Micro-nano optical waveguide photo-thermal spectrum gas detection method and detection system

Abstract

The invention is suitable for the technical field of gas measurement, and provides a micro-nano optical waveguide photo-thermal spectrum gas detection method and detection system. The detection method provided by the invention comprises the following steps: pumping laser and detection laser are input into a micro-nano optical waveguide, a photothermal effect and accompanying heat conduction are generated between evanescent waves generated by the pumping laser and a to-be-detected substance in a gas medium, and the refractive indexes of the gas medium and the micro-nano optical waveguide are changed; the detection laser excites and generates a fundamental mode and a first high-order mode of the micro-nano optical waveguide, and the phase difference generated after the fundamental mode and the first high-order mode are transmitted in the micro-nano optical waveguide is detected, so that the concentration of the to-be-detected substance is obtained. The evanescent field with a large proportion can be obtained without harsh micro-nano optical waveguide preparation process conditions, the photo-thermal efficiency is high, the size is small, the cost is low, and the response speed is high. 本申请适用于气体测量技术领域，提供了一种微纳光波导光热光谱气体检测方法及检测系统。本申请所提供的检测方法，包括：将泵浦激光和探测激光输入微纳光波导，泵浦激光产生的倏逝波与气体介质中待测物质发生光热效应和伴随的热传导，改变气体介质和微纳光波导的折射率；探测激光激发生成微纳光波导的基模和第一高阶模，检测基模和第一高阶模在微纳光波导中传输后产生的相位差，获得待测物质的浓度。本申请无需苛刻的微纳光波导制备工艺条件即可获得大比例的倏逝场，光热效率高，尺寸小，成本低，响应速度快。