Counting photons needs standardization

Single-photon detectors (SPDs) are now key to research areas ranging from optical communications and astrophysics to cutting-edge information technologies based on quantum physics, such as quantum cryptography and quantum teleportation.

To ensure their accuracy and reliability, SPDs need to be evaluated and compared to some benchmark, ideally a formal standard. NIST researchers are developing methods to do that and have already started to perform custom calibrations for the handful of companies that make SPDs.

The new paper details NIST’s use of conventional technologies to measure SPD detection efficiency, defined as the probability of detecting a photon hitting the detector and producing a measurable outcome. (

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