  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 transition and its high-order sidebands, are also
revealed. Our results confirm that selective acoustic control of OMIT devices
provides a versatile route to achieve multi-band optical modulations,
weak-signal sensing, and coherent communications of light.
