Entangled photon stored in a solid

27 January 2011

Our recent experiment done at the University of Geneva, reporting the storage of an entanglement photon  into a doped crystal has been published in Nature.

We 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. 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.

Experimental set-up.

Fig. The experimental set-up can be divided into three parts: the Nd:Y2SiO5 crystal serving as quantum memory, the laser system for the preparation of the AFC in the crystal, and the source of entangled photons with associated spectral filter.

The paper has been highlighed in a News&Views article by Dr. Jevon Longdell.

See also the news on GapOptique’s website.

Ref: Quantum storage of photonic entanglement in a crystal
Christoph Clausen, Imam Usmani, Félix Bussières, Nicolas Sangouard, Mikael Afzelius, Hugues de Riedmatten & Nicolas Gisin
Nature 469,508–511,