Patent ID: 9638577
Date: 2017-05-02
CPC Classifications: G01J

Claim:
1. A spectrometer comprising: spectral dispersion means of an initial light beam; and a photodetector, to measure light intensity of an incident light beam; wherein the spectrometer does not form a closed cavity, and the spectral dispersion means comprises at least three reflective diffraction gratings parallel to consecutive sides of a convex polygon, arranged such that: a portion of the initial light beam is diffracted once by each of the diffraction gratings in turn and is diffracted at least a second time by at least one of the diffraction gratings, this portion of the initial light beam forming the incident light beam on the photodetector; and the optical path followed by the portion of light beam connects directly, without intermediate reflection on an interposed mirror, a first diffraction grating to a second diffraction grating, the second diffraction grating to a third diffraction grating, and the third diffraction grating to the first diffraction grating.