Fused Silica – SiO2

lenses, windows, mirrors, filters and prisms

Fused silica is produced by fusing high-purity silica sand, which consists of quartz crystals, at temperatures of around 1650 °C (3000 °F). This process produces a transparent glass with ultra-high purity and improved optical transmission in the deep ultraviolet. Fused silica has high working temperatures. It is used widely in the optics industry to for manufacturing precision optic components. It is used in semiconductor fabrication and laboratory equipment. Because of  its superior ultraviolet transmission it is used to make lenses and optics for the ultraviolet spectrum.

Global Optics manufacture fused silica windows, lenses, prisms and beamsplitters


Transmission Range 0.2 – 4.5 µ
Crystal Structure
Cleavage Plane None
Colour Colourless
Density 32.202
Melting Point (°) 1710 (Softening Point)
Reflection Loss 6.3% (2µ) for 2 surfaces
Solubility index Insoluble
Hardness (Knoop) 461.0
Thermal Conductivity (cal/cm sec°C) 2.82×10-3 (41°C)
Thermal Expansion coefficient (/°C) 0.5×10-6 (20-900°C)
Fused Silica (SiO2) windows and Fused Silica (SiO2) lenses

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