Specification of the figure and finish of EUV mirrors in terms of performance requirements. Revision 11/94

摘要

All manufacturing processes involve errors. In the case of bare and multilayer mirrors these unavoidable errors introduce near-field fluctuations in the reflected wavefront which propagate to the far field and degrade imaging performance. In order to specify manufacturing tolerances in terms of performance requirements we must know the connection between the two -- the finish-function relationship. This paper discusses the form of that relationship derived using elementary statistical diffraction theory. It tells us what statistical properties of the surface errors are relevant, it spells out the important role of the system parameters for EUV mirrors which is absent for conventional mirrors, and it leads to simple good-bad tests for mirror quality. These results are an extension of previous work in this area.