19 January 2011 Entangled Photon Stored in a Solid

Crystal quantum memory in cryostat (courtesy of Univ. of Geneva).

Prof. Hugues de Riedmatten co-authors a paper in Nature reporting the first evidence of storage of an entangled photon onto a solid. Researchers at the University of Geneva, together with ICFO group leader and ICREA Prof. Hugues de Riedmatten, report the first demonstration of storage of non-classical states of light onto a solid. These results represent an important step towards quantum information technologies based on solid-state devices, in particular for quantum repeaters and long-distance quantum information networks.

The authors demonstrate entanglement between a photon at telecommunication wavelength and a crystal doped with Neodymium ions
at 3 K. This is realized by mapping one photon of an entangled pair onto a collective atomic excitation stored in the crystal. The successful mapping of entanglement is proved by the violation of a Bell inequality.

The research team is completed by PhD students Christoph Clausen and Imam Usmani, Dr Félix Bussières, Dr Nicolas Sangouard, Dr Mikael Afzelius and Prof Nicolas Gisin, all from the University of Geneva. The experiment has been performed at the University of Geneva.