Exponential tuning of the coupling constant of coupled microcantilevers by modifying their separation

Vibration localization in coupled nanomechanical resonators has emerged as a promising concept for ultrasensitive mass sensing. It possesses intrinsic common mode rejection and the mass sensitivity can be enhanced with no need of extreme miniaturization of the devices. In this work, we have experimentally studied the role of the separation between cantilevers that are elastically coupled by an overhang. The results show that the coupling constant exponentially decays with the separation. In consistency with the theoretical expectations, the mass sensitivity is inversely proportional to the coupling constant. Finite element simulations show that the coupling constant can be exponentially reduced by increasing the ratio of the cantilever separation to the overhang length.