Abstract: The invention in one aspect involves a method for repairing an optical system. The optical system includes at least one optical element which comprises, in turn, a substrate having a principal surface, and a multilayer coating overlying the principal surface. The substrate comprises a first material, and the multilayer coating comprises plural second and at least third material layers in alternation. The method includes the steps of removing the multilayer coating from the substrate, and redepositing a new multilayer coating on the substrate. The old multilayer coating is removed in a single etching step while preserving the quality of the principal surface to such an extent that the peak reflectivity of the new multilayer coating is at least 80% the reflectivity of the old multilayer coating.

Abstract: In one aspect, the invention involves an optical element in an x-ray imaging system. The element comprises a substrate overlain by a multilayer coating. The multilayer coating comprises plural first and at least second material layers in alternation. This coating is soluble in at least one etchant solution at an etching temperature less than 100.degree. C. The optical element further comprises a barrier layer intermediate the substrate and the multilayer coating. The barrier layer is relatively insoluble in the etchant solution at the etching temperature. In a second aspect of the invention, the optical element comprises a substrate and a multilayer coating as described above, and further comprises a release layer that underlies the multilayer coating. The release layer comprises a material that is relatively soluble in at least one etchant solution at an etching temperature less than 100.degree. C. In contrast to release layers of the prior art, the inventive release layer comprises germanium.