Characterization of Er³⁺:YVO₄ for microwave to optical transduction

Quantum transduction between microwave and optical frequencies is important for connecting superconducting quantum platforms within a quantum network. Ensembles of rare-earth ions are promising candidates to achieve this conversion due to their collective coherence properties at microwave and optical frequencies. Erbium ions are of particular interest because of their telecom wavelength optical transitions that are compatible with fiber communication networks and components. Here, we report the optical and electron spin properties of erbium-doped yttrium orthovanadate (Er³⁺:YVO₄), including high-resolution optical spectroscopy, electron paramagnetic resonance studies, and an initial demonstration of microwave to optical conversion of classical fields. The highly absorptive optical transitions and narrow ensemble linewidths make Er³⁺:YVO₄ promising for magneto-optic quantum transduction.