Method for producing a substrate for an optical element, and reflective optical element

Abstract

A reflective optical element (11), in particular for reflecting EUV radiation (14) includes: a substrate having an optical surface on which a reflective coating (13) is applied. The substrate has a quasi-monocrystalline volume region (8). An associated method for producing the substrate (10) for the optical element (11) includes: introducing a starting material, preferably a metal or a semimetal, into a container and melting the starting material, producing a material body having a quasi-monocrystalline volume region (8) by directionally solidifying the molten starting material proceeding from a plurality of monocrystalline seed plates arranged in the region of a base of the container, and producing the substrate by processing the material body to form an optical surface (12).

Dependencies are inferred from the claim text.