АНАЛИЗ ПАРАЗИТНОГО ИЗЛУЧЕНИЯ В КАТАДИОПТРИЧЕСКИХ ОПТИЧЕСКИХ СИСТЕМАХ

Abstract

This article discusses methods for calculating and analyzing the amount of straylight hiting the detector of a catadioptric optical system designed for remote sensing of the Earth. With increasing demands on the accuracy and resolution of observations with the trend towards mimiaturization of space technology, restrictions on the number and size of starylight-blocking elements are increasing, despite the fact that even a small fraction of straylight can greatly distort the useful signal, impairing contrast and reducing the signal-to-noise ratio. In this paper, the task is to develop and test an integrated approach for calculating the amount of starylight entering the detector and developing methods for its minimization.

Ansys Zemax OpticStudio software, which operates in the non-sequential mode of ray propagation modeling, is used as a modeling tool. This approach makes it possible to take into account multiple reflections and scattering inside the optomechanical structure of the telescope, including both optical and mechanical components. It is shown that the external and internal baffles, as well as special anti-reflective coatings for lenses, make a decisive contribution to reducing the number of parasitic rays reaching the detector. The article presents the results of test calculations, compares configuration options (with and without different baffles, in combination or without combination with coating), it estimates the total power of the straylight and the maximum illumination of the detector.

The practical importance of the work lies in the fact that the detailed calculated indicators allow designers to identify sources of parasitic radiation (glare, re-reflection, scattering) and make changes to the system design (diaphragms, lenses, coatings) to minimize it, thereby preventing image quality degradation., Minimizing parasitic radiation increases the contrast and accuracy of data, providing clear and informative images, which is necessary in optical payloads of remote sensing satellites for reliable analysis of the state of the environment, agriculture, and other remote sensing tasks.