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RESEARCH
“That’s thus far been one of the key stumbling blocks to ANALYSIS
advancing daylight quantum key distribution in free TRENDS
space - if the wavelength that your photon detector is
sensitive to is too close to the wavelength of the
photons that are coming towards it from the sun, your
detector can easily be blinded.”
This breakthrough has benefited from the cutting-edge
expertise of UK photonics companies. In partnership
with Covesion Ltd, Dr Clerici and his team have
engineered a nonlinear crystal made from lithium
niobite, suitable for operating at 2.1 micrometers. The
entangled photon pairs are generated when short
pulses of light from a laser source, provided for this systems will need to operate in cloudy environments
research by Chromacity Ltd, pass through the crystal. and during the day as well as the night. Longer
wavelength photon counting systems are the vital
The entangled photons, which have half the energy of technology required to enable this, and so the
their parent photon, and which are perfectly correlated breakthrough reported by our colleagues in Glasgow
in polarization, are then sent towards a specially will underpin commercially viable QKD applications.”
designed superconducting nanowire single-photon
detector. The paper, titled ‘Two-photon Quantum Interference
and Entanglement at 2.1 μm’, is published in Science
Dr Adetunmise Dada, Research Associate at the Advances. Researchers from the University of Glasgow
University of Glasgow, added: “Along with our collaborated with colleagues from the Universities of
collaborators in academia and industry, we’ve found a Southampton and Strathclyde in the UK, Kobe
way to reliably create high-quality paired photons at a University and the National Institute of Information and
new wavelength, making them well-suited to use in Communications in Japan, Leibniz University Hannover
quantum communications. Our next step is to take our in Germany, Covesion Ltd and Chromacity Ltd.
system out of the lab and start to test it under realistic
outdoor conditions. It’s an exciting stage to be at and The research was supported by funding from Innovate
we’re looking forward to seeing where we can take it UK, UKRI, EPSRC, the Royal Society, Leverhulme
from here.” Trust, Royal Academy of Engineering, the European
Research Council, MEXT (Japan) and BMBF
Andy Vick, Head of Disruptive Space Technologies at (Germany). (Source: University of Glasgow) ◊
UK’s RAL Space and not involved in the research,
commented: “Commercial quantum key distribution By MediaBUZZ
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