OPTICAL MEMBER COMPRISING SILICA GLASS CONTAINING TiO2

摘要

The present invention relates to an optical member including a TiO 2 -containing silica glass having: a TiO 2 concentration of from 3 to 10% by mass; a Ti 3+ concentration of 100 wt ppm or less; a thermal expansion coefficient at from 0 to 100°C, CTE 0-100 , of 0±150 ppb/°C; and an internal transmittance in the wavelength range of 400 to 700 nm per a thickness of 1 mm, T 400-700 , of 80% or more, in which the optical member has a ratio of variation of Ti 3+ concentration to an average value of the Ti 3+ concentration, ”Ti 3+ /Ti 3+ , on an optical use surface, is 0.2 or less.