Hu Lien, Zheng Chuantao, Zhang Yu, Zheng Jie, Wang Yiding, Tittel Frank K
Opt Lett. 2020 Apr 1;45(7):1894-1897. doi: 10.1364/OL.388754.
To overcome the limitations of size, optical alignment, and integration into photonic circuits in previous light-induced thermoelastic spectroscopy (LITES) using free-space optics, a compact all-fiber LITES was proposed for gas sensing. A hollow-core photonic crystal fiber was employed as a waveguide and a microcapillary gas cell simultaneously. A single-mode fiber (SMF) tip was employed to guide light on the quartz tuning fork (QTF) surface. The distance between the SMF tip and the QTF, and the light excitation position on the QTF's surface were optimized experimentally. The detection performance of the all-fiber LITES was evaluated by detecting methane, and a normalized noise equivalent absorption coefficient of ${9.66} \times {{10}^{ - 9}}; {{\rm cm}^{ - 1}} \cdot {\rm W},{{\rm Hz}^{ - 1/2}}$9.66×10cm⋅WHz was realized at a 1 atm pressure and an environmental temperature of $ {\sim} 297;{\rm K}$∼297K. The combination of fiber sensing and LITES allows a class of LITES sensors with compact size and potential for long-distance and multi-point sensing.
为克服先前使用自由空间光学的光致热弹性光谱技术（LITES）在尺寸、光学对准以及集成到光子电路方面的局限性，提出了一种用于气体传感的紧凑型全光纤LITES。采用空心光子晶体光纤同时作为波导和微毛细管气室。使用单模光纤（SMF）尖端在石英音叉（QTF）表面引导光。通过实验优化了SMF尖端与QTF之间的距离以及QTF表面上的光激发位置。通过检测甲烷评估了全光纤LITES的检测性能，在1个大气压和环境温度约为297K的条件下，实现了归一化噪声等效吸收系数为9.66×10⁻⁹ cm⁻¹·W·Hz⁻¹/²。光纤传感与LITES的结合使得一类具有紧凑尺寸且具有长距离和多点传感潜力的LITES传感器成为可能。
