Paraxial propagation of astigmatic wavefronts in optical systems by an augmented stepalong method for vergences.

PURPOSE The propagation of astigmatic wavefronts through astigmatic optical systems is reconsidered in the wavefront perspective. METHODS The stepalong method for vergences, described by 2x2 matrices, is applied and augmented to produce off-axis information like the magnification. This so-called augmented stepalong method (ASAM) is derived by applying the paraxial propagation of astigmatic wavefronts to tilted wavefronts as well. RESULTS The features of the ASAM are discussed for a single surface, a thick lens, and a general system. CONCLUSIONS The ASAM provides all necessary information to describe a centered astigmatic optical system in paraxial approximation.