Abstract: A method for manufacturing a glass is provided, comprising converting a porous body to a multi-component glass, wherein a porous body containing at least one metal component in the form of a metal salt is immersed in a solution containing at least one compound selected from the group consisting of an acid, an ammonium salt and an alkylammonium salt to precipitate the metal salt as microcrystals in the pore. Also, a method for manufacturing a glass for use as a gradient index optical element is provided, comprising converting a porous body to a multi-component glass, wherein a porous body containing at least one metal component in the form of a metal salt is immersed in a solution containing a salt of a metal component different from the above-mentioned at least one component and at least one compound selected from the group consisting of an acid and a salt to provide the metal components with concentration distributions.

Abstract: A method of manufacturing distributed index optical elements is disclosed. The method comprises a step of preparing silica sol including at least one of metal dopants, a step of dipping, after subjecting the silica sol to a gelling treatment, the silica gel in an elute into which a part of metal constituents other than silicon including in the gel is selectively eluted, and a step of drying and sintering the silica gel.

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.

Abstract: A method of manufacturing gradient index optical element comprises preparing a sol using silicon alkoxide and a metal alkoxide as a dopant source of index-modifying cations. The sol is treated to obtain a wet gel. Metal alkoxide from the wet gel is eluted by immersing the wet gel in a solvent to produce a concentration gradiation of the metal alkoxide in the wet gel, and the wet gel is then washed. The steps of eluting and washing 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.