Temperature-robust calibration path optical design

A spectrometer device for obtaining spectroscopic information on at least one object, wherein the spectrometer device comprises

• at least one detector for detecting detection light from the object;
• at least one optical filter configured for transferring incident light within at least one selected wavelength range onto the detector, wherein a transmission profile of the optical filter is dependent on an angle-of-incidence;
• at least one light source configured for emitting illumination light in at least one optical spectral range;
• at least one sample interface configured for allowing the illumination light to illuminate the object and configured for allowing light from the object to propagate via the optical filter to the detector;
• at least one first optical path, wherein the first optical path is configured for allowing the illumination light to propagate via the optical filter to the detector by passing the sample interface at least once, wherein the optical filter has a first transmission profile T1,NBP for the first optical path;
• and
• at least one internal calibration target and at least one second optical path, wherein the second optical path is configured for allowing the illumination light to propagate via the optical filter to the detector by interacting with the internal calibration target at least once, wherein the optical filter has a second transmission profile T2,NBP for the second optical path;
• wherein the transmission profiles of the optical filter of the first and the second optical paths are proportional to each other with T1,NBP(λ)=d·T2,NBP(λ) with d being independent of one or more of temperature, wavelength, or angle-of-incidence, wherein the optical filter, the light source, the sample interface and the internal calibration target are arranged such that the transmission profiles of the first optical path and the second optical path are identical.