Characterising the performance of single-photon detectors in the 380 nm to 1050 nm spectral range
Single-photon detectors (SPDs) are used for a range of applications, from sensing applications operating in the single-photon regime to newer applications making use of the peculiar laws of quantum physics, for example security applications such as quantum key distribution and quantum random number generation.
SI-traceable measurements provide confidence in the performance of SPDs so that they may be employed and further developed with greater confidence for even more applications. Our tests would be of interest to industrial end-users and developers, and academia.
An SPD can register two types of detector event – corresponding to the detection of a photon (a detection event), or to processes other than the detection of a photon.
NPL can test and evaluate free-space and fibre-coupled SPDs in the spectral range from 380 nm to 1050 nm by measuring six key metrics traceably to the SI
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Detection efficiency – the probability that the detector will record a detection event when a single photon is incident on its sensing surface.
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Detection efficiency nonlinearity – deviation of detection efficiency from a constant value as a function of input photon rate. This is typically caused by photon arrivals during the detector recovery time (see below).
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Dark count probability – the probability distribution, within a stated time-interval, of an event being registered in the absence of illumination.
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Dead-time and recovery time – dead-time is the time interval after a detector event when the detector is unable to provide a response to an incoming photon. Recovery time includes both dead-time and the time taken for the detector to regain its steady-state detection efficiency (known as the reset time). N.B. This uses the same measurement as for metric 3.
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Jitter – the temporal variation in the output signal produced by the detector upon registering an event.
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Afterpulse probability – the probability that a detector registers an event in the absence of illumination, conditional on a previous detector event.
Spatially mapped measurements over the detector sensing surface can be performed on free-space coupled detectors.
Need something else?
More specialised tests to complement this service, as well as characterisation of fibre-coupled single-photon detectors in the 1550 nm spectral region and at other specific wavelengths, can be provided.
NPL can also perform measurements to characterise the output of single-photon emitters.
Please contact us to discuss your specific requirements.
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