Preliminary Survey of Material Pairs for XUV Multilayer Mirrors for Wavelengths Below 130 Å

Abstract

Remarkable progress, within limited wavelength ranges, has been made in the field of normal incidence XUV mirrors. High performance Mo/Si multilayer mirrors exist for wavelengths between 125 and ~250 Å, and reflectivities greater than 60% have been achieved around 130-140 Å.1-4 Good results were also obtained with C and B4C-based multilayer mirrors at wavelengths just above the C and the B K-absorption edges at 44 Å and 67 Å, respectively.5-7 However, there are wavelength regions such as the water window or just below the Si L-edge, where none of the well-established material pairs can achieve reflectivities adequate for many applications. The search for new material pairs to bridge these wavelength gaps has motivated the work that is briefly discussed here.