(ZDnet) A team of researchers at the University of Glasgow has published details of a new way to reliably create particles that are well-suited to use in quantum communications, which could lead to the unhackable communication protocols that have long been pitched as one of the most useful applications of the technology.
The scientists generated entangled photons, a method that applies one of the most intriguing properties of quantum physics. Entanglement is a phenomenon that occurs when two quantum particles become inextricably linked, which means that the way one behaves immediately affects the other, regardless of the distance between them.
Photon entanglement, in itself, is not new. In fact, the technology is already used for secure communication over thousands of kilometres, for example for satellite-to-ground or satellite-to-satellite communications. Until now, however, photons were generated in a specific wavelength – between 700 and 1,550 nanometres – which means that the light produced is close to the brightness of the sun.
Generating photons at two micrometres had never been demonstrated before. A major challenge for the researchers was to get their hands on the appropriate technology to conduct their experiment. A partnership with technology manufacturer Covesion and the National Institute of Communications and Technology (NICT) in Tokyo, Clerici and his team engineered a nonlinear crystal that was suitable for operating at two micrometers. Photons are generated when short pulses of light from a laser source pass through the crystal.

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