High-power, monochromatized UV source for the study of nanostructures. It use Bragg diffraction to separate narrow band of light wavelengths. During crystal rotation user can find 4 different wavelengths of beam transferred to sample. It happens because each wavelength is reflected by crystal at different angle (Bragg reflection). So called ZERO ORDER beam – creates when monochromator crystal works similar as normal mirror – it reflects multiple wavelengths and gives highest intensitivity of transferred beam. That mode can be used when user does not need monochromated beam, but high intensitivity of UV radiation.