Optical system design and stray light suppression of catadioptric space camera

A lens group is used as an aberration correction group to solve the limited field of view angle and low imaging contrast at a large field of view in the coaxial two-mirror optical system. The lens group adopts reasonable optical power and pitch, it expands the field of view of two-reflection mirrors and improves imaging quality in the camera's full field of view. Taking an engineering application as an example, we design and develop an optical system with a 750 mm focal length, a field of view of 2ω=3.45°, an average transfer function better than 0.2 at 108 lp/mm, and an optimized design for its secondary mirror hood that suppresses stray light without a main mirror barrel hood. Simulation stray light was optimized by using TracePro software. The results show that the stray light Point Source Transmittance (PST) in the non-imaging field of view ranges from 10⁻³ to 10⁻⁶. The system meets the requirements for traditional ground target detection and imaging, the feasibility of a compact large-field refracting optical stray light suppression structure is verified, and a certain reference for the design and optimization of commercial coaxial refracting optical systems is provided.