High accuracy reflectometry technique and statistical measurements treatment method for refraction index determination

摘要

Refraction index evaluation by means of a quasi-normal incidence technique is presented. The theoretical procedure involves Fresnel equations as well as a complete statistical algorithm developed for experimental values treatment. The characteristics of the experimental technique are analyzed in depth and rules for high precision measurements are given. Refraction indices of soda lime and BK7 substrates were evaluated as function of wavelength. Accuracies of the order of 10~(-3) in refraction indices determination were obtained. Finally, and making use of high precision polishing techniques, the authors are adapting this method for the reproduction of step and graded index profile functions and diffusion depths of integrated optical waveguides.