Microwave-mechanical-optical transducer chip design innovations for noise mitigation

Viewed as resources for quantum information processing, microwave and optical fields offer complementary strengths. We simultaneously couple one mode of a micromechanical oscillator to a resonant microwave circuit and a high-finesse optical cavity, thereby realizing a mechanically mediated electro-optic converter. We have operated this converter at T < 100 mK, and demonstrated conversion efficiency of 47% and added noise of 38 photons [1]. In order to reduce the added noise from mechanical decoherence, we have integrated phononic shielding around the mechanical element. Changing the superconductor to NbTiN further reduces noise in the microwave circuit and conversion process.

[1] Higginbotham, A. P., et. al. “Harnessing electro-optic correlations in an efficient mechanical converter,” Nature Physics 14, 1038–1042 (2018)