Ethereal quantum state stored in solid crystal - physics-math - 12 January 2011 - New Scientist

Ethereal quantum state stored in solid crystal: "Tittel's team started by channelling one photon of an entangled pair into a crystal of lithium niobate doped with ions of thulium. This sends the crystal into a quantum superposition, in which many thulium ions absorb the photon at once and vibrate at different frequencies. The frequencies aren't random, however. Beforehand, the team strategically removed some thulium ions, leaving only those that absorb a particular sequence of frequencies."