Abstract: The invention is directed to an arrangement for the suppression of unwanted spectral components (‘out-of-band’ radiation, as it is called) in a plasma-based radiation source. The object of the invention is to find a novel possibility for the suppression of unwanted spectral components in radiation exiting from a plasma-based EUV radiation source which permits a simple suppression of out-of-band radiation outside the desired EUV range without requiring costly manufacturing and adjustment of diffraction gratings. This object is met according to the invention in that a filter unit is provided between the plasma and an application location of the EUV radiation, which filter unit has at least one gas curtain comprising at least one rapidly flowing gas whose molecules have no absorption maxima for the desired EUV radiation and intensive absorption maxima for other, unwanted wavelengths that are emitted, at least in the IR region.