RESUMEN
In this paper, a novel, to the best of our knowledge, method is proposed to design a freeform off-axis three-mirror reflective imaging system. A special algorithm is demonstrated to calculate the data points on the unknown freeform surface using the rays from the pupil of the center field. Then the three-dimensional shape of the freeform surface is solved by these characteristic points, which serves as a good starting point for further optimization. The benefit of this design method is demonstrated by designing a freeform off-axis three mirror imaging system with high performance. The final system operates at F/2 with an entrance pupil diameter of 400 mm and a field of view of 2.4∘×2.4∘. The modulation transfer function (MTF) value of the system reaches 0.6 at 100 lp/mm or higher at all fields of view.
RESUMEN
This paper introduces an optimized method for zonal wavefront reconstruction utilizing Fan's model, specifically tailored to enhance the frequency response. Analysis of the system frequency response demonstrates a 27% increase in bandwidth compared to the Southwell model. Examination of reconstruction errors at various frequency points reveals consistently smaller values when compared to the Southwell model. Validation through numerical simulations and real experiments underscores the superior performance of the proposed reconstructor, particularly noticeable at higher response levels within the mid- and high-frequency domains.