A device for testing the quality of microstructurization of a surface (2) having a known target microstructurization quality, comprising a radiation source (1) for coherent radiation, a first detector (10) and a second detector (4) and a masking system, all of which are set up and arranged with respect to one another so that radiation emitted by the radiation source (1) onto the surface (2) produces a diffraction pattern, wherein the diffraction maximum of order n of the diffraction pattern without the masking system would impinge on the first detector (10), the masking system prevents 80% of the photons that are assigned to the diffraction maximum of order n from impinging on the first detector and the diffraction maximum of order a of the diffraction pattern impinges on the second detector (4), wherein n is selected from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 and a is selected from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 and a≠n.