Rare-earth ion cavity-QED
(Henk Snijders, Dapeng Ding, Michiel de Dood, Dirk Bouwmeester)

cqed rareearth Figure:

We investigate rare-earth ions in optical ring cavities. Rare-earth ions enable inner-shell transitions that are shielded from the environment, leading to exceptional coherence properties. Such systems are ideal quantum memories, and we study how integrated optical cavities can be used to enhance interaction of single photons with the quantum memory.