Linear and nonlinear capacitive coupling of electro-opto-mechanical   photonic crystal cavities
  We fabricate and characterize a microscale silicon electro-opto-mechanical system whose mechanical motion is coupled capacitively to an electrical circuit and optically via radiation pressure to a photonic crystal cavity. To achieve large electromechanical interaction strength, we implement an inverse shadow mask fabrication scheme which obtains capacitor gaps as small as 30 nm while maintaining a silicon surface quality necessary for minimizing optical loss. Using the sensitive optical read-out of the photonic crystal cavity, we characterize the linear and nonlinear capacitive coupling to the fundamental 63 MHz in-plane flexural motion of the structure, showing that the large electromechanical coupling in such devices may be suitable for realizing efficient microwave-to-optical signal conversion. 
Alessandro Pitanti, Johannes M. Fink, Amir H. Safavi-Naeini, Chan U.   Lei, Jeff T. Hill, Alessandro Tredicucci and Oskar Pa...
physics.optics