MULTIPLE-BEAM INTERFERENCE REFRACTOMETER AND COMPARATOR.

A multiple-beam interference refractometer nd comparator is described. This is based on the production of concentric sharp fringes of superposition due to multiple-beam interference inside a double-layer interferometer made from different media. The interferometer is compact, simple in arrangement, and easy to adjust. The center of the fringes serves as a fiducial point and a compensation method is applicable. The interferometer is applicable to the measurement of dispersion, refraction, and length with higher sensitivity than with a two-beam interference refractometer or comparator. 19 refs.