High-sensitivity dynamic detection by tapping-mode nanomechanical sensing using an all-fiber microcantilever probe

In the quest for precise microscale material characterization, the development of high-performance sensors has become a pivotal research area. This study reports what we believe to be the first development of a dynamic microforce sensor that integrates a fiber-optic microcantilever probe operating in tapping-mode atomic force microscopy (AFM). By using femtosecond laser two-photon polymerization (TPP) nanolithography, the microstructure cantilever beam probes are prepared on the fiber end faces. Finite element analysis is performed to determine the dynamic mechanical properties of the optical fiber microcantilever, and the structure is optimized by parametric modeling. The optimized sensor shows a microforce sensitivity of 103 Hz/nm, a quality factor (Q) of 326.98, and a pN-level force detection limit (~17 pN). Owing to the simple structure and parallel probe configuration, the integrated sensor offers is highly promising in applications such as the quantitative analysis of viscoelastic properties of soft materials and biological samples.