Electrostatic actuation of silicon optomechanical resonators.

Area of Science:

• Optomechanics
• Nanotechnology
• Microelectromechanical systems (MEMS)

Background:

• Cavity optomechanical systems are highly sensitive to mechanical motion, primarily used for measuring thermal noise or optically actuated forces.
• Electrostatic actuation and detection are established techniques for silicon microelectromechanical resonators in filter and oscillator applications.

Purpose of the Study:

• To demonstrate the monolithic integration of electrostatic capacitive actuation with optical sensing in silicon optomechanical disk resonators.
• To observe and characterize electrically excited mechanical motion using optical intensity modulation.

Main Methods:

• Fabrication of silicon optomechanical disk resonators with integrated electrostatic actuation capabilities.
• Utilizing optical waveguides for sensing the mechanical motion.
• Applying an electrical signal at 235 MHz to excite the radial vibrational mode.

Main Results:

• Successful monolithic integration of electrostatic actuation and optical sensing was achieved.
• Electrically excited mechanical motion was detected as optical intensity modulation.
• The radial vibrational mode of the silicon microdisk at 235 MHz was clearly observed.

Conclusions:

• The study demonstrates a viable method for integrating electrostatic actuation with optical sensing in silicon optomechanical systems.
• This approach enables sensitive detection of electrically driven mechanical motion, opening possibilities for new device applications.