Erlangen 2018 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 47: Quantum Information (Quantum Repeater)

Q 47.5: Vortrag

Mittwoch, 7. März 2018, 15:15–15:30, K 1.020

Towards efficient quantum memories at telecom wavelength — Benjamin Merkel, Lorenz Weiß, Natalie Wilson, Valentin Crépel, Andreas Gritsch, and •Andreas Reiserer — MPI of Quantum Optics, Garching, Germany

Global-scale quantum networks require efficient interfaces between long-lived memory nodes and photons at a telecommunications wavelength, where loss in optical fibers is minimal. In this context, Erbium ions doped into suited crystals are a promising candidate, as they exhibit a coherent optical transition at 1.5 µm and spin lifetimes exceeding 100 ms. Unfortunately, such long coherence times require a low dopant concentration to avoid ion-ion interactions, which puts a limit on the achievable efficiency of quantum memories. In our group, we plan to overcome this challenge by embedding Erbium-doped crystals into high-finesse optical resonators. In initial experiments with crystals of low dopant ion concentration, we have observed spin lifetimes of up to 0.5 s. By applying microwave pulses, we explore the potential of dynamical decoupling to extend the coherence time to this lifetime limit. In addition, we investigate the use of nuclear spins as a route to longer memory times. Finally, we have inserted Erbium-doped crystals into optical cavities that give access both to the single-ion Purcell regime and to the collective strong coupling regime. This opens unique perspectives for the implementation of efficient quantum memories for telecom photons.