Manipulation of fast and slow light propagation by photonic-molecule optomechanics.

We demonstrate theoretically coherent optical propagation in a composite photonic-molecule-cavity optomechanical system consisting of two whispering-gallery microcavities in which one of the optical cavities is optomechanical with high cavity dissipation and the other is an auxiliary with a high quality factor. Optomechanically induced transparency and its related propagation properties such as fast and slow light effects are investigated based on the hybrid system for suitable parametric regimes. By controlling the coupling strength J between the two cavities, which is determined by their distance and the decay rate ratio δ of the two cavities, tunable and controllable fast-to-slow light propagation (or vice versa) can be achieved. Our study may provide a further insight of the composite photonic-molecule optomechanical systems and may open up promising on-chip applications in quantum information processing. [ABSTRACT FROM AUTHOR]