Sub‐MHz homogeneous linewidth in epitaxial Y ₂ O ₃ : Eu ³⁺ thin film on silicon

Thin films provide nanoscale confinement together with compatibility with photonic and microwave architectures, making them ideal candidates for chip-scale quantum devices. In this work, we propose a thin film fabrication approach yielding the epitaxial growth of Eu 3+ doped Y 2 O 3 on silicon. We c