基于中红外激光吸收光谱技术的微量乙炔检测研究  

Trace acetylene detection based on mid-infrared laser absorption spectroscopy technology

作　　者：刘立富 冯雨轩 陈东 晏明月 吴强 LIU Lifu;FENG Yuxuan;CHEN Dong;YAN Mingyue;WU Qiang(Industrial Division of Hangzhou Chunlai Technology Co.,Ltd.,Hangzhou 310052,China)

机构地区：[1]杭州春来科技有限公司工业事业部,浙江杭州310052

出　　处：《量子电子学报》2021年第5期648-660,共13页Chinese Journal of Quantum Electronics

摘　　要：基于可调谐半导体中红外激光吸收光谱技术与长光程多次反射技术的有机结合,利用乙炔(C2H2)气体位于中红外波段3025.7 nm附近的吸收谱线,实现了nmol/mol级微量C_(2)H_(2)气体的快速实时检测。通过DDS芯片AD9958产生高频正弦波与三角波信号叠加,经恒流电路实现对带间级联激光器的稳定驱动,采用HgCdTe光电检测器接收中红外激光,通过集成锁相放大器提取目标信号。基于White型多次反射与平面反射的组合设计了一款长光程吸收池,测量光程达到19.2 m,进一步降低了C_(2)H_(2)检出限。在实验室对0∼1000 nmol/mol微量C2H2进行了初步测试,结果表明线性误差不超过±1%F.S.,检出限达到0.29 nmol/mol,表明该方法具有测量准确性高、测量不受背景气体交叉干扰和使用方便等优势。Based on the combination of tunable diode mid-infrared laser absorption spectroscopy technology and long optical path multiple-reflection technology,the fast and real-time detection of trace acetylene in nmol/mol level is studied by using C_(2)H_(2) gas absorption spectrum near 3025.7 nm in midinfrared region.The driving current of the interband cascade laser is modulated by the superimposition of the high frequency sine wave generated by DDS AD9958 and triangle wave signal,and then the stable driving of laser is realized through constant current circuit.HgCdTe photodetector is used to receive midinfrared laser,and target signal is extracted by integrated lock-in amplifier.A long optical path absorption cell is designed based on the combination of White multiple-reflection and plane reflection,and its measured optical path reaches 19.2 m,which further reduces the detection limit of C_(2)H_(2).In laboratory,trace C_(2)H_(2) gas sample is measured with the concentration ranging from 0 to 1000 nmol/mol.It shows that the linear error is less than±1%F.S.,and the detection limit is 0.29 nmol/mol,which indicates that the method has the advantages of high accuracy,no cross interference from background gas and convenient use.

关 键 词：光谱学 中红外激光 多次反射 C_(2)H_(2)检测 

分 类 号：O433.4[机械工程—光学工程]