Christoph Kuebler

Fabrication of aspheric optics: process challenges arising from a wide range of customer demands and diversity of machine technologies

Different applications of aspheric optics and their related fabrication methods are firstly summarized and then discussed using Carl Zeiss examples. This is done in order to highlight the potential and challenges of fabricating aspheric optics. The need to stimulate new ideas for extending manufacturing capabilities, process improvements and new fabrication technologies will also be outlined.

Manufacturing, metrology, and assembly of the mirror system for the CDS-EM

Attention is given to the Coronal Diagnostic Spectrometer (CDS), one of the key instruments on the ESA-cornerstone mission SOHO, scheduled for launch in 1995. It is designed to study the solar corona in the EUV. The on-axis resolution of the system is specified to 2 arcsec half-energy-width, which sets very stringent limits on the figuring and alignment tolerances. From the mechanical measurements and the optical tests a system HEW of 3.3 arcsec at EUV wavelengths is predicted. The HEW at 633 nm, including diffraction, is 2.2 arcsec. A performance comparable to ROSAT was achieved on the CDS mirrors which, due to the much higher asphericity, are at least 20 times more difficult to manufacture. Assembly techniques have been developed which allowed the high accurate alignment of the type II telescope, which is much more sensitive to misalignments than type I telescopes of comparable focal length and required correcting mirror displacements of as little as 20 nm while ensuring sufficient stiffness during glueing.