The invention is directed to a highly sensitive spectrum analysis unit with a diffraction grating, wherein a parallel light bundle having a wavelength range impinges on a diffraction grating which splits the different wavelengths into spectra by diffraction in first directions, and wavelength partial ranges of the spectrally split light bundle can be focused on a detector row by means of camera optics, and evaluation electronics are connected to the detector row and acquire the generated spectrum as information and display it. The invention is characterized in that the light bundle passes a first optical element, and then wavelength partial ranges of a spectrally split light bundle impinge on respective partial regions of a diffraction grating, the diffraction grating having the same grating constant across all partial regions and a changing profile shape, the profile shapes generating different blaze wavelengths that lie in the respective wavelength partial ranges.