Abstract

High-quality radial gradient-index glass based on the TiO₂-SiO₂ and ZrO₂-SiO₂ systems has been prepared using solgel techniques. The use of additional components such as AI₂O₃, B₂O₃, and GeO₂ helps to eliminate the problems of gel fracture, bloating, and crystallization. In all cases, the precursor gels are prepared from metal alkoxides, water, alcohol, and a small amount of acid catalyst. The refractive-index gradient is created by selectively leaching the TiO₂ or ZrO₂ component from the precursor gel by placing the gel in an aqueous acid solution. The leaching process is halted by placing the gel in methanol. The gel is then dried in an oven and then sintered into glass by heating to temperatures as high as 1500°C. Plane-faced gradient-index lenses have been made with diameters >8 mm and index changes >0.02.

© 1987 Optical Society of America