GRIN elements in the interference method of glass index measurement

A new interference method for measurement of the refractive index of glass has been developed. The method is based on the Mach-Zehnder interferometry and GRIN elements are used for a scale of refractive index. Cone, pyramid or wedge elements are privileged in this method. Both the object under study and GRIN elements are placed in an oil immersion container, then oil is heated until the specimen becomes invisible. For such a situation the interference fringes produced by the GRIN standard are analyzed. The accuracy of refractive index measurements is equal to +/- 0.00001.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.