Fused silica, UV fused silica, low OH fused silica

Fused silica, composed of high-purity silicon dioxide (SiO2), is an advanced optical material created through a process that involves melting silica sand at extremely high temperatures. This molten material is then rapidly cooled to form an amorphous glass, resulting in outstanding optical transparency across a wide wavelength spectrum, ranging from ultraviolet (UV) to near-infrared (NIR), typically spanning 185nm to 2.5μm.

The thermal properties of fused silica are exceptional. With a low coefficient of thermal expansion, remarkable thermal stability, and strong resistance to thermal shock, it is well-suited for environments subject to extreme temperature fluctuations. These characteristics are invaluable in high-performance optical systems, particularly in laser applications, where maintaining consistent optical performance under varying temperatures is crucial.

Mechanically, fused silica is known for its high hardness, low thermal expansion, and excellent resistance to scratching and abrasion. These attributes contribute to its reliability and durability, even in the most demanding optical environments. Its applications are diverse and include the production of optical components such as lenses, windows, prisms, and mirrors, which are vital in fields like laser technology, spectroscopy, microscopy, and semiconductor manufacturing. For instance, in laser systems, fused silica optics enable efficient operation by transmitting laser light with minimal absorption and scattering, ensuring precise beam control. In spectroscopy, its high optical clarity and low fluorescence facilitate accurate measurement and analysis of light spectra.

Low OH fused silica is a specialized variant designed to have minimal hydroxyl group (-OH) impurities. Hydroxyl impurities are common in silica-based materials and can impair optical performance, particularly in the infrared range. The production of low OH fused silica involves a meticulous process to ensure the purity of raw materials and to minimize hydroxyl introduction during manufacturing. This results in enhanced optical transmission, especially in the near-infrared (NIR) and mid-infrared (MIR) ranges, making it ideal for precision optical applications.

In conclusion, fused silica stands out as a versatile and indispensable material in advanced optical systems and devices. Its exceptional optical transparency, thermal stability, mechanical durability, and adaptability across industries make it a cornerstone of cutting-edge technologies.

Optical Grade Fused Silica/Quartz Properties

Optical grade fused silica and UV fused silica , also known as quartz glass, exhibits outstanding properties that make it essential for high-precision applications. Its transmission range spans from 180nm to 2000nm for synthetic variants, and 275nm to 2000nm for natural fused silica, ensuring excellent optical clarity across ultraviolet (UV), visible, and near-infrared (NIR) wavelengths. The refractive index is precisely measured at 1.458 (n D) at 589nm, optimizing its suitability for optical components.

Chemically, fused silica boasts an impressive silicon dioxide (SiO2) content of 99.995%, with total metallic impurities typically below 10ppm, contributing to its remarkable purity. The material has a density of 2.20g/cm³ and a hardness of 580 KHN, ensuring robust resistance to physical wear and abrasion. Additionally, it features a tensile strength of 4.8×10⁷ Pa and a compressive strength of 1.1×10⁹ Pa, making it mechanically durable for demanding environments.

Fused silica’s thermal properties are equally exceptional. It has a low coefficient of thermal expansion, measured at 5.5×10⁻⁷ cm/cm°C (from 20°C to 320°C), ensuring stability in applications requiring minimal dimensional changes under varying temperatures. Its thermal conductivity stands at 1.4 W/m°C, coupled with a specific heat of 670 J/kg°C, enabling efficient heat dissipation. The softening and annealing points are 1700°C and 1215°C respectively, making it highly resistant to thermal deformation.

From an electrical perspective, fused silica possesses outstanding characteristics for precision applications. It has an electrical resistance of 7×10⁷ ohm.cm at 350°C and a dielectric constant of 3.74 (at 10GHz). Furthermore, it exhibits a dielectric strength of 3.7×10⁷ V/m and an exceptionally low dielectric loss factor of 0.0002 (10GHz).

The refractive indices for various wavelengths are carefully calibrated: ng = 1.46679, nf = 1.46324, ne = 1.46021, nd = 1.45857, and nc = 1.45646. These precise values highlight the material’s reliability for high-performance optical systems.

Fused silica/quartz properties vary based on the grade and manufacturing process. Its ability to maintain consistency in optical, thermal, and mechanical performance makes it indispensable in industries such as laser technology, spectroscopy, semiconductor manufacturing, and advanced optics.