| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for easily and accurately measuring a group refractive index, which eliminates the need for thickness information of a sample to be measured. SOLUTION: An interferometer system is made up by serially connecting a first interferometer 2 of a Michelson type or the like and a second interferometer 3 of the same type, and uses low-coherence light source as its light source. Then, an optical material to be measured 13 whose group refractive index is measured, and a first compensating plate 14 made of the same material are disposed at the first interferometer 2, and a second compensating plate 15 is disposed at the second interferometer. A mirror in the interferometer system is scanned in the direction of its optical axis, while changing optical paths, and positions where low-coherence interference fringes appear, are measured two or more times, and the group refractive index is calculated based on the positions. In another method, the optical material to be measured whose group refractive index is measured, and one compensating plate made of the same material are employed in a triangular optical path interferometer. While the optical material to be measured is operated together with the compensating plate in the direction of its optical axis, the positions where the low-coherence interference fringes appear, are measured, and the group refractive index is calculated. COPYRIGHT: (C)2005,JPO&NCIPI
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