光谱学与光谱分析, 2016, 36 (5): 1308, 网络出版: 2016-12-20
使用量子级联激光器和多通吸收光谱技术用于CO探测
Multi-Pass Absorption Spectroscopy for CO Detection Using a Quantum Cascaded Laser
一氧化碳 量子级联激光器 多反射气体吸收气室 空间滤波 Carbon Monoxide Quantum cascaded laser Multi-pass gas cell Spatial filtering
摘要
根据一氧化碳(CO)气体分子在4.7 μm处的基频吸收特性, 使用中心波长为4.75 μm的量子级联激光器(QCL)和多反射气体吸收气室(MGC)设计了一种新型CO传感器。 该仪器使用可在室温脉冲方式下工作并具有热电制冷功能的QCL, 通过对其温度和注入电流进行调节, 最终使得出射光波长定位在CO基频吸收带的一根强吸收线(2 103 cm-1)。 与此同时, 使用有效光程为16米的新型MGC(40 cm长, 800 ml采样容积)和液氮冷却碲镉汞中红外探测器, 有效提高了系统的响应灵敏度。 此外, 系统中配合使用了参考气室和空间滤波光学结构, 有效地改善了入射光束的质量, 降低了由光源的不稳定而产生的噪声, 进一步提高了系统的检测灵敏度。 在实验室条件下对不同浓度的CO气体进行多次重复检测, 结果显示, 该仪器工作稳定, 按信噪比为1计算, 可实现对一氧化碳气体的检测下限为5 μmol·mol-1。
Abstract
According to the fundamental absorption properties of Carbon Monoxide(CO) near 4.7 μm, a novel CO sensor was designed using a Quantum Cascaded Laser (QCL) whose central wavelength is 4.75 μm and Multi-pass Gas Cell (MGC). This sensor uses a QCL with the thermoelectrically cooled function and can work under pulse mode and room temperature, the exiting optical wavelength was located in a strong absorption line (2 103 cm-1)which is in the base band of CO through adjusting the injection current and temperature. Meanwhile, a novel MGC (40 cm long and 800 mL sampling volume) with 16 meters effective optical path length and mercury cadmium telluride mid-infrared detectors was used, thus effectively improved the sensitivity of this system. Additionally, a reference gas cell and a spatial filtering optical structure were occupied, resulting in effective improvement of the beam quality and reduction of the noise caused by the instability of QCL, the sensitivity of this system was improved furtherly. It indicated that the system works stably by means of multiple measurements to the carbon monoxide gas with different concentration, a detection limit of 5 μmol·mol-1 can be obtained when the signal-to-noise ratio equals 1.
李春光, 党敬民, 陈晨, 王一丁. 使用量子级联激光器和多通吸收光谱技术用于CO探测[J]. 光谱学与光谱分析, 2016, 36(5): 1308. LI Chun-guang, DANG Jing-min, CHEN Chen, WANG Yi-ding. Multi-Pass Absorption Spectroscopy for CO Detection Using a Quantum Cascaded Laser[J]. Spectroscopy and Spectral Analysis, 2016, 36(5): 1308.