Abstract

Recently there have been many experimental and theoretical studies of diffraction gratings coated with short-period multilayers to enhance their reflectivity in the extreme ultraviolet and x-ray regions. Much of this work has been focussed on lamellar gratings, but there is also considerable interest in multilayer coated blazed gratings. Until now, these blazed gratings have been made by traditional ruling. In an interferometrically controlled ruling engine this leads to very accurate groove placement, but the quality of the groove surfaces may be poor because the grooves are burnished into a soft material such as gold. This leads to low multilayer reflectivity because the substrate roughness (in this case the groove surface) is an important factor in determining its performance. In addition the gratings can be used only in low orders, since operation in higher orders requires excellent groove profile.

© 1994 Optical Society of America