Analysis of the resonance characteristics of a cantilever vibrated photothermally in a liquid

Abstract
The resonance characteristics of stainless‐steel cantilevers vibrated photothermally in a liquid have been investigated using an optical detection system. Resonance frequencies of vibrating cantilevers in liquids are lower than those in air as a result of the action of reaction forces in the liquid. It is shown that experimental values of the resonance frequencies for several types of cantilevers in water agree well with those calculated. The half power width at resonance broadens with increasing viscosity of the liquid. The possibility for using this photothermal vibration method as an optical sensing system for the density or viscosity of liquids is described.