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Fused Silica in Optical Components

September 30, 2020

Optics are critical to a range of applications, from analytical devices to communications equipment, medical diagnostic equipment, aerospace instruments, and defense apparatus. They are used for diffraction, reflection, refraction, and diffusion of a variety of light wavelengths to enhance, magnify, and direct light through clear lenses and optical components.

Due to the highly precise nature of optical applications, optical components must be manufactured with a high degree of clarity and accuracy. Fused silica, also known as fused quartz, is of particular interest for optical applications. Valued for its exceptional clarity, durability, and thermal properties, it can be used in extreme environments that are inhospitable for other materials.

What Is Fused Silica?

Fused silica is a noncrystalline glass composed of silicon dioxide. It is different from other forms of glass in that it is formulated using only one ingredient: high-purity crystalline silica. The resultant glass is extremely transparent, hard, and temperature-resistant. Fused silica’s noncrystalline composition features cross-linked atoms in three dimensions, which facilitates the material’s extreme temperature resistance and exceptionally low coefficient of thermal expansion (CTE).

Why Use Fused Silica for Optical Components?

In optics, fused silica offers exceptional UV transmission, and can be manufactured to facilitate the transmission of infrared wavelengths. Coupled with low refractive index variations, it exhibits ideal optical qualities for high-precision optics applications. In addition, the physical properties of fused silica glass make it particularly useful for high-performance applications in harsh conditions. Among its most useful characteristics are:

  • Exceptional corrosion resistance
  • High chemical purity
  • Extremely low permeability
  • Extreme hardness
  • Low refractive variation

Thermal Properties

Fused silica exhibits particular thermal properties that make it ideal for use in optical parts. With a low coefficient of thermal expansion (CTE) and extremely high-temperature resistance, the accuracy of optical components made of fused silica can be relied upon even in high-temperature applications. Fused silica’s thermal conductivity is extremely low, so it acts as an excellent thermal insulator. Its extreme resistance to thermal shock allows fused silica to withstand extreme temperature fluctuations during the manufacturing process, making it easier to rapidly quench silica glass components without compromising the strength of the material.

What Optical Applications Use Fused Silica?

Fused silica’s high strength and unique thermal characteristics make it well suited to a variety of optical applications that require a high level of durability, accuracy, and resistance to broad temperature fluctuations.

Some of the most common optical applications that benefit from fused silica components include:

  • Temperature insensitive optical component supports
  • High-temperature lamp envelopes
  • Microwave and millimeter wave components
  • Lenses and mirrors in highly variable temperature regimes
  • Aeronautical radar windows

Dependable Fused Silica Components From OPCO

At OPCO Laboratory, Inc., we provide the highest quality optical components and assemblies for precision light management, from lenses and mirrors to test plates, filters, and beam splitters. All of our components are manufactured using the highest quality materials available, including germanium, low- and high-index glass, sapphire, and fused silica.

We also offer a wide range of specialized coatings, including anti-reflective, metallic, dielectric, ITO, and many others. To learn more about our quality optical components and assemblies, visit our optical products page.