Abstract

Research subject. Trends and circuit designs of environmentally stabilized thermal-imaging optical systems developed and manufactured over the past few years at the Vavilov State Optical Institute are presented. Purpose. Current trends in the implemented Russian circuit designs for optical systems operating in the middle and long-wavelength infrared bands based on spherical components and the formulation of current research directions are reviewed. Method. The circuit designs developed in this study are based on using the algebraic method of designing optical systems by means of passive athermalization theory. This method is based on a special selection of materials for the optical and housing parts of the device and the calculation of beam paths at varying temperatures, followed by the calculation of image quality criteria. As a basic point in selecting possible materials for optical components, linear expansion coefficients, refraction index temperature variance coefficients, and their interrelation with structural parameters are adopted, with further calculation of the frequency-contrast response as the criterion of image quality most sensitive to varying conditions. Primary results. Primary trends are given for the development of circuit designs as a summary table of available options (according to optical characteristics and features of optical circuits) of the implemented optical systems at the Vavilov State Optical Institute over the past several years. Practical significance. In terms of developing optical systems for devices operating in the middle- and long-wavelength infrared bands, the technical solutions presented herein can act as an equivalent or a basic circuit for creating modernized optical systems in terms of optical performance, elements, and materials and the design solutions used in them.

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