Shin-Etsu’s VIOSIL(Synthetic Quartz Glass Substrate) features high purity and high transmissivity over a wide range of wavelengths from infrared to ultraviolet. It also has high stabiity against a variety of solvents and under high temperatures, and furthermore, non self fluorescence and low dielectric loss at GHz frequencies. Thanks to these excellent characteristics, Shin-Etsu’s VIOSIL is applied to extensive fields.