INTERFEROMETER AND SPECTROMETER INCLUDING SAME

摘要

An optical path of measurement light emitted from a measurement light source is overlaid by a beam combiner on an optical path of reference light emitted from a reference light source. The measurement light emitted from the measurement light source includes light in the sensitivity wavelength range (S1) of a measurement light detector and light in the sensitivity wavelength range (S2) of a reference light detector. An interferometer includes a wavelength separation filter that cuts light in at least a part of the sensitivity wavelength range (S2) of the reference light detector, of light included in the wavelength range of the measurement light.

主权项

1. An interferometer comprising:
a measurement light source that emits measurement light; a measurement light detector that detects the measurement light; a reference light source that emits, as reference light, laser light whose wavelength is shorter than a sensitivity wavelength range of the measurement light detector; a reference light detector that detects the reference light; a beam combiner that overlays an optical path of the measurement light and an optical path of the reference light; a first beam splitter that separates, into two light beams, each of the measurement light and the reference light entering through the beam combiner; a first reflective member that is arranged on an optical path of one of the two light beams separated by the first beam splitter and that reflects and makes each of the measurement light and the reference light enter the first beam splitter again; a second reflective member that is arranged on an optical path of the other of the two light beams separated by the first beam splitter and that reflects and makes each of the measurement light and the reference light enter the first beam splitter again; and a second beam splitter that separates, into two light beams, light which is subjected to interference in the first beam splitter and emitted by the first beam splitter, and that guides the light beams to the measurement light detector and the reference light detector, respectively, wherein, based on a result of detection by the reference light detector when the first reflective member and the second reflective member are relatively moved, the interferometer measures the measurement light while detecting an optical path difference of the two light beams separated by the first beam splitter, the measurement light emitted from the measurement light source includes light in a sensitivity wavelength range of the measurement light detector and light in a sensitivity wavelength range of the reference light detector and the interferometer further includes a wavelength separation filter that cuts light in at least a part of the sensitivity wavelength range of the reference light detector, of light included in a wavelength range of the measurement light.