红外光学系统团簇污染对系统杂散辐射特性的影响

Influence of Particle Cluster Contamination on the Stray Light Radiation of Infrared Optical Systems

针对红外光学系统中光学元件表面粒子的污染问题,在考虑粒子叠加分布的基础上,提出了光学元件表面的非均匀团簇污染模型。以卡塞格伦式红外望远镜系统为例,用ASAP光学分析软件建模仿真,分析了该系统主镜在团簇污染后的杂散辐射特性及系统目标-背景对比度的变化,讨论了污染团簇位置对系统杂散辐射特性的影响。研究分析发现:光学元件镜面的团簇污染不仅会造成系统杂散辐射特性的变化,还会使系统的目标-背景对比度明显降低;并且,污染团簇在光学元件表面沉积的位置对系统杂散辐射的影响也会有所不同,镜面边缘附近团簇污染的影响比中心位置附近更明显。因此,在实际应用中,需要严格控制光学元件表面污染粒子的覆盖率,并及时、合理地清洗镜面。

Aiming at the particle contamination problem on infrared system's optical elements and considering the particle overlapping distribution,the cluster contaminants model was proposed.A Cassegrain telescope was taken as an example and the simulation model was built up by using the ASAP optical analysis software.The change of the system stray radiation and the contrast ratio between point objects and background were also simulated before and after the primary mirror was contaminated.The effects of different cluster contaminants position on system radiation property was discussed.The results indicated that the existences of the cluster not only alter the system's stray radiation properties,but also decrease the target-to-background contrast obviously.Further study showed that the position of contaminants cluster aggregation also effects more or less on the system stray light radiation and the contaminate of the mirror boundary has more effect than the center.Therefore,in practical applications,the factional area coverage of particles on optical components should be strictly controlled and the mirror should be cleaned reasonably in time.