An overview on induced color aberrations

Induced aberrations in general are higher-order aberrations caused by ray perturbations of lower order, picked up surface by surface in the preceding optical system. [1], [2] Therefore, induced aberration coefficients are to some extent depending on the cumulative preexisting aberrations in the system. In the case of color aberrations, induced influences are already observable in the paraxial regime, since even paraxial rays are affected by dispersion. Hence, in every optical system small perturbations in ray heights and ray angles for paraxial rays of different wavelengths are present. These ray perturbations generate induced color aberration effects of higher-order. Here, the different orders refer to the paraxial ray dependency on dispersion. The linear or 1st-order terms result in the well-known Seidel contributions of axial and lateral color, where any interaction of dispersion between different lenses is neglected. Starting at 2nd-order terms, induced color effects are present. [3], [4] In this contribution, at first an introduction on the basic idea of induced color aberration is given. Following this, a surface resolved analytical description for axial and lateral color, distinguishing between induced and intrinsic parts, will be derived and discussed on a descriptive design example. Here especially the reversibility of raytrace direction is considered.