单激光源谐波遥感探测甲烷研究

Research on the Remote Sensing of Methane with Harmonic Detection Employing Single Laser

提出了一种利用单一可调谐外腔二极管激光 (ECDL)及谐波探测技术对甲烷进行现场、实时遥感探测方案。通过理论推导计算出该方案在甲烷 2ν3 吸收带的R6支吸收线上理论最小可探测路径 积分浓度为 87× 10 -9。根据该方案建立了实验系统 ,实验结果验证了该方案的可行性并估算出实验最小可探测甲烷的路径 积分浓度为 4 2 0× 10 -9。

This article describes the design and testing of a laboratory prototype single diode laser system for remote detection of methane gas using harmonic detection. Harmonic signals are contained within radiation backscatter from topographic targets. A function of detected gas concentration depending on these harmonic signals is given by theoretical derivation. Base on it, minimum theoretical detection limit for methane is calculated to be about 87×10-9. The minimum measurable path-integrated concentration is estimated to be about 420×10-9 by experimentation with real situation in laboratory at 2ν3-band R(6) line of methane.