Null-screen testing of fast convex aspheric surfaces.
A method for null-testing fast convex aspheric optical surfaces is presented. The method consists of using a cylindrical screen with a set of lines drawn on it in such a way that its image, which is formed by reflection on a perfect surface, yields a perfect square grid. Departures from this geometry are due to imperfections of the surface, allowing one to know if the surface is close to the design shape. Tests conducted with a full hemisphere and with the parabolic surface of a lens show the feasibility of the method. Numerical simulations show that it is possible to detect surface departures as small as 5 microm.
Díaz-Uribe
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Laboratorio de Optica Applicada, Centro de Instrumentos, Universidad Nacional Autónoma de México, Apartado Postal 70-186, México 04510, Distrito Federal México. rufino@aleph.cinstrum.unam.mx
Campos-García
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