Quantum nano-photonics with rare-earth-doped materials 

I present quantum nano-photonic devices based on on-chip resonators coupled to rare-earth-ions in crystals.  The rare-earth ions exhibit long coherence times on optical and microwave transitions, which makes them suitable for various quantum light-matter interfaces like quantum memories, single quantum bits, and optical to microwave quantum transducers. We demonstrate on-chip optical quantum memories based on atomic frequency combs and optically addressable quantum bits based on single rare-earth ions where the quantum state can be mapped on Zeeman or hyperfine levels with long coherence time. Our solid-state nano-photonic quantum light-matter interfaces can be integrated with other chip-scale photon source and detector devices for multiplexed quantum and classical information processing at the nodes of future quantum networks.