基于量子级联激光器和长光程气室的甲烷传感器

发布时间：2018-09-17 08:26

【摘要】：根据中红外光谱吸收原理,利用甲烷(CH_4)气体分子在7.5μm处的基频吸收特性,设计了一种基于量子级联激光器(QCL)和新型多反射长光程气体吸收气室(MPC)的甲烷气体传感器。该仪器使用了可进行热电冷却、工作在脉冲方式下、中心波长为7.5μm的QCL,通过在室温条件下调节其注入电流(500mA~1.6A调节范围),其出射光波长可以扫过CH_4(1 332.8cm~(-1))气体吸收线。同时使用了一种紧凑型MPC(40cm长,800mL采样容积),使得系统有效总光程达到16m。此外,系统中使用了参考气室,并加入了空间滤波光学结构以满足MPC对入射光束的要求,配合差分吸收光谱检测原理,有效地改善了光束质量,降低了由光源波动引起的噪声,提高了仪器的检测灵敏度。通过对不同浓度的甲烷气体进行多次检测,该仪器的稳定性能良好,按信噪比为1计算,可实现对甲烷气体的检测下限为1μmol·mol~(-1)。
[Abstract]:Based on the principle of mid-infrared absorption and the fundamental frequency absorption of methane (CH_4) molecules at 7.5 渭 m, a methane gas sensor based on a quantum cascade laser (QCL) and a new multi-reflection long-path gas absorption chamber (MPC) is designed. The instrument uses thermoelectric cooling, and works in pulse mode. QCL, with a central wavelength of 7.5 渭 m adjusts its injection current (500mA~1.6A range) at room temperature, and its output wavelength can sweep over the CH_4 (1 332.8 cm ~ (-1) gas absorption line. At the same time, a compact MPC (40cm length 800 mL sampling volume) is used to make the total effective optical path of the system up to 16 m. In addition, the reference chamber is used in the system, and the spatial filter optical structure is added to meet the requirement of MPC for incident beam. With the principle of differential absorption spectroscopy, the beam quality is effectively improved and the noise caused by the fluctuation of the light source is reduced. The sensitivity of the instrument is improved. The stability of the instrument is good, and the detection limit of methane gas is 1 渭 mol mol~ (-1) according to the signal to noise ratio (SNR) of 1.
【作者单位】：吉林大学集成光电子学国家重点联合实验室电子科学与工程学院;吉林农业大学信息技术学院;吉林大学国家地球物理探测仪器工程技术研究中心仪器科学与电气工程学院;
【基金】：国家科技支撑计划项目(2013BAK06B04) 国家自然科学基金项目(61307124),国家自然科学基金项目(61403160) 国家(863)计划项目(2007AA06Z112) 吉林省科技发展计划项目(20120707) 长春市科技发展计划项目(11GH01) 第55批中国博士后面上基金项目(2014M551194) 吉林省科技厅项目(20150414052GH,20140520118JH)资助
【分类号】：TP212;TN248;O657.3

【相似文献】