EurekAlert March 27, 2020
Sources of entangled photons have been realized mainly in the near-infrared 700- to 1550-nm spectral window. Using custom-designed lithium niobate crystals for spontaneous parametric down-conversion and tailored superconducting nanowire single-photon detectors an international team of researchers (UK, Japan, Germany) has demonstrated two-photon interference and polarization-entangled photon pairs at 2090 nm. These results open the 2- to 2.5-μm mid-infrared window for the development of optical quantum technologies such as quantum key distribution in next-generation mid-infrared fiber communication systems and future Earth-to-satellite communications much more secure in the future….read more. Open Access TECHNICAL ARTICLE
Generation of polarization entangled photon pairs at a wavelength of 2.1 micrometres. Credit: Michael Kues/PQT