GRAZING-INCIDENCE INTERFEROMETRY APPLIED TO THE MEASUREMENT OF CYLINDRICAL SURFACES

Usually, rough surfaces cannot be measured by interferometric methods because the wavefronts are disturbed by speckle noise. This problem ca n be overcome by an increase of the test wavelength. One way to increa se the effective wavelength is to use grazing incidence interferometry . We suggest an interferometer specifically adapted for the measuremen t of cylinders or tubes. Reference and object wavefront are generated using problem-specific computer-generated holograms as beamsplitters. The method can be extended to other geometries. We introduce the princ iple and show first experimental results.