(Peer-Reviewed) Highly sensitive and fast response strain sensor based on evanescently coupled micro/nanofibers
Wen Yu 余文 ¹, Ni Yao ², Jing Pan 潘婧 ¹, Wei Fang 方伟 ¹, Xiong Li ³, Limin Tong 童利民 ¹, Lei Zhang 张磊 ¹ ²
¹ State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China
中国 杭州 浙江大学 光电科学与工程学院 现代光学仪器国家重点实验室
² Research Center for Intelligent Sensing, Zhejiang Lab, Hangzhou 311121, China
中国 杭州 之江实验室智 智能感知研究院
³ Tencent Robotics X Lab, Tencent Technology (Shenzhen) Co. Ltd, Shenzhen 518054, China
中国 深圳 腾讯科技（深圳）有限公司 腾讯Robotics X实验室
Flexible strain sensors play an important role in electronic skins, wearable medical devices, and advanced robots. Herein, a highly sensitive and fast response optical strain sensor with two evanescently coupled optical micro/nanofibers (MNFs) embedded in a polydimethylsiloxane (PDMS) film is proposed. The strain sensor exhibits a gauge factor as high as 64.5 for strain ≤ 0.5% and a strain resolution of 0.0012% which corresponds to elongation of 120 nm on a 1 cm long device.
As a proof-of-concept, highly sensitive fingertip pulse measurement is realized. The properties of fast temporal frequency response up to 30 kHz and a pressure sensitivity of 102 kPa−1 enable the sensor for sound detection. Such versatile sensor could be of great use in physiological signal monitoring, voice recognition and micro-displacement detection.