Interferometric monitoring of the shape of concave parabolic and elliptical surfaces with large asphericity and slope

This paper discusses the features of using an interferometer to monitor the shape of concave parabolic and elliptical surfaces and presents results based on the properties of the anaberrational points of these surfaces. The interferometer brings about a single reflection of the rays from the test surface, and it therefore is suitable for testing aspheric surfaces that possess large deviations from a specified shape at the initial stage of their polishing. Such a situation is encountered when aspheric surfaces with large asphericity and slope are being shaped.