Design of a three-channel common-aperture miniaturized optical system based on the Ritchey-Chretien (RC) telescope

To meet the demands for miniaturization and high performance in multi-channel optical systems for applications such as atmospheric environment monitoring, climate change research, and space target identification and tracking, this paper presents a compact three-channel optical system based on a common-aperture design. The system includes a long-wave infrared (LWIR) channel, a visible-star sensor channel, and a laser ranging channel, which are used for space target detection, stellar point target imaging observation, and high-precision target ranging, respectively. Through analyzing the observational requirements for space targets at a long distance of 50 km, the paper determines the overall specifications for the optical system. During the design process, a cassegrain structure and a combination of multi-material lenses are employed to mitigate chromatic aberration. Additionally, optical design software is used to optimize the system, achieving a compact layout and high imaging quality. The results show that the overall system achieves balanced performance across multiple channels. The infrared channel has an F-number (F^#) of 2, with modulation transfer function (MTF) values above 0.2 at the Nyquist frequency, approaching the diffraction limit. The infrared system achieves 100 % cold stop efficiency, ensuring efficient energy concentration and fully meeting design requirements. The visible channel maintains stable spot quality, with maximum distortion better than 0.024 % and accurate centroid positioning. Meanwhile, the laser ranging receiver channel demonstrates precise distance measurement capability. Finally, a tolerance analysis was conducted for each optical channel to verify the theoretical accuracy and manufacturability of the system. This optical system scheme effectively reduces the volume and weight of space optical payloads, providing a new solution for the practical deployment of multi-channel optical systems in complex application scenarios and demonstrating significant application value.