Optimum preparation conditions for SiO2-TiO2-BaO-K2O system radial GRIN lens by quality engineering and expansion of its Δn

Abstract

There is growing interest in applying an r-GRIN lens to small and simple optical systems, so that the refractive index difference, Δn, of the r-GRIN lens is ≧ 0.04. In this study, a sol was prepared, which had high concentration of barium, using a planetary mixer in order to expand the Δn of the r-GRIN glass. Sol preparation and wet gel treatment conditions were examined using Quality Engineering, which is one of the available statistical analysis methods. According to this method, the optimum conditions could be located. r-GRIN glasses with low distributed dispersion, Δn of 0.035, and a resolution of 100 lines per 1 mm could be prepared. Furthermore, we succeeded in expanding the Δn value up to nearly 0.05 by increasing the volume of the concentration distribution solvent.