Abstract: 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 13 kPa 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.

Key words: optical spectral detection, differential absorption technique, straight-through type gas cell; mid-infrared wavelength band, benzene concentration