QuReP News

Storage of entanged photons in a crystal

Nature logoWe have demonstrated that photons from entangled pairs can be stored in one of our quantum memories without losing the entanglement. This proves experimentally that the atomic frequency comb storage protocol developed at the GAP-Optique is indeed suited for the use in quantum repeaters. The results have now been published in Nature [1].

The results of the experiment are threefold. It demonstrates, for the first time, the successful storage of heralded single photons in a solid-state memory with storage-and-retrieval efficiencies surpassing 20% for the shortest storage time of 25ns. Additionally, we show that the non-classical nature of the intensity correlations between two photons in a pair are preserved after the storage and retrieval process, with storage times up to 200ns. Finally, a violation of a Bell inequality by more than three standard deviations proves that the storage process creates a light-matter entangled state. These results represent the first successful mapping of energy-time entangled photons onto a quantum memory, and we note that the intrinsic multimode capability makes the AFC perfectly suitable for storing this kind of entanglement.

1. C. Clausen et al., Nature Online (2011)

Also in the media:

An article (including comments by Mikael Afzelius and Wolfgang Tittel) in Physics World: Quantum communications boosted by solid memory devices

An article in New Scientist: Ethereal quantum state stored in solid crystal
For further news, see our Press page