Study of coherent microwave-to-optical transduction using on-chip rare-earth ion devices*

Quantum transducers will allow application-specific quantum hardware to accelerate the realization of large scale networks of entangled qubits. Rare-earth ions (REIs) in transparent crystals are one system suited to the development of quantum transducer technologies because of their ability to transfer entanglement between their highly coherent optical, electron-spin, and nuclear spin transitions. To harness this appeal, it is important to realize an integrated, on-chip architecture for REI quantum technologies to facilitate network connectivity with other quantum systems.

We will present the fabrication and characterization of on-chip REI devices based on ¹⁷¹Yb-doped yttrium orthovanadate (¹⁷¹Yb:YVO₄). The devices combine nanophotonic waveguides or cavities with planar microwave waveguides. Waveguides allow spectroscopic measurements of the optical and spin transitions over broad frequency ranges facilitating studies in a variety of applied magnetic fields. We will report on the potential of this architecture for microwave to optical transduction, including its performance at zero-magnetic field, and suggest avenues for increasing the transduction efficiency.