The Precise Control of Refractive Index Distribution Shape SiO₂-TiO₂-BaO-K₂O System Radial Grin Lens by Improving the Flow of Immersing Solution through the Sol-Gel Method

Abstract

It is necessary to apply r-GRIN lens for high-performance optical system that the control of more highly precise distribution shape is expected. So we prepared the sol and gel, which had high concentration barium using planetary mixer, and examined to control the refractive index distribution of the r-GRIN lens. And we improved a flow of the gel immersing solutions smoothly, and examined the gel immersing conditions. We were able to find out suitable condition, in which 95% gels were without cracking and without cloud of immersing solution. We succeed to prepare the low distributed dispersion r-GRIN lens whose diameter was 4mm , Δn was 0.07 and projection resolution was 125 line / mm. The difference in the refractive index distribution between the r-GRIN lens and ideal parabolic distribution was 0.5λin range of ø2.6 mm.