Aspheric formtesting using multiple-wavelength approaches in combination with Sub-Nyquist-techniques

Aspheres with no rotational symmetry offer new perspectives for the development of high power laser optics. Confronted with the dynamic range of the manufacturing process recently opened by scientists in ultra-precision engineering, interferometric form testing is having to meet the challenge posed by complex mirror shapes with high local slopes andlor stepheights exceeding the range of unambiguity which conventional interferometry can handle. For this reason, special interferometric techniques such as Two-Wavelength- Interferometry, Sub-Nyquist- and Sub-Aperture- approaches are to be combined, to overcome the above mentioned problems. But even if the refined experimental setup is capable of resolving the interferometric fringe pattern, the question as to how the data collected should be interpreted, is extremely time-consuming. The use of ray-tracing software in experimental setups with chromatic aberrations or distortions is, therefore inevitable, building a theoretical background to distinguish between system and manufacturing errors