Soft X-ray Microscope with Free-standing Zone Plates

Abstract

High resolution soft x-ray microscopes have been demonstrated by using zone plate optics (Schmahl, 1983; Kirz and Rarback, 1985). Zone plates can be fabricated by the laser holographic lithography or the electron beam lithography. The latter method is generally used because a wide variety of zone plate specifications can be achieved. The collection efficiency of the zone plate depends on its structure. It is usual that the zone plate is supported by a thin substrate. The absorptivity of the substrate material cannot be negligible in the ultra soft x-ray region.