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arXiv · 2203.15012

Electron-spin spectral diffusion in an erbium doped crystal at millikelvin temperatures

Milos Rančić·Marianne Le Dantec·Sen Lin·Sylvain Bertaina·Thierry Chanelière·Diana Serrano·Philippe Goldner·Ren Bao Liu·Emmanuel Flurin·Daniel Estève·Denis Vion·Patrice Bertet
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Abstract

Erbium-doped crystals offer a versatile platform for hybrid quantum devices because they combine magnetically-sensitive electron-spin transitions with telecom-wavelength optical transitions. At the high doping concentrations necessary for many quantum applications, however, strong magnetic interactions of the electron-spin bath lead to excess spectral diffusion and rapid decoherence. Here we lithographically fabricate a 4.4 GHz superconducting planar micro-resonator on a $\text{CaWO}_{4}$ crystal doped with Er ions at a concentration of twenty parts per million relative to Ca. Using the microwave resonator, we characterize the spectral diffusion processes that limit the electron-spin coherence of Er ions at millikelvin temperatures by applying 2- and 3-pulse echo sequences. The coherence time shows a strong temperature dependence, reaching 1.3 ms at 23 mK for an electron-spin transition of $^{167}\text{Er}$.

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Milos Rančić, Marianne Le Dantec, Sen Lin, Sylvain Bertaina, Thierry Chanelière, Diana Serrano, Philippe Goldner, Ren Bao Liu, Emmanuel Flurin, Daniel Estève, Denis Vion, Patrice Bertet. 2022-03-28. Electron-spin spectral diffusion in an erbium doped crystal at millikelvin temperatures. https://arxiv.org/abs/2203.15012

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