Solid-state atomic defects with optical transitions in the telecommunication bands, potentially in a nuclear spin free environment, are important for applications in fiber-based quantum networks. Erbium ions doped in CeO2 offer such a desired combination. Here we report on the optical homogeneous linewidth and electron spin coherence of Er3+ ions doped in CeO2 epitaxial film grown on a Si(111) substrate. The long-lived optical transition near 1530 nm in the environmentally-protected 4f shell of Er3+ shows a narrow homogeneous linewidth of 440 kHz with an optical coherence time of 0.72 μs at 3.6 K. The reduced nuclear spin noise in the host allows for Er3+ electron spin polarization at 3.6 K, yielding an electron spin coherence of 0.66 μs (in the isolated ion limit) and a spin relaxation of 2.5 ms. These findings indicate the potential of Er3+:CeO2 film as a valuable platform for quantum networks and communication applications.
@article{arxiv.2309.16785,
title = {Optical and spin coherence of Er$^{3+}$ in epitaxial CeO$_2$ on silicon},
author = {Jiefei Zhang and Gregory D. Grant and Ignas Masiulionis and Michael T. Solomon and Jasleen K. Bindra and Jens Niklas and Alan M. Dibos and Oleg G. Poluektov and F. Joseph Heremans and Supratik Guha and David D. Awschalom},
journal= {arXiv preprint arXiv:2309.16785},
year = {2024}
}