Method of manufacturing gradient index optical elements

Abstract

A method of manufacturing a gradient index optical element comprises preparing a sol using silicon alkoxide and an aqueous metal salt solution as a source of index-modifying cations. The sol is treated to obtain a wet gel. Metal salt from the wet gel is eluted by immersing the wet gel in a solvent to produce a concentration gradiation of the metal salt in the wet gel. The metal salt is fixed in the wet gel by immersing the wet gel in a solvent. The steps of eluting and fixing are repeated so that a gradient index optical element is produced having a large difference in refractive index between the outer periphery portion and the center of the gel.