Approach opposing laying out the slant face

摘要

PROBLEM TO BE SOLVED: To perform high-accuracy refractive index measurement which is also usable for a refractive-index standard measuring device by enhancing the accuracy of interference measurement.;SOLUTION: A prism pair is formed by arranging a slant surface 11 of a prism 1 to be measured and a slant surface 21 of a compensating prism 2 so as to face them closely, and this pair is arranged in an interferometer such as a Mach-zehnder interferometer, and the amount of movement of the prism to be measured is measured with a laser length measuring device 10. The prism to be measured is moved in parallel in its surface facing the compensating prism, an optical path length in the prism to be measured in the interferometer is changed, and the refractive index of the prism is found from the relation between that change in optical wavelength in the prism to be measured, and the amount of movement of the prism to be measured with the laser length measuring device. The object to be measured can be a prism, a wedge, or even a container in the shape of either of them filled with a liquid. Moreover various two-beam interferometers can be used, and incidence to the prism can also be performed in various ways.;COPYRIGHT: (C)2009,JPO&INPIT