Rare-earth ions in bulk crystals are excellent solid-state quantum systems in quantum information science, owing to the exceptional optical and spin coherence properties. However, the weak fluorescence of single rare-earth ions present a significant challenge for scalability, necessitating the integration into micro-cavities. Thin films serve as a promising material platform for the integration, yet the fabrication without compromising the properties of the materials and rare-earth ions remains challenging. In this work, we fabricate micrometer-thin yttrium aluminum garnet (YAG) films from bulk crystals using ion implantation techniques. The resulting films preserve the single-crystalline structure of the original bulk crystal. Notably, the embedded rare-earth ions are photo-stable and exhibit bulk-like spin coherence properties. Our results demonstrate the compatibility of bulk-like spin properties with the thin-film fabrication technique, facilitating the efficient integration of rare-earth ions into on-chip photonic devices and advancing the applications of rare-earth ions systems in quantum technologies.
@article{arxiv.2503.09147,
title = {Coherence Properties of Rare-Earth Spins in Micrometer-Thin Films},
author = {Zihua Chai and Zhaocong Wang and Xinghang Chen and Quanshen Shen and Zeyu Gao and Junyu Guan and Hanyu Zhang and Ya Wang and Yang Tan and Feng Chen and Kangwei Xia},
journal= {arXiv preprint arXiv:2503.09147},
year = {2025}
}