The force exerted by light is small and generally insignificant. However, optical forces (e.g. photothermal or radiation pressure) can have a profound influence on micro-/nano-mechanical devices. Cavity opto-mechanics is a multi-disciplinary field that exploits these forces by enhancing light-matter interactions via feedback. We are studying chip-scale integrated cavity optomechanical structures. Our aim is to develop fully-integrated devices that can take advantage of optical forces. The devices will be all-optical in their actuation and readout, i.e. they do not require any electrical power on-chip.
One such integrated cavity optomechanical system consists of a silicon microbridge oscillator coupled to a Fabry-Perot resonator. The optical cavity consists of two silicon/air grating mirrors, one of which is fixed while the other is attached to the microbridge oscillator. Any oscillator motion will displace the grating and tune the cavity transmission. Optical forces that are generated by the high intensity of light inside the cavity result in a change in the oscillator dynamics (i.e. oscillation amplitude, linewidth and frequency).
We are interested in extending our optomechanics efforts to other architectures and material systems. In addition to silicon-based devices, silicon nitride, low-loss oxide, and compound semiconductor structures are of interest. We have demonstrated a linear cavity optomechanics architecture and are also interested in microring cavities as well as optical forces in the absence of cavities.