Strong light modulation using acoustic phonons and quantum dots

Fast and efficient modulation of light is crucial for high-speed communications as well as building a long-distance network of quantum processors. So far, electro-optic modulators have been at the forefront of these technologies due to their scalability and ability to perform at above 100s of GHz speed. Recently, optomechanical approaches have gained attention owing to their efficient microwave-to-optical conversion, importance for low-energy modulation and quantum transduction. These approaches use mechanical vibrations (phonons) as an intermediate platform that couples efficiently to both electrical and optical photons. Acoustic phonons on the surface of GaAs can couple to both, electrical circuits and light, due to the material’s piezoelectric response and ability to host single-photon emitters in form of quantum dots, respectively. We show low-power phase modulation of resonant light scattered from these quantum dots, using cavity-enhanced surface acoustic waves, with V_π as low as 50 mV. These demonstrations pave the way for building an optical network for superconducting qubits and distributed quantum computation.