An Optomechanical Transducer for Quantum State Transfer Between Infrared Light and Microwave. Part I: Fabrication*

Optomechanical systems provide a very interesting approach to frequency conversion between the microwave and optical domains, and in particular could provide a means to couple superconducting qubits to infrared telecommunications-wavelength signals. This capability would provide a compelling means to long-distance quantum communication. In this talk, we will describe our fabrication process, which includes how we combine an aluminum nitride-based interdigital transducer (IDT) with a silicon-based one-dimensional optomechanical resonator, using a multi-layer process combining thin-film deposition and etching with patterning provided by a combination of optical and electron-beam lithography. At the end of the process, the structures are suspended in order to have desired frequency conversion. This combination of materials and design promises the necessary optomechanical and electromechanical coupling rates that would allow us to efficiently convert signals between infrared light and microwave electrical signals. With suitable operation at low temperatures, these devices could serve to couple superconducting qubits to infrared light in a quantum-coherent fashion.