Design method of off-axis reflective aperture-divided optical system

The aperture-divided optical system is a significant imaging technique that enables real-time imaging with multiple channels. However, an increasing demand for multi-channel optics presents a substantial challenge for current refractive optical systems with complex structures and a narrow wavelength band. In this paper, we propose a modified design method that combines the strengths of an off-axis reflective system and an aperture-divided optical system to achieve high levels of integration and simplified structure. A design concept of integrated optical layout and local detail optimization is proposed here. We present an analysis showing how local sub-channels’ distribution affects the imaging characteristics. An integrated optical system, including a relay group constructed based on the Wassermann–Wolf differential equations and a telescope objective, is built first. The sub-aperture system utilizing distinct local surface regions is gradually established with a close connection. To demonstrate the feasibility and efficiency of the method, an integrated system with an F-number of 1.6 and an entrance pupil of 130 mm is presented with its design strategies. The aperture-divided system illustrates well imaging performance close to the diffraction limit in 3–5 µm at 33 lp/mm. The design strategy we have proposed not only has a broad application to multi-channel imaging but also provides valuable insight into to our knowledge, the new imaging technology.