Alignment of a catadioptric infrared optical system

Abstract

In order to realize the high precision alignment of a catadioptric infrared optical system and improve the imaging quality of the system, a method of using visible light interferometer, infrared interferometer and articulated arm to align infrared optical system was proposed in this paper. First, the characteristics of the infrared optical system were introduced, and the alignment tolerances of each optical element were simulated and analyzed. Then, by aligning the R-C system of primary mirror assembly, the primary mirror assembly reference was extended to the mechanical mechanism, which provided the reference for subsequent precise alignment. The articulated arm was used to monitor the three-dimensional position of the lens assembly, in order to ensure the accuracy of the lens assembly initial alignment. Finally, the infrared interferometer was used to monitor the wavefront aberration of the system, and the relationship between the misalignment of the lens assembly and the zernike coefficient of the system was established, which could guide the alignment work, clear the direction of alignment, and finally realize the accurate alignment of the optical system. The experimental results indicated that the wavefront aberration values of the optical system were better than 1/15 λ (λ =3.39 μm), and each field amplitude transfer function(MTF) was better than 0.25, which met the requirements of imaging quality. It provided a feasible way for the catadioptric infrared optical system to be aligned, and also could be extended to the alignment of the remote sensors of similar structures space flight and aviation.