中红外波段差分吸收检测气体池设计与实验

Design and experiment of gas cell for mid-infrared differential absorption detection

针对中红外波段差分吸收激光雷达探测性能标定的问题,设计并搭建了中红外波段差分吸收检测直通型气体池,以开展大气苯系物差分吸收光谱检测实验。以中红外带间级联激光器为光源,结合带间级联激光器的发射光束参数,设计了直通型气体池的结构参数和光学参数,测试了3187.0 nm和3235.3 nm波段的气体池透光特性和密封性能,并在此基础上,以苯为例开展了差分吸收激光雷达探测标定实验。结果表明,该气体池在测试波段的透光率大于85%,100 h的负气压减少约13 kPa,差分吸收光谱检测标定实验的相关系数为0.995,完全满足中红外波段差分吸收激光雷达的标定要求。

To address the problem of the detection performance calibration of differential absorption lidar in mid-infrared band,a straight-through gas cell for differential absorption detection in mid-infrared band was designed and constructed to carry out experiments on differential absorption spectroscopy detection of atmospheric benzene.The structural and optical parameters of the gas cell were designed by using a midinfrared interband cascade laser as the light source and combining the emission beam parameters of the interband cascade laser.Then the transmittance characteristics and sealing performance of the gas cell were tested at 3187.0 nm and 3235.3 nm wavelengths.Finally,differential absorption lidar detection calibration experiments were carried out using benzene as an example.The results showed that the light transmission rate of the gas cell in the test band was greater than 85%,the negative air pressure was reduced by about 13kPa after 100 h,and the correlation coefficient of the differential absorption spectroscopy detection calibration experiment was 0.995,indicating that the designed gas cell fully meets the calibration requirements of the mid infrared differential absorption lidar.