Near-Maximal Two-Photon Entanglement for Optical Quantum Communication at 2.1μm
Adetunmise C. Dada, Jędrzej Kaniewski, Corin B. E. Gawith, Martin P. J. Lavery, Robert H. Hadfield, Daniele Faccio, Matteo Clerici · Physical Review Applied · 2021
The 2- to 2.5-$\ensuremath{\mu}$m waveband enjoys reduced solar background and low propagation losses in the atmosphere and hollow-core optical fibers. However, harnessing these advantages for optical quantum communications has proved challenging due to a lack of suitable quantum light sources and detectors. The authors demonstrate in this waveband a source of entangled photons that is suitable for generating secure keys for quantum key distribution, and provide device-independent certification of the entanglement. These results are promising for the future implementation of device-independent secure optical quantum communications in daylight.