Minimalist solid catadioptric telephoto and design method

To mitigate the alignment challenges of reflective telephoto systems and the extended optical paths of refractive systems, this paper proposes a mini employing a single cemented negative meniscus lens and outlines its design methodology. A theoretical model is developed based on Snell's law, which constrains the solution space; a fitness function is then constructed based on key design metrics, and the particle swarm optimization algorithm is employed to simultaneously optimize the lens parameters and the local reflective coating area, resulting in a viable initial configuration. Subsequently, an aspheric machined surface is introduced on the lens to correct residual aberrations. An alternative design consisting of two spherical lenses is also presented. The results demonstrate that the system achieves an 8° full field of view, an f-number of 4.5, a modulation transfer function exceeding 0.2 at 125 lp/mm, and near-diffraction-limited imaging in the visible band; tolerance analysis confirms its high robustness to manufacturing and alignment errors. The proposed design is compact, straightforward to manufacture, and cost-effective, providing a viable approach for miniaturized, high-performance telephoto imaging systems.