Ultrasensitive skin-like wearable optical sensors based on glass micro/nanofibers
Lei Zhang, Jing Pan, Zhang Zhang, Hao Wu, Ni Yao, Cai Dawei, Yingxin Xu, Jin Zhang, Sun Guofei, Liqiang Wang, Weidong Geng, Wenguang Jin, Wei Fang, Dawei Di, Tong Limin
Abstract
Electronic skin, a class of wearable electronic sensors that mimic the functionalities of human skin, has made remarkable success in applications including health monitoring, human-machine interaction and electronic-biological interfaces. While electronic skin continues to achieve higher sensitivity and faster response, its ultimate performance is fundamentally limited by the nature of low-frequency AC currents. Herein, highly sensitive skin-like wearable optical sensors are demonstrated by embedding glass micro/nanofibers (MNFs) in thin layers of polydimethylsiloxane (PDMS). Enabled by the transition from guided modes into radiation modes of the waveguiding MNFs upon external stimuli, the skin-like optical sensors show ultrahigh sensitivity (1870 kPa<sup>-1</sup>), low detection limit (7 mPa) and fast response (10 μs) for pressure sensing, significantly exceeding the performance metrics of state-of-the-art electronic skins. Electromagnetic interference (EMI)-free detection of high-frequency vibrations, wrist pulse and human voice are realized. Moreover, a five-sensor optical data glove and a 2×2-MNF tactile sensor are demonstrated. These initial results pave the way toward a new category of optical devices ranging from ultrasensitive wearable sensors to optical skins.