基于中红外QCL的痕量CO气体传感器

Trace CO gas sensor based on mid-infrared QCL

为了减少CO爆炸给国民经济造成的巨大损伤,提出了一种能够快速地监测环境空气中痕量CO的气体传感器。由于CO分子基频吸收谱带的吸收线强要比泛频带和组合频带的吸收线强高出2～3个数量级,选择激射中心波长为4.65μm中红外量子级联激光器（QCL）作为光源,同时再配合长光程Herriott气室提高了CO体积分数检测下限。同时,该传感器采用单光源双探测器差分光学结构,消除了电调制光源所带来的不稳定性。实验表明：该传感器CO体积分数检测下限为2×10-6,并且操作人员可以通过替换在不同波长下运行的中红外QCL来测量其它气体。

In order to decrease loss of national economy causing by carbon monoxide（ CO）,present a gas sensor for rapid monitoring of trace CO in air.Because CO absorption intensity in fundamental frequency absorption band is 2～ 3 orders of magnitude stronger than in double frequency and combination frequency band,so a quantum cascade laser（ QCL） with a center wavelength at 4.65 μm combing with long optical path herriott cell are utilized,which can enhance the CO low detection level.Meanwhile,single light source and two detectors differential optical structure is designed,which can eliminate instability caused by electrical modulated light source.The experimental results show that the CO volume fraction low detection level is 2 × 10- 6,and operator can substitute a QCL operating at a different wavelength to measure other gases.