A longitudinal-thermal actuation principle for mass detection using a resonant micro-cantilever in a fluid medium

We propose a new thermal actuation mechanical principle, which allows dynamic actuation in most media: air, water, etc. It is used to excite a cantilever, aiming to perform mass detection using resonance shifts, in place of the electrostatic or magnetic actuation that are normally used. It differs from existing thermal actuation configurations as the actuation acts on the base of the cantilever device, as opposed to the whole length of the device, separating cantilever and actuator. This allows much bigger freedom in optimizing separately the dimensions of cantilever and actuator. Optimizing the mass sensitivity of the device depends on the relative and absolute dimensions of the cantilever, by limiting fluid damping, displaced mass and cantilever mass. The ability to detect resonance shifts depends on the resonant amplitude, which can be optimized by varying the actuator dimensions and shape configuration, subject of investigation in the following paper. (C) 2004 Elsevier B.V. All rights reserved.