Ultra-Sensitive Force Transduction in Weakly Coupled Resonators

This paper, for the first time, reports on a transducer configuration employing weakly coupled resonators demonstrating significant modal overlap. Existing multimode/mode-localized sensors conventionally operate in a regime where modal overlap is negligible; however, theoretically, the sensitivity of such systems significantly increases as the coupling strength between resonators is reduced, moving the system to a regime described by modal overlap. In this work, operation in the modal overlap regime is made possible with consequent benefits in input-referred resolution and stability. Specifically, a coupled resonator microsystem subject to electrostatic stiffness perturbations shows a sensitivity enhancement of 33682 and an input-referred amplitude ratio stability of 28.2ppb, demonstrating a ∼3x improvement in resolution compared to the resonant frequency shift technique.