| 摘要 |
The present invention causes measurement light emitted from an object to be measured to enter a fixed mirror unit and a movable mirror unit and forms interference light of measurement light reflected by the fixed mirror unit and measurement light reflected by the movable mirror unit. At this time, a change of the intensity of the interference light of measurement light is obtained by moving the movable mirror unit, and an interferogram of measurement light is acquired based on the change. At the same time, reference light of a narrow wavelength band included in a wavelength band of the measurement light is caused to enter the fixed mirror unit and the movable mirror unit, and interference light of the reference light reflected by the fixed mirror unit and the reference light reflected by the movable mirror unit is formed. At this time, the movable mirror unit is moved to correct the interferogram of measurement light based on an amplitude of the change of the interference light of the reference light and based on a phase difference between measurement light, which is at the same wavelength as the reference light in the measurement light, and the reference light, and a spectrum of the measurement light is acquired based on the corrected interferogram. |
