Measurement of the chromatic variation of index of refraction gradients.

The theory of multiple-wavelength ac interferometry has been developed. A system has been constructed and used to measure simultaneously the index of refraction profile and the chromatic variation of the index of refraction gradient. Samples of gradient-index glass manufactured by Bausch & Lomb (Rochester, N.Y.), University of Rochester (Rochester, N.Y.), and Schott Optical (Mainz, West Germany) have been characterized.