A method of determining the refractive index of glasses in wide mid-infrared

We propose a method of merging the minimum deviation and the interferometric method to determine the refractive index dispersions of glasses in a wide range of the mid-infrared region with high accuracy. By the proposed method, the refractive index dispersions of telluride glasses, included in chalcogenide glasses, are successfully determined in the wavelength range from 3 to around 20 mu m. The accuracy of the refractive index by the proposed method is no more than 1 x 10(-3).