FREQUENCY-RESPONSE OF CANTILEVER BEAMS IMMERSED IN VISCOUS FLUIDS WITH APPLICATIONS TO THE ATOMIC-FORCE MICROSCOPE

The vibrational characteristics of a cantilever beam are well known to strongly depend on the fluid in which the beam is immersed. In this p aper, we present a detailed theoretical analysis of the frequency resp onse of a cantilever beam, that is immersed in a viscous fluid and exc ited by an arbitrary driving force. Due to its practical importance in application to the atomic force microscope (AFM), we consider in deta il the special case of a cantilever beam that is excited by a thermal driving force. This will incorporate the presentation of explicit anal ytical formulae and numerical results, which will be of value to the u sers and designers of AFM cantilever beams. (C) 1998 American Instiute of Physics.