Real-time stochastic response analysis as a tool for monitoring cantilever mechanical properties ☆

Microcantilever-based sensors are very promising devices for biochemical applications. They are usually operated in two modes. In the first one, a microcantilever static bending induced by the surface stress is observed. In the second mode, resonant frequency shift caused by mass loading is measured. The second mode requires an external force to excite cantilever vibrations. There is a possibility to use a stochastic excitation signal to estimate frequency shift as well as other interesting mechanical properties, such as effective spring constant or damping. Cantilever thermal self-vibrations or artificially generated white noise are very convenient examples of such a stochastic excitation signal.