基于空芯光纤增强拉曼光谱气体探测方法研究

Raman Signal Enhancement for Gas Detection Using a Hollow Core Optical Fiber

拉曼光谱技术具有多组分同时探测、分析周期短和非接触等特点,被应用于多个领域,但是由于较低的探测灵敏度,限制了拉曼光谱技术的发展。针对提高拉曼光谱技术对气体探测灵敏度问题,本文设计并搭建了一套基于空芯光纤气体拉曼光谱增强系统,开展了空芯光纤拉曼光谱系统和后向散射拉曼光谱实验系统对比实验研究。实验结果表明,空芯光纤对信号、背景和噪声都具有放大效果,以空气中氮气和氧气为探测物质,与后向拉曼光谱信号相比,在相同探测时间情况下,信号强度增强60倍以上,信噪比增强约6倍;在相同探测强度情况下,探测时间仅为后向散射的1/60,噪声为后向散射拉曼系统的1/2。

Raman spectroscopy has been widely used for gas detection due to the advantages of simultaneous multiple species recognition,rapid analysis,and no sample preparation,etc.Low sensitivity is still a great limitation for Raman application.In this work a Raman system based on a hollow core optical fiber（HCOF）was built and the detection sensitivity for the gas was significantly improved.Also a comparison was carried out between the HCOF Raman system and back-scattering Raman system.The obtained results indicated that the HCOF Raman system could well enhance the signal while also for the background and noise.Using HCOF system,60 folds signal enhancement was achieved with SNR improvement of 6times for the N2 and O_2in air when comparing to the back-scattering system.While for the same signal intensity,with HCOF system the exposure time was well shortened to 1/60 and the noise was decreased to 1/2than the back-scattering system.