Li Xuejin

Analysis on Temperature Sensing Properties of Photonic Crystal Fiber Based on Liquid Filling

提出了一种基于在折射率引导型光子晶体光纤(PCF)中填充高折射率温度系数液体的新型折射率型光纤温度传感器.通过建立理论模型,设定入射波长和材料参数及完美匹配层边界条件,采用全矢量有限元法对六角形结构排列的折射率引导型光子晶体光纤的温度特性进行了分析.研究表明,在空气孔中填充液体乙醇,PCF模场分布随着温度变化明显,其有效折射率和限制损耗都随着温度升高而减小.相同的孔间距,占空比越大,输入波长越长,有效折射率和限制损耗受温度影响越大.当波长为1500 nm,占空比为0.7,温度从-20℃升至70℃时,限制损耗从3.5×102dB/m减小到22 dB/m.

Microbending optical fiber sensors and their applications

Microbending optical fiber sensors based on bend-induced loss in optical fiber have proved themselves useful for detecting environmental changes. Many different mechanical elements have been developed to perform the sensing, each with attributes suitable for a particular application. The key structures and principles of microbending optical fiber sensors for special applications are introduced in this paper. It mainly includes strain sensor, liquid lever and pressure sensor, differential force and displacement sensor, and temperature sensor specially.

Femtosecond Laser Ablated Polymer SERS Fiber Probe With Photoreduced Deposition of Silver Nanoparticles

In this paper, a surface-enhanced Raman scattering (SERS) spectral probe based on a polymethylmethacrylate (PMMA) polymer fiber is produced by femtosecond laser ablation and photoreduced deposition of silver nanoparticles. It shows that a surface grating structure enabled by femtosecond laser ablation could further improve the SERS signal by around four times larger than the ordinarily roughened structure. By varying femtosecond laser pulse energy and scan surface period in the fabrication process, the enhancement factor of the SERS signal is optimized with laser scan surface period of around 5 μm at 1.2 μJ femtosecond laser pulse energy for a PMMA fiber probe. In particular biochemical analysis, much softer SERS probes are preferred, and our polymer SERS fiber probe shows an alternative method for in situ measurement of the SERS signal and further fabrication of polymer SERS microchip.