these devices with gigahertz-rate single and correlated-photon sources. We are also working on improved processing of the output signal from photon-number-resolving detectors to maximize the information extracted. Another scheme uses active optical switching and an array of detectors to increase allowable detection rates and reduce detection deadtime. Source efforts include bright and efficient sources based on parametric downconversion and fourwave mixing. Metrology efforts in the photon counting regime include both conventional metrology tied to detector-based standards and correlated-photon metrology using photon pair sources, with our ultimate goal to make higher accuracy metrology available to the photon-counting community at large.