Microwave-to-optical transduction with bulk acoustic resonators

Long-distance quantum networks of superconducting circuit quantum processors are an alluring prospect but are unfeasible without an efficient interface between optical and superconducting qubits. I will present our progress towards building a microwave-to-optical transducer mediated by phonons in a high-overtone bulk acoustic resonator (HBAR). In particular, I will introduce the concept of microwave-to-optical transduction using multiple acoustic modes and show measurements of a transduction-compatible qubit-HBAR device operating in the multi-mode strong coupling regime. This, together with measurements of a transduction-compatible HBAR-optomechanical device, establish bulk acoustic transducers as a promising platform for efficient, low-noise quantum microwave-to-optical transduction.