| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a precise measuring method of the group refractive index of an optical material, capable of easily and accurately measuring the group refractive index, without requiring the thickness data of a sample to be measured and capable of simplifying and miniaturizing a measuring instrument, and a precise measuring instrument therefor. <P>SOLUTION: The incident light from a low-coherence light source is separated into a first optical path 5 and a second optical path 6 by a beam splitter 2, and the reflected light from the first mirror 11 of the first optical path 5 and the reflected light from the second mirror 9 of the second optical path 6 are guided to a retroreflector 3 from the beam splitter 2; while the optical axes of both reflected lights are made to coincide with each other. The reflected light from the retroreflector 3 is separated into a third optical path 8 and a fourth optical path 7 by the beam splitter 2, and the optical axis of the reflected light from the third mirror 10 of the third optical path 8 is allowed to coincide with that of the reflected light from the second mirror 9 of the fourth optical path 7 to detect the reflected light from the beam splitter 2 by a photodetector 4. An interferometer, constituted so that the same functions as those of an interferometer consisting of the series connection of two interferometers are performed by one interferometer, is used. The sample 13 to be measured is arranged to the first optical path 5 and compensation plates 14 and 15 comprising the same material as that of the sample 13 to be measured are arranged to the second and fourth optical paths 6 and 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
