Liu Yang, Li Xiaowei, Huang Ji, Wang Zhipeng, Zhao Xiaoming, Zhao Bingquan, Jiang Lan
Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, P. R. China.
National Institute of Metrology, Beijing 100029, P. R. China.
ACS Appl Mater Interfaces. 2022 Apr 13;14(14):16911-16919. doi: 10.1021/acsami.2c01735. Epub 2022 Apr 4.
As one of the important diffractive optical elements, the submicron gratings on flexible substrates can actively and precisely control the dispersion and steering characteristics of beams and have been widely applied in deformation detection technologies. Herein, we propose a spatially modulated femtosecond laser-assisted molding technology for efficiently fabricating high-uniformity large-area submicron gratings with tunable periods on flexible substrates. The technology first uses a cylindrically focused femtosecond laser-assisted chemical etching method to form a regular submicron grating on silicon; subsequently, the structure is cast with polydimethylsiloxane, a useful flexible substrate with a small Young's modulus, and cured to obtain a high-uniformity large-area submicron grating with a tunable period. The grating exhibits high mechanical stability and sensitivity and favorable optical properties. In the present study, as the deformation of the grating increased from 0 to 10%, the diffraction angle changed by 6.5°. Under illumination by a broad-band white-light source, distinguishable multicolor diffraction patterns were clearly observed. Drawing on this characteristic, we fabricated a deformation sensor. The grating fabricated by using the proposed technology also has potential applications in optical sensors and soft robots.
作为重要的衍射光学元件之一，柔性衬底上的亚微米光栅能够主动且精确地控制光束的色散和转向特性，并已在变形检测技术中得到广泛应用。在此，我们提出一种空间调制飞秒激光辅助成型技术，用于在柔性衬底上高效制备具有可调周期的高均匀性大面积亚微米光栅。该技术首先采用柱面聚焦飞秒激光辅助化学蚀刻方法在硅上形成规则的亚微米光栅；随后，用聚二甲基硅氧烷（一种杨氏模量较小的有用柔性衬底）对该结构进行浇铸，并固化以获得具有可调周期的高均匀性大面积亚微米光栅。该光栅具有高机械稳定性和灵敏度以及良好的光学性能。在本研究中，随着光栅变形从0增加到10%，衍射角变化了6.5°。在宽带白光源照射下，清晰地观察到了可区分的多色衍射图案。利用这一特性，我们制作了一个变形传感器。采用所提出的技术制造的光栅在光学传感器和软机器人方面也具有潜在应用。
