High-Resolution Micro Force Sensing Using a Microbubble Probe Resonator

High-resolution measurement of forces in micro/nano scale is essential to various applications. A novel miniature force sensor based on a whispering-gallery-mode (WGM) microbubble probe resonator (MPR) is presented in this work. The resonator consists of a thin-wall microbubble and a probe. The highest quality factor obtained is 1.10 × 10⁷. Predominately, the MPR achieves a promising force sensitivity of 19.7 pm/mN and a dynamic range of 0-36 mN. The MPR was used to measure the Young's modulus of a single mode optical fiber (SMF), and the result is coincided with the reported value. High force resolution and spatial resolution are achieved simultaneously. The sensor shows considerable performance and exhibits a potential in micro-force sensing and related applications such as material examination and Young's modulus measurement.