A diaphragm device with which individual wavelengths or ranges of wavelengths in the path of a beam of spectrally dispersed light can be suppressed. Such a diaphragm device comprises at least one array of diaphragms, wherein the individual diaphragms of the array are arranged in a definite relation to each other and may be coupled in the path of the beam and each diaphragm of the array in the coupled state is arranged in a given relation to an individual wavelength or a range of wavelengths.