| 摘要 |
PROBLEM TO BE SOLVED: To obtain an absolute value of an unknown phase difference, by measuring concurrently a sample of unknown phase difference and a reference wavelength plate having a known phase difference. SOLUTION: This instrument 20 for measuring a double refraction phase difference of a material comprises a laser beam, a slit optical lens, a polarizer, the first 1/4 wavelength plates, known reference double refraction plates, the second 1/4 wavelength plates, analyzers, and photodetectors, and the measuring sample is arranged between the first 1/4 wavelength plate and the known reference double refraction plate. A light intensity distribution of only the unknown phase difference, and a light intensity distribution of the unknown phase difference + the reference double refraction plate known phase difference are measured concurrently by the photodetector 11, and the absolute value of the unknown phase difference of the sample is found thereby to measure a double refraction phase difference. Three half-mirrors 13a, 13b, 13c are arranged therein on an optical path axis in a rear side of the measuring sample to branch an optical path into three optical paths, the three known reference double refraction plates are arranged on the three optical paths to be directed toward three directions of 0°, 90°and 45°, transmission laser beams transmitted through the three optical paths are detected by the three photodetectors 11, the unknown phase differences are superposed respectively to determine a principal axial direction univalently. COPYRIGHT: (C)2007,JPO&INPIT
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