Author Affiliations
Abstract
1 School of Physics, Harbin Institute of Technology, Harbin 150001, China
2 Photonics Research Institute, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hong Kong, China
3 National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150001, China
Laser absorption spectroscopy (LAS) has been widely used for unambiguous detection and accurate quantification of gas species in a diverse range of fields. However, up-to-date LAS-based gas sensors still face challenges in applications where gas concentrations change in a wide range, since it is extremely difficult to balance spectral analysis strategies for different optical thicknesses. Here we present laser vector spectroscopy that combines absorption spectroscopy with dispersion spectroscopy, simultaneously taking advantage of the former’s high sensitivity in the low-concentration region and the latter’s high linearity in the high-concentration region. In the proof-of-concept demonstration of acetylene measurement, it achieves a linear dynamic range of (), which surpasses all other state-of-the-art LAS techniques by more than an order of magnitude, with the capability of highly accurate quantification retained. The proposed laser spectroscopic method paves a novel way of developing large-dynamic-range gas sensors for environmental, medical, and industrial applications.
Photonics Research
2023, 11(10): 1687
1 哈尔滨工业大学物理学院, 黑龙江 哈尔滨 150001
2 哈尔滨工业大学可调谐激光技术国家级重点实验室, 黑龙江 哈尔滨 150001
激光吸收光谱 (LAS) 技术具有定量性好和操作便捷的优势, 已成为目前最为广泛使用的激光光谱气体检测技术, 但在许多实际应用中, 传统的 LAS 在光程精确测定、多点气体检测和大动态范围检测等方面的指标仍不能满足需求。介绍了一种基于光学调频连续波 (FMCW) 技术的气体光谱检测方法, 该方法将 FMCW 技术引入到 LAS 中, 在充分利用 FMCW 精确定位能力的同时, 挖掘光学 FMCW 信号中的吸收光谱信息。详细介绍了光学 FMCW 气体光谱检测技术的基本原理, 总结了本课题组采用该技术在多通池内气体吸收光谱和光程同步测量、多点式气体检测和大动态范围气体检测三个方面的最新研究进展, 并对下一步研究工作做了展望。
光谱学 吸收光谱 气体检测 调频连续波 多点式 大动态范围 spectroscopy absorption spectroscopy gas detection frequency-modulated continuous-wave multi-point large dynamic range
Author Affiliations
Abstract
1 School of Physics, Harbin Institute of Technology, Harbin 150001, China
2 National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150001, China
Laser absorption spectroscopy (LAS) has become the most widely used laser spectroscopic technique for gas detection due to its capability of accurate quantification and straightforward operation. However, since resolving weak absorption and averting over-absorption are always mutually exclusive, the dynamic range of the LAS-based gas sensor is limited and insufficient for many applications in fundamental study and industry. To overcome the limitation on the dynamic range, this article reports optical pathlength (OPL) multiplexed absorption spectroscopy using a gas cell having multiple internal reflections. It organically fuses together the transmission and reflection operation modes: the former directly uses the entire OPL of the gas cell, while the latter interrogates different internal short OPLs by optical interferometry, yielding -fold OPL variation. The achieved dynamic range is more than 6 orders of magnitude that surpasses other LAS techniques by 2–3 orders of magnitude. The proposed method promotes a novel way for the development of large-dynamic-range spectroscopic gas sensors for fundamental studies and industrial applications.
Photonics Research
2021, 9(2): 02000193
