Polarization Aberration of a Non-Rotationally Symmetric Optical System With Freeform Surfaces

Owing to the wide application of freeform surfaces in off-axis optical systems with large apertures, large fields of view, and long focus distances, the polarization effects caused by non-rotationally symmetrical surfaces have a significant impact on the system’s polarization imaging quality and measurement accuracy. In this study, considering the problem of the aforementioned polarization effects, a polarization aberration analysis method based on the Jones notation using the fringe Zernike polynomials freeform surface is proposed. A full-field polarization aberration analysis model of a non-rotationally symmetric reflection optical system with a freeform surface is constructed. The effect of freeform surfaces on the distribution characteristics of the proposed model is demonstrated. Through the full-field polarization ray tracing of the field-of-view off-axis optical system, three kinds of polarization aberrations, comprising phase aberration, retardance, and diattenuation are obtained, after the introduction of the Zernike polynomial freeform surface. Finally, a full-field polarization aberration analysis is carried out for a wide-field off-axis three-reflection optical system with freeform surfaces. The results show that the phase aberration of a non-rotationally symmetric optical system with freeform surfaces is directly related to the freeform surface shape. The full-field of view distribution of the retardance and diattenuation caused by the free-form surface is 52.5% of the overall retardance and diattenuation distribution of the system. The proposed method will be of great significance for improving the accuracy of systems in deep-space telescopes and lithography objectives.