Abstract

Quantum optical experiments with emitters in the solid state are usually impeded by the strong phononic coupling to the local environment. Rare earth-doped crystals provide promising solutions because the optically addressable transitions in these systems can exhibit narrow linewidths down to the kilohertz regime at cryogenic temperatures. Hence the hyperfine splitting of the ground state becomes accessible, lending itself to quantum memory applications with Λ-like level schemes. In particular, the shielding effect of the occupied outer electronic states makes it possible to achieve coherence times up to six hours in ensemble experiments [1, 2].

© 2015 IEEE