Agency of Industrial Science and Technology

Hiroshi Yamanaka

Junji Nishii

Hajimu Wakabayashi

Ryohei Terai

Shigeo Hara

An optical micro-machining method of glass characterized in that after light is applied to glass including SiO.sub.2 and 30-70 mol % GeO.sub.2, the irradiated area is removed by etching.

Optical micro-machining method of glass

A glass material variable in volume by irradiation with ultraviolet light has a GeO.sub.2 --SiO.sub.2 glass composition having a GeO.sub.2 content of 0.5 to 90 mol %, and is in the form of a thin film formed in an argon atmosphere or in an argon-oxygen mixed gas atmosphere by the high-frequency sputtering method.

Glass material variable in volume by irradiation with ultraviolet light

This invention provides a method of producing a diffraction grating of a spectroscope by applying light to a thin film of glass having characteristics such that a density change occurs with the change of a glass structure upon irradiation of light and volume expansion occurs irreversibly. The method comprises applying light to a diffraction grating formation of a surface of the thin film by applying light through a phase mask or applying interference light, and causing the light irradiation portion of glass to expand and to thereby form the diffraction grating. Light to be applied is generally laser beams of ultraviolet rays, such as an excimer laser, a Nd-YAG laser or UV higher harmonics of a dye laser. A laser beam of a visible light region can be used, too. Preferably, a silica single crystal plate is used for the substrate of the thin film, and sputter vacuum deposition is used for forming the thin film. The glass composition whose volume expands upon irradiation of light is GeO.sub.2 --SiO.sub.2 type glass having a GeO.sub.2 content of 20 to 95 mol %, but this composition is not particularly limitative, and any glass compositions can be used so long as they have a high volume expansion coefficient.

Production method of diffraction grating

A process for vitrifying liquid radioactive waste is provided. In this process, a solution of a water-soluble vitrifying-facilitating inorganic compound in liquid radioactive waste is mixed with a solution obtained by hydrolyzing an alkyl silicate and then the solution mixture is left to gel. Thereafter, the resulting gel is irradiated with microwave to calcine the gel, and the calcined gel is further heated to melt and then cooled to obtain a vitrified product.

Growing community of inventors

Ikeda, Japan

Hiroshi Yamanaka