Dual Optomechanical Cavities for All-Optical Actuation and Sensing of Mechanical Motion

Cavity optomechanics in the photonic devices enables a light-matter interaction in the chip-scale systems via the optical force driven mechanical motion. In this paper, a pump-probe scheme consisting of dual optomechanical cavities is proposed for the first time, where one optical cavity driven by a high input power act as a pump channel and the other one is used as a probe channel to detect the dynamical motion of mechanical resonator. Moreover, modulation of the optical force in the pump channel is achieved to observe the amplification of mechanical motions. As the light input of the pump channel increases, the dynamical displacement of the mechanical resonator is theoretically actuated to 4.8 nm
$/\!\sqrt {\text{Hz}} $
at the pump power of 0.75 mW. This all-optical amplification of mechanical motion based on the pump-probe scheme potentially paves the way for the development of optomechanical actuation and switch for the photonic integrated circuits.