Xie Fei, Liang Lili, Yang Kang, Jia Sumei, Wang Zhihui, Li Li, Wang Wei, Wang Miaomiao, Li Guoyu, Li Yan
Hebei Key Laboratory of Optical Fiber Biosensing and Communication Devices, Institute of Information Technology, Handan University, Handan 056005, China.
Materials (Basel). 2022 Nov 3;15(21):7753. doi: 10.3390/ma15217753.
Through the merits of the arbitrary three-dimensional (3D) fabrication ability and nanoscale resolution of two-photon polymerization, we demonstrated a fully encircled polymerized microfiber Bragg grating using 3D femtosecond laser nanofabrication. In order to generate strong enough polymer Bragg grating units around the microfiber surface, and to possess a possible smaller unit pitch and structure size, the composition of photoresist and grating dimensions were both experimentally optimized. A fast-curing, high-adhesion, great-heat-resistant acrylate monomer EQ4PETA was chosen as the cross-linking element, and a high-efficiency photoinitiator DETC was used. Along the tapered microfiber with a diameter of 2 microns, dozens of grating units of 300 nm thickness were successively fabricated. The resonance wavelength was approximately 1420 nm, with a unit pitch of 1 μm, slightly different with varying unit pitches. The refractive index sensitivity reached up to ~440 nm/RIU, which is much higher than other microfiber grating sensors. We also measured the temperature and strain sensitivity of this fully encircled microfiber Bragg grating, and this was estimated at 88 pm/°C and 6.3 pm/µε. It is foreseeable that with the continuous progress of fabrication technology, more highly integrated functional optical devices will emerge in the future.
通过双光子聚合的任意三维（3D）制造能力和纳米级分辨率的优势，我们利用3D飞秒激光纳米制造技术展示了一种完全环绕的聚合微光纤布拉格光栅。为了在微光纤表面周围产生足够强的聚合物布拉格光栅单元，并拥有可能更小的单元间距和结构尺寸，对光刻胶的成分和光栅尺寸都进行了实验优化。选择了一种快速固化、高附着力、高耐热性的丙烯酸酯单体EQ4PETA作为交联元素，并使用了一种高效光引发剂DETC。沿着直径为2微米的锥形微光纤，相继制造了数十个厚度为300纳米的光栅单元。共振波长约为1420纳米，单元间距为1微米，不同单元间距略有差异。折射率灵敏度高达约440纳米/RIU，远高于其他微光纤光栅传感器。我们还测量了这种完全环绕的微光纤布拉格光栅的温度和应变灵敏度，估计分别为88皮米/°C和6.3皮米/με。可以预见，随着制造技术的不断进步，未来将出现更多高度集成的功能性光学器件。
