Sign up for NPL updates
Sign up for NPL updates

Receive regular emails from NPL to get a glimpse of our activities and see how our experts are informing and influencing scientific debate

Characterising the performance of free-space coupled single-photon detectors

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 such as quantum key distribution and quantum random number generators. Calibration and characterisation of SPDs means that they may be employed and further developed with greater confidence for even more applications.

We aim to bring a degree of confidence to purchasers and developers of SPDs. Our tests will be of interest to those involved in the development of SPDs using new manufacturing techniques or offering the new levels of sensitivity.

NPL can characterise free space SPDs in the spectral range 680 nm – 1050nm and 633 nm by measuring five key metrics:

  1. Traceable detector efficiency measurement - the capability to link the detector response to a traceably measured number of incident photons.

  2. Dark count probability – the mean rate and distribution of detection events in the absence of incident photons.

  3. Dead-time - the time interval after a detection event when the detector is unable to provide a response to an incoming photon.  NB This uses the same measurement as test 2. 

  4. Jitter - the temporal variation in the output signal produced by the detector upon registering an event.

  5. Afterpulse probability – the probability that a detector registers a false detection event in the absence of illumination, conditional on a previous detection event.

Need something else?

More specialised tests to complement this service, as well as calibration 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.

Would you like to speak to one of NPL’s quantum experts?

Contact a quantum expert

Work with us

Our research and measurement solutions support innovation and product development. We work with companies to deliver business advantage and commercial success.
Contact our Customer Services team on +44 20 8943 7070