采用相对灵敏度为3.61×10-6cm-1Hz-1/2的QCL气体检测系统对室温下的甲醛气体进行了吸收光谱的测试, 采用F-P标准具对系统进行相对频率校准, 根据此波段甲烷的吸收谱线对甲醛吸收光谱进行绝对频率校准.当调谐QCL工作温度为-15℃～20℃, 以每5℃变化时, 采集并处理相应的频率调谐光谱.采用He, Ne, Kr, O2和CO2作为本波段的非吸收性缓冲气体作用于甲醛, 通过计算光谱数据得出1253.14392cm-1处甲醛的吸收线强度.给出了N2中的展宽光谱以及相应的光谱数据处理残差结果, 并对结果进行了分析.

The absorption spectra of H2CO were recorded at room temperature with a typical equivalent sensitivity of 3.61 × 10-6cm-1Hz-1/2 by utilizing a QCL based gas detection set-up. Relative frequency calibration based on F-P etalon and absolute frequency calibration based on CH4 spectrum are calculated and shown in this paper. Frequency tuning spectra are also measured and processed when changing the operation temperature from -15℃ to 20℃ with increment of 5℃. As nonabsorbent gases, He, Ne, Kr, O2 and CO2 were used to determine the line intensity of H2CO line centered at 1253.14392cm-1. Buffering spectrum in N2 and the corresponding statistical residuals were given to show broadening characteristics and the difference between the observed absorption data and the expected Voigt fit value with increasing the pressure of buffer gas.