UV Grade Fused Silica is synthetic amorphous silicon dioxide of extremely high purity providing maximum transmission from 195 to 2100 nm. This non-crystalline, colorless silica glass combines a very low thermal expansion coefficient with good optical qualities, and excellent transmittance in the ultraviolet region. Transmission and homogeneity exceed those of crystalline quartz without the problems of orientation and temperature instability inherent in the crystalline form. It will not fluoresce under UV light and is resistant to radiation. For high-energy applications, the extreme purity of fused silica eliminates microscopic defect sites that could lead to laser damage.

Five anti-reflection coatings are available on both sides of the window, covering the spectrum range from 245 nm to 1550 nm.

Compared with other optical glasses like N-BK7, UV Fused Silica has very low autofluoresence and scattering.