Fused Silica Window

Features of Fused Silica Window

Optical Properties:

Fused silica windows have maximum transmittance in the wavelength range of 185 to 2100 nanometers, with particularly excellent transmittance in the ultraviolet region, and they do not fluoresce under UV light. Compared to other optical glasses like N-BK7, fused silica has higher transmittance in the deep UV range, as well as a lower refractive index and thermal expansion coefficient.

Thermal Properties:

Fused silica windows have an extremely low thermal expansion coefficient and good thermal resistance. The thermal expansion coefficient is only 0.54×10^-6/°C from 0°C to 800°C, which means they undergo minimal volume change in high-temperature environments and have excellent thermal shock resistance. Additionally, fused silica has good erosion resistance at high temperatures; even at 2000°C, its viscosity is 100 times higher than that of ordinary glass melts.

Mechanical Properties:

Fused silica windows exhibit good chemical stability and corrosion resistance, reacting with almost no acids or bases except for concentrated phosphoric acid and hydrofluoric acid above 300°C. Their flexural strength increases with temperature; for example, the flexural strength at 1000°C is 30%-60% higher than at room temperature.

Electrical Properties:

Fused silica windows have excellent insulating properties, with a resistance of 10^15Ω at room temperature, a dielectric constant of 3.1-3.8, and a dielectric loss of 4×10^-4.

Application of Fused Silica Window

Optical Field: 

Fused silica windows are widely used in optical instruments due to their excellent optical and mechanical properties. They offer high transmittance, low stress birefringence, and good thermal resistance, making them suitable for high-stability optical systems in harsh environments. For example, fused silica windows perform exceptionally well in optical systems such as spacecraft, wind tunnel windows, and spectrophotometers.

Laser Technology: 

Fused silica windows also play a significant role in laser technology. Due to their excellent thermal resistance and low thermal expansion coefficient, fused silica windows can withstand high-power laser irradiation, making them suitable for applications in lasers, laser cutting, and laser processing.

Aerospace and Military: 

In the aerospace and military fields, fused silica windows are used in transparent components of satellites, rockets, and missiles due to their superior thermal resistance and radiation resistance. These components need to operate in extreme temperature and radiation environments, and fused silica windows can meet these requirements.

Industrial Applications: 

In the industrial sector, fused silica windows are commonly used as transparent observation windows in high-temperature furnaces, reactors, and chemical equipment. Their high-temperature and corrosion resistance make them perform excellently in these high-temperature, corrosive environments.

Research and Education: 

Fused silica windows also play an important role in research and education. Due to their high transmittance and low stress birefringence, they are used in laboratory equipment and educational instruments, providing clear and stable observation effects.