Enhancing electromechanical coupling to an optomechanical nanobeam

Optomechanics provides an interesting alternative for low-power information technology.1,2 Nano-optoelectromechanical systems can be a basis for a low power alternative for the ever-expanding needs for information technology. In addition to the pure optomechanical transduction, electromechanical excitation facilitates a way to further modulate the information flow. Electromechanical conversion has been used, for example, in quantum technology in cubit to photon translation.3 The most common way for electromechanical excitation is to use surface acoustic waves (SAW) generated by interdigitated transducers (IDT). The challenge of using IDTs is related to relatively low conversion efficiency of electrical signals to mechanical energy flow in the nanoscale beams.4 In this work, we have investigated the possibility to integrate small bulk acoustic wave (BAW) transducers directly into the optomechanical nanobeams at GHz frequency range to enhance the coupling efficiency and conversion of the electrical signal to the mechanical modes in the beam. FEM simulations predict close to 90 percent conversion efficiency of the electrical power to mechanical energy flow in the nanobeam in optimized structures with isolation from the surroundings using phononic crystals. In addition to simulations, we will tackle the challenges in fabrication and characterization of the devices.