A spectrometer has a first and second light sources (12, 14) which generate light radiation (24) in a first and second wavelength ranges, and a mirror unit (16) for deflecting the light radiation (24, 26) into a measurement path (18), arranged so that the radiation of both wavelength ranges (24, 26) runs through on the same optical path. A detector (20) detects radiation (24, 26) running through the measurement path (18) and an evaluation unit (22) evaluates the radiation (24, 26) incident at the detector (20) and for determining a concentration of a measurement gas component present in the measurement path (18). The mirror unit (16) is configured as a micromirror array (32) and that a single micromirror (34) only deflects a portion of the radiation (24, 26).