A spectrometer (100) for analyzing the spectrum of an upstream light beam (1) includes an entrance slit (101) and angular dispersing elements (130). The angular dispersing elements include at least one polarization-dependent diffraction grating that is suitable for, at the plurality of wavelengths (1, 2, 3), diffracting a corrected light beam (20) into diffracted light beams (31, 32, 33) in a given particular diffraction order of the polarization-dependent diffraction grating, which is either the +1 diffraction order or the −1 diffraction order, when the corrected light beam has a preset corrected polarization state that is circular; and the spectrometer includes elements for modifying polarization (1100) placed between the entrance slit and the angular dispersion elements, which are suitable for modifying the polarization state of the upstream light beam in order to generate the corrected light beam with a preset corrected polarization state.