Aspheric optics at different quality levels and functional need

The design of optical systems gains profit from the application of aspheric elements: to correct for image aberrations, to reduce weight or system length or to cope with other functional needs like the number of reflections or the field size. Manufacturing, however, is suffering in practice from problems resulting from the reduced symmetry of the components as compared to spherical optics. Almost all large optical companies in the world are working on solving the problem of fabrication of accurate aspherical elements at reasonable cost. In this paper fabrication and metrology aspects of aspherical elements (mirrors and lenses) in the IR, visible, UV and EUV at Carl Zeiss and others companies will be discussed. The specifications achieved presently are ranging between some μm to nm for figure accuracy and 100 nm to 0.1 nm for microroughness.