To acquire a spectroscopic device which effectively reduces incidence upon a light detection unit of stray light reflected by surfaces other than a diffraction surface, and is capable of detecting light dispersed by the diffraction surface with high accuracy.
In the spectroscopic device with a concave reflection-type diffraction element, non-diffraction surfaces being on the same side as the diffraction surface of the diffraction element and located outside the diffraction surface are glossy, among surfaces other than the diffraction surface, and the device includes a light detection unit at a position corresponding to an imaging position of first-order diffracted light diffracted by the diffraction element to receive the first-order diffracted light. The light detection unit is disposed inside optical paths of light beams reflected regularly by the non-diffraction surfaces outside the diffraction surface.
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KIMURA KAZUMI
TOCHIGI NOBUYUKI
TAKIZAWA TOKUJI
