为确定光学腔内高反射率镜片的反射率随波长的变化, 分别采用不同气体瑞利散射的差异性和已知浓度的吸收气体对同一对高反射率镜片的反射率随波长变化曲线进行标定.结果表明: 高反射率镜片在359~380 nm光谱区间内反射率曲线为0.99962~0.99990, 两种方法标定结果的相关系数达到0.998, 具有较高的一致性.用腔增强吸收光谱实验装置与商用氮氧化物分析仪同时对实际大气NO2进行测量, 验证了镜片反射率标定的准确性.

To calibrated the reflectivity of the mirrors in optical cavity, two methods of the calibration of mirror reflectivity, which are through a known concentration of an absorber and the difference of Rayleigh scattering, respectively, were introduced and compared. The reflectivity of the same pair of the highly reflecting mirrors were calibrated by these two methods. The reflectivity of the highly refecting mirrors are both 0.99962 to 0.99990 between the spectrum range of 359~380 nm, the linear correlation is 0.998, the results showed the good correlation. The atmospheric NO2 concentrations were simultaneously measured by the cavity enhanced absorption spectrocopy instrument and a commercial nitrogen-oxide analyzer to verify the accurate of calibration of the mirror reflectivity.