A strongly coupled Λ-type micromechanical system

摘要

We study a classical A-type three-level system based on three high-Q micromechanical beam resonators embedded in a gradient electric field. By modulating the strength of the field at the difference frequency between adjacent beam modes, we realize strong dynamic two-mode coupling, via the dielectric force. Driving adjacent pairs simultaneously, we observe the formation of a purely mechanical "dark" state and an all-phononic analog of coherent population trapping-signatures of strong three-mode coupling. The A-type micromechanical system is a natural extension of previously demonstrated "two-level" micromechanical systems and adds to the toolbox for engineering of all-phononic micromechanical circuits and arrays.