Abstract: An optical element (14), in particular for EUV lithography, includes a substrate (15), a reflective coating (16) arranged on the substrate (15), and an electrically conductive coating (19) extending between the substrate and the reflective coating, and having at least one first layer (22a) under tensile stress and at least one second layer (22b) under compressive stress. The electrically conductive coating has at least one section (20) that extends on the substrate laterally beyond the reflective coating. Also disclosed is an optical assembly, in particular an EUV lithography system, provided with at least one optical element of this type.

Abstract: A reflective optical element (50) having a substrate (52) and a multilayer system (51) that has a plurality of partial stacks (53), each with a first layer (54) of a first material and a second layer (55) of a second material. The first material and the second material differ from one another in refractive index at an operating wavelength of the optical element. Each of the partial stacks has a thickness (Di) and a layer thickness ratio (?i), wherein the layer thickness ratio is the quotient of the thickness of the respective first layer and the partial stack thickness (Di). In a first section of the multilayer system, for at least one of the two variables of partial stack thickness (Di) and layer thickness ratio (?i), the mean square deviation from the respective mean values therefor is at least 10% less than in a second section of the multilayer system.