The invention refers to a method for analyzing a defect of an optical element for the extreme ultra-violet wavelength range comprising at least one substrate and at least one multi-layer structure, the method comprising the steps: (a) determining first data by exposing the defect to ultra-violet radiation, (b) determining second data by scanning the defect with a scanning probe microscope, (c) determining third data by scanning the defect with a scanning particle microscope, and (d) com-bining the first, the second and the third data.