Selective and switchable optical amplification with mechanical driven oscillators

We study optomechanically induced transparency (OMIT) in a compound system consisting of an optical cavity and an acoustic molecule, which features not only double OMIT peaks but also light advance. We find that by selectively driving one of the acoustic modes, OMIT peaks can be amplified either symmetrically or asymmetrically, accompanied by either significantly enhanced advance or a transition from advance to delay of the signal light. The sensitive impacts of the mechanical driving fields on the optical properties, including the signal transmission and its higher-order sidebands, are also revealed. Our results confirm that selective acoustic control of OMIT devices provides a versatile route to achieve multiband optical modulations, weak-signal sensing, and coherent communications of light.