Jean Etesse
Institut de Physique de Nice
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Quantum memories in rare-earth ion-doped crystals
Photonic quantum memories are essential building blocks of quantum networks, thanks to the ability they offer to synchronize quantum data. Key figures of merit of such devices include efficiency, fidelity, storage time and multimodality. Rare-earth ion-doped (REID) crystals represent a unique system to push simultaneously these performances in a single platform, given their record spin coherence times (more than 6 hours!) and large absorption bandwidth. Moreover, their solid-state nature allows for the shaping of complex structures including waveguides, opening the way to integrated photonics embedding quantum memories.
In this presentation, I will first describe an ensemble-based rephasing protocol, the ‘Atomic Frequency Comb’ protocol, and show how it allows for the multimode long-duration storage of photonic pulses of light at the quantum level. Then, I will describe the mechanisms that currently limit the storage times in some REID crystals. Finally, I will briefly present recent achievements in the development of integrated quantum memories in these materials, including devices we are currently fabricating at Institut de Physique de Nice.
