Ultrasensitive mass sensing using mode localization in coupled microcantilevers

Matthew Spletzer, Birck Nanotechnology Center and School of Mechanical Engineering, Purdue University
Arvind Raman, Birck Nanotechnology Center and School of Mechanical Engineering, Purdue University
Alexander Q. Wu, Birck Nanotechnology Center, School of Mechanical Engineering, Purdue University
Xianfan Xu, Birck Nanotechnology Center, School of Materials Engineering, Purdue University
R. Reifenberger, Birck Nanotechnology Center and Department of Physics, Purdue University

Abstract

We use Anderson or vibration localization in coupled microcantilevers as an extremely sensitive method to detect the added mass of a target analyte. We focus on the resonance frequencies and eigenstates of two nearly identical coupled gold-foil microcantilevers. Theoretical and experimental results indicate that the relative changes in the eigenstates due to the added mass can be orders of magnitude greater than the relative changes in resonance frequencies. Moreover this sensing paradigm possesses intrinsic common mode rejection characteristics thus providing an alternate way to achieve ultrasensitive mass detection under ambient conditions.