通过外腔二极管激光器测量了甲烷位于1637.64～1637.85 nm(真空中)的2ν3带R9支的直接吸收谱,通过Voigt拟合计算出了每条线的吸收线强度,并与Margolis用傅里叶变换红外光谱仪测得的实验结果进行了比较,同时分析了偏差及产生的原因。实验和计算得出,在测得的八条吸收线中,最大偏差为3.9％,最小偏差为0.02％,除了线3和线4有较大偏差外,其他结果都在实验误差范围之内。所获得的数据可应用于光学遥测甲烷气体浓度。提供的方法也可应用到CO,CO2,NH3等其他气体的吸收线强度的测量中。

The direct absorption spectra of methane at 2ν3 band R9 manifold are measured within the wavelength range of 1637.64～1637.85 cm-1 (in vacuum) by ECDL (external-cavity diode laser), and the absorption line strength corresponding to those are worked out through Voigt fitting. In addition, these results are compared with those that have been done by Jack S. Margolis with Fourier transform infrared spectrometer and the error is analyzed. The experiment and the calculation represent that the biggest error is 3.9%; the smallest error is 0.02% for eight absorption lines. Except the line 3 and the line 4, the results are comprehensible. The acquired data are used to remote sensing of the concentration of methane. The methods of the measurement and the calculation here also can be applied to measure the absorption line strength of CO, CO2, NH3 etc..