An Ultra-Sensitive Fiber Sensor for Micro-Newton Contact Force Detection Based on a Polymerized Hollow-Cylinder by One-Step Fabrication

An ultra-sensitive contact force sensor based on a polymerized hollow-cylinder lying on the end-face of single-mode fiber is proposed. The whole hollow-cylinder is polymerized in a single illumination with an annular beam, which is generated by a section of multimode fiber without resorting to any expensive instruments. It is fixed on the end-face of the fiber with UV-glue, working as a Fabry-Perot cavity. Owing to both the hollow structure and the low Young’s modulus of polymer, experimental results show the contact force sensitivity of the sensor reaches as high as 1.08 nm / <tex-math notation="LaTeX">μ N </tex-math> , and the detection resolution of the sensor is <tex-math notation="LaTeX">0.2~μ N </tex-math> .