Abstract: The invention relates to an optical device intended to treat an incident X-ray beam. The optical device comprises a monochromator and an optical element for conditioning the incident beam. The reflective surface of the optical element is able to produce a two-dimensional optical effect in order to adapt a beam in destination of the monochromator. The reflective surface of the optical element comprises a multilayer structure type surface that is reflective to X-rays. In particular, the reflective surface consists of a single surface shaped according to two curvatures corresponding to two different directions.

Abstract: This invention relates to an optical assembly (10) with a laterally graded reflective multilayer whose reflecting surface reflects incident X-rays under low incidence angles producing a two-dimensional optical effect, characterized by the fact that said reflecting surface is comprised of a single surface, said reflecting surface being conformed along two curvatures corresponding to two different directions. This invention also relates to a manufacturing method of such an optical assembly, characterized in that the method includes the coating of a substrate already having a curvature, and the curvature of this substrate along a second different direction.