Abstract: Disclosed is a spectroscopy device, including an analysis zone for receiving a sample; at least one light-emitting diode arranged to emit a light beam towards the analysis zone, having a luminous intensity spectral profile in a working wavelength interval; unit for varying with time the luminous intensity spectral profile emitted by the diode in the working wavelength interval of the diode; a detector, arranged to receive, during a variation with time of the luminous intensity spectral profile emitted by the diode, the light beam emitted by the diode and having crossed the analysis zone, and supplying a detection signal of the light beam emitted by the diode and received by the detector, in the form of a signal which depends on at least one characteristic representative of the luminous intensity spectral profile of the light-emitting diode. Application to derivative spectroscopy.

Abstract: An emission device (1) for emitting a light beam of controlled spectrum, includes: at least two separate light sources (Si to N) each emitting a light beam of wavelength ?1 or ?2, and spectral multiplexing elements (25). The spectral multiplexing elements (25) include an optical assembly (25) formed from at least one lens (25) and/or an optical prism. The optical assembly (25) has chromatic dispersion properties and moves the light beams spatially closer together. Moreover, each light beam having at least wavelength ?1 or ?2 propagates in free space from the corresponding light source (Si to N) to the optical assembly (25). Therefore the emission device (1) is particularly robust. It can have small dimensions and be produced at low cost.