OPTICAL CHARACTERISTICS MEASURING APPARATUS, AND OPTICAL CHARACTERISTICS MEASURING METHOD
Linearly-polarized light reaching a sample (S) via a polarizer is provided with retardation by the sample (S), and then reaches a movable mirror portion (131) and a fixed mirror portion (132) of a phase shifter (13) via a first polarizing plate (9) and a second polarizing plate (11). Measurement light reflected by these mirror portions is passed through an analyzer (15) and an imaging lens (17) by which an interference image is formed on a light-reception surface of a detector (19). At this time, by moving the movable mirror portion (131), an optical path length difference between a light flux reflected by the movable mirror portion (131) and a light flux reflected by the fixed mirror portion (132) can be continuously varied. As a result, the imaging intensity of the interference image detected by the detector (19) is continuously varied, and a composed waveform similar to an interferogram can be acquired. Subjecting the composed waveform to Fourier transform yields amplitude on a wavelength basis and a birefringent phase difference on a wavelength basis.