PHOTOREFRACTIVE GLASS AND OPTICAL ELEMENTS MADE THEREFROM

摘要

The present invention provides an alkali alumino-silicate Na-F-containing glass material and a method of making the alkali alumino-silicate Na-F-containing glass material, with the glass material capable of being made photosensitive and thus formed into optical elements at wavelengths ranging between about 240 to 350 nm, and more particularly at the standard 248nm wavelength of excimer lasers. Also disclosed is optical element wherein a refractive index pattern formed in the alumino-silicate Na-F containing glass material, the refractive index pattern including regions of high refractive index and regions of low refractive index, the difference between the refractive indices of the high refractive index regions and the low refractive index regions being at least 4x10<-5> at a wavelength of 633 nm.