Spectrometer for analysing the spectrum of a light beam

摘要

A spectrometer (100) for analyzing the spectrum of an upstream light beam (1), includes an entrance slit (101) and collimating elements (110) suitable for generating, from the upstream light beam, a collimated light beam (10), characterized in that it also includes: a polarization-dependent diffraction grating (120) suitable for diffracting, at each wavelength (11, 12) of the spectrum of the upstream light beam, the collimated light beam into a first diffracted light beam (11, 12) and a second diffracted light beam (21, 22); optical recombining elements (130) including a planar optical reflecting surface (130) perpendicular to the grating and suitable for deviating at least the second diffracted light beam; and focussing elements (140) suitable for focussing, at each wavelength, the first diffracted light beam and the second diffracted light beam onto one and the same focussing area (141).

主权项

1. A spectrometer for analyzing the spectrum of an upstream light beam, the spectrometer comprising:
an entrance slit that lets said upstream light beam therethrough; a collimation system configured to generate, from said upstream light beam, a collimated light beam; an angular dispersion device configured to intercept said collimated light beam and to angularly disperse said collimated light beam according to a plurality of wavelengths, said angular dispersion device comprising at least one polarization-separation diffraction grating that has a normal N to the grating, said polarization-separation diffraction grating being configured to diffract said collimated light beam into:
at least one first diffracted light beam according to a first diffraction order that is either the diffraction order +1, or the diffraction order −1 of said polarization-separation diffraction grating, said first diffracted light beam being angularly diffracted according to said plurality of wavelengths and having a first polarization state that is circular, anda second diffracted light beam according to a second diffraction order that is either the diffraction order +1, or the diffraction order −1 of said polarization-separation diffraction grating, said second diffraction order being different from said first diffraction order, said second diffracted light beam being angularly diffracted according to said plurality of wavelengths and having a second polarization state that is circular and orthogonal to said first polarization state; an optical recombination system disposed at least on an optical path of said second diffracted light beam, downstream of said polarization-separation diffraction grating, said optical recombination system comprising at least one planar optical-reflection surface parallel to said normal N to the grating that is configured to deviate at least said second diffracted light beam; and a focusing system configured to focus, for each wavelength of said plurality of wavelength, said first diffracted light beam and said second diffracted light beam to a same focusing surface.