Three-flat test solutions based on simple mirror symmetry

Ulf Griesmann
2006 Applied Optics  
In interferometric surface and wavefront metrology, three-flat tests are the archetypes of measurement procedures to separate errors in the interferometer reference wavefront from errors due to the test part surface, so-called absolute tests. What is believed to be a new class of solutions of the three-flat problem for circular flats is described in terms of functions that are symmetric or antisymmetric with respect to reflections at a single line passing through the center of the flat
more » ... f the flat surfaces. The new solutions are simpler and easier to calculate than the known solutions based on twofold mirror symmetry or rotation symmetry. Strategies for effective azimuthal averaging and a method for determining the averaging error are also discussed. OCIS codes: 120.3180, 120.3940, 220.4840. U. Griesmann (ulf.griesmann@osa.org) is with the Manufacturing Engineering
doi:10.1364/ao.45.005856 pmid:16926872 fatcat:2i3xr55ih5cave3ewolsggj36y