Ultra high sensitivity in differential coupled micro/nano-resonator sensors

The resonance frequencies (eigenvalues) and amplitudes (eigenvectors) of coupled micro/nano-resonator arrays are used in sensors to measure applied physical perturbations such as mass. A higher sensitivity is obtained by measuring amplitude changes rather than frequency variations corresponding to identical perturbations. In this paper we present a new technique by measuring the difference of displacement amplitudes of two resonators in perturbed and unperturbed conditions that can increase the sensitivity by several orders of magnitude compared with frequency/amplitude measurements. Two coupled resonators implemented in SOI technology are modeled in Coventor to provide a proof of concept for the proposed idea. In the example coupled resonator, differential sensitivity is increased by 570 times for the first mode and by 170 times for the second mode compared with absolute sensitivity.