气体拉曼传感增强技术研究进展与趋势

不论是在科学研究，食品安全，医学检测，还是在安全事故预防等领域，对多组分混合气体进行快速、准确的定性定量分析已经成为一种迫切的需求 。拉曼光谱法是一种强大的气体传感方法，既能克服传统的非光谱法检测时间长、重复性差等弱点，又能弥补吸收光谱法无法直接测量同核双原子分子的缺点，同时还能使用单一频率的激光器对多组分混合气体进行定性和定量分析。但由于物质固有的弱拉曼效应，加之气体的拉曼效应一般远低于固体和液体，这极大地限制了拉曼光谱法在气体传感领域的应用。如何提高气体的散射强度是使气体拉曼传感技术得到更广泛应用的关键。目前最主要的气体拉曼传感增强技术包括腔增强技术和光纤增强技术。腔增强技术从提高与待测气体作用的激发光强度和作用路径来从源头上增强拉曼散射信号，包括多次反射腔增强、F-P腔增强、激光内腔增强。光纤增强则从提高球面散射光的收集效率来增强拉曼散射信号，使绝大部分拉曼散射光都能进入光谱探测器，包括镀银毛细管增强和空芯光纤增强。简要介绍了上述两种技术的的增强原理，汇总了研究进展以及应用现状，并讨论了它们各自的优势以及局限性，最后着眼于多组分痕量气体的检测，展望了气体拉曼传感技术未来的发展趋势。尽管目前基于吸收效应的光谱分析方法在气体检测领域占据主导地位，尤其是光声光谱法，但在不久的将来，气体拉曼传感技术有望在气体检测领域得到越来越广泛、越深入的应用。

Research Progress and Trend of Gas Raman Sensing Enhancement Technology

Whether in scientific research, food safety, medical testing, or in the fields of safety accident prevention, fast, accurate, qualitative and quantitative analysis of multi-component mixed gases has become an urgent need. Raman spectroscopy is a powerful gas sensing method. It can overcome the shortcomings of traditional non-spectroscopic methods, such as long detection time and poor repeatability, and it can also make up for the shortcoming of absorption spectroscopy that cannot directly measure homonuclear diatomic molecules. A single-frequency laser can be used for qualitative and quantitative analysis of multi-component mixed gases. However, due to the inherently weak Raman effect of matter, and the Raman effect of the gas is generally much lower than that of solid and liquid, this greatly limits the wider application of Raman spectroscopy in gas sensing. Improving the scattering intensity of gas is key to making gas Raman sensing technology more widely used. Currently, the most important gas Raman sensing enhancement technology includes cavity enhancement technology and optical fiber enhancement technology. Cavity enhancement technology enhances the Raman scattering signal from the source by increasing the intensity and path of the excitation light that interacts with the gas to be measured, including multiple pass cavity enhancement, F-P cavity enhancement, and laser cavity enhancement. Fiber enhancement, including silver-plated capillary tube enhancement and hollow fiber enhancement, enhances the Raman scattering signal by improving the collection efficiency of spherical scattered light so that most of the Raman scattered light can enter the spectral detector. This paper briefly introduces the enhancement principles of the above two technologies, summarizes the research progress and application status, and discusses their advantages and limitations. Finally, focusing on detecting multi-component trace gases, it looks forward to the future development trend of gas Raman sensing technology. Although the current spectrum analysis method based on the absorption effect dominates the field of gas detection, especially photoacoustic spectroscopy, shortly, gas Raman sensing technology is expected to be more extensive and in-depth in the field of gas detection.