大气中二氧化硫(SO2)浓度很低,发出的荧光信号很弱,直接影响了SO2浓度的检测精度,并且传统荧光采集光路长,这阻碍了仪器的微型化发展。为提高荧光信号的采集效率以及仪器的检测精度,缩短传统光路,针对荧光随机性发散分布特征,利用ZEMAX软件进行痕量SO2荧光信号采集光路的设计,并与传统荧光采集光路进行对比仿真分析。仿真结果表明:优化后的荧光采集光路对荧光的采集效率约为22.6%,比传统荧光采集光路的采集效率高4倍,透镜组的像方主点到最佳采集点的距离减少了29.17%。优化后的光路有利于进一步实现已有大气痕量硫检测仪器的小型化改进与检测精度的提高。

The concentration of SO₂ gas in the atmosphere is very low, and therefore, the emitted fluorescent signal is weak, directly impacting the detection accuracy of SO₂ gas concentration. Owing to these issues, the optical path for traditional fluorescence collection is long, hindering the development of the miniaturization of instrument. To improve the collection efficiency of fluorescence signals and the detection accuracy of the instrument by shortening the traditional optical path, we used the ZEMAX software to design an optimized trace SO₂ fluorescence signal collection optical path for a random divergent distribution of fluorescence. We then compared the results from this path with those from the traditional fluorescence collection optical path. Simulation results show that the collection efficiency of optimized fluorescence collection optical path is approximately 22.6%, which is 4 times that of the traditional fluorescence collection optical path. The distance from the image-based main point of the lens group to the optimal collection point is reduced by 29.17%. The optimized optical path in this paper is beneficial for further improvements in the miniaturization and detection accuracy of the existing atmospheric trace sulfur detection instrument.