Higher-order aberration analysis in symmetry-free optical systems

Compared to the rotationally symmetric systems, the surface-decomposed aberrations of the symmetry-free system is harder for analysis, due to the invalidity of the conventional paraxial reference. To solve this problem, a novel higher-order aberration calculation method for symmetry-free systems is proposed based on the mixed ray-tracing method, which is proved as a good approximation of the full-order transverse aberration for generalized systems. Furthermore, the method is also applicable for intrinsic/induced aberration calculation, as well as the surface additive Zernike coefficient fitting. With various potential implementations, the method is considered a convenient and powerful tool for aberration analysis of off-axis systems.