Asphere testing with a Fizeau interferometer based on a combined computer generated hologram

Fizeau interferometers with an additional diffractive optical element are frequently used for measuring spherical and aspherical surfaces. We present a new optical test method, where the Fizeau principle is now perfectly fulfilled, by generating reference and measuring wavefront on the last optical surface, carrying a diffractive optical element. This method has been experimentally examined by testing a reference f/0.68 spherical mirror and can be applied identically for testing aspheres. Recently, this method was applied to the qualification of aspherodiffractives and conformals successfully as well. On this poster, several advantages of this method are discussed and experimentally proved.