ENCASED CANTILEVERS FOR LOW-NOISE FORCE AND MASS SENSING IN LIQUIDS

Abstract

Viscous damping severely limits the performance of resonator based sensing in liquids. We present encased cantilevers that overcome this limitation with a transparent and hydrophobic encasement built around the resonator. Only a few micrometers of the cantilever probe protrude from the encasement and water does not enter the encasement. This maintains high Q-factors and reduces the thermo-mechanical noise levels by over one order of magnitude and reaches minimal detectable forces of 12 fN/•Hz in liquids. These probes expand the frontiers of cantilever based sensing. We discuss their design and fabrication with special focus on squeeze film damping and demonstrate their successful application..