Cold Optical Design of 10 THz Focal Plane Imaging System for Space Applications

In passive space exploration, the target signals are typically extremely weak and the detection system needs to achieve high sensitivity and low noise requirements. To satisfy these demands, cold optics has become indispensable. This method integrates optical components (such as lenses and mirrors) into cryogenic environments and combines them with cryogenic detectors to fulfill the detection needs. However, conventional optical design is constrained by the limited cooling capacity of spaceborne instruments. The research presents a cold optical model based on multi-reflection and optimizes the window size design according to this model. The cold optical experiment conducted in this research demonstrates a strong correlation between the predicted results and the experimental results, thereby confirming the effectiveness of the proposed model. The optimization of the window size is a critical factor in reducing thermal leakage and improving the overall performance of the system. From an optical perspective, the optical path delivers the desired signal; however, from a thermal perspective, it also introduces heat, imposing a thermal load on the cryogenic system. Engineering design must therefore strike a balance between these competing optical and thermal constraints. This research not only advances the field of cold optics but also provides a practical solution for the design of high sensitivity, low-noise detection systems in space applications. The proposed model and experimental validation offer a robust foundation for the development of more efficient and reliable cold optical systems, contributing to the advancement of space exploration technology. The method and results presented in this paper can serve as a reference for further research and development in the field of cold optical systems.