Photons that are suitable for quantum communication can be emitted from solid materials.

A roadblock to building quantum information networks is the need for streams of identical photons that oscillate in sync with each other. Such streams are produced by lasers, but integrating these with electronics is difficult.

Now Mete Atatüre at the University of Cambridge, UK, and his colleagues report that they have generated such a stream from semiconducting nanocrystals, or quantum dots. These dots exhibit a phenomenon called resonance fluorescence, in which emitted photons resonate with one another, and so oscillate in sync.

Nature Commun. 4, 1600 (2013)