Optoelectromechanical transducer: Reversible conversion between microwave and optical photons

Quantum states encoded in microwave photons or qubits can be effectively manipulated, whereas optical photons can be coherently transferred via optical fibre and waveguide. The reversible conversion of quantum states between microwave and optical photons will hence enable the distribution of quantum information over long distance and significantly improve the scalability of hybrid quantum systems. Owning to technological advances, mechanical resonators couple to quantum devices in distinctly different spectral range with tunable coupling, and can serve as a powerful interface to connect those devices. In this review, recent theory and experimental progress in the coherent conversion between microwave and optical fields via optoelectromechanical transducers are summarized. The challenges and perspectives in achieving single-photon-level quantum state conversion are also discussed.