Patent attributes
A silica glass containing TiO2, characterized in that the fluctuation of the refractive index (Δn) is at most 2×10−4 within an area of 30 mm×30 mm in at least one plane. A silica glass containing TiO2, characterized in that the TiO2 concentration is at least 1 mass %, and the striae pitch is at most 10 μm. An optical material for EUV lithography, characterized in that it is made of a silica glass containing TiO2, and the fluctuation of the refractive index (Δn) is at most 2×10−4 in a plane perpendicular to the incident light direction. An optical material for EUV lithography, characterized in that it is made of a silica glass containing TiO2, wherein the TiO2 concentration is at least 1 mass %, and the difference between the maximum value and the minimum value of the TiO2 concentration is at most 0.06 mass % in a plane perpendicular to the incident light direction.
