A nanonewton force sensor utilizing a U-shape tapered microfiber interferometer

Ling Chen, Bin Liu, Christopher Markwell, Juan Liu, Xing-Dao He, Zabih Ghassemlooy, Hamdi Torun, Yong-Qing Fu, Jinhui Yuan*, Qiang Liu, Gerald Farrell, Qiang Wu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Nanomechanical measurements, especially the detection of weak contact forces, play a vital role in many fields, such as material science, micromanipulation, mechanobiology, etc. However, it remains a challenging task to realize measurement of ultra-weak force levels as low as nanonewtons with a simple sensing configuration. In this work, a novel ultrasensitive all-fiber nanonewton force sensor structure based on single mode-tapered U-shape multimode-single mode fiber probe is proposed and experimentally demonstrated with a limit of detection of ~5.4 nN. The use of the sensor is demonstrated by force measurement on a human hair sample to determine the spring constant of the hair. The results agree well with measurements using an atomic force microscope for the spring constant of the hair. Compared with other force sensors based on optical fiber in the literature, the proposed all-fiber force sensor provides a significant advancement in the minimum detectable force possible, with the advantages of a simple configuration, ease of fabrication and low cost.
Original languageEnglish
JournalScience advances
Publication statusAccepted/In press - 12 Apr 2024

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