Low expansion

Low expansion materials overview

From Fused Silica to Zerodur, low expansion optical materials, as their name implies, are known for an impressively low coefficient of thermal expansion and are very resistant to high-temperature thermal shock. Typically, low expansion materials have a near zero coefficient of thermal expansion.

The material has very high mechanical strength, high chemical durability/resistance, and superior machinability characteristics. Characteristics of low expansion materials include:

  • Low coefficient of thermal expansion (CTE)
  • Large operating temperature range and shock resistivity
  • High hardness, fracture toughness
  • Permeability
  • Excellent chemical stability
  • Non-porous material
  • High affinity for coatings
  • Few inclusions and bubbles
  • Large size capabilities

Thanks to the fact that low expansion materials are chemically stable, mechanically strong and easy to polish, they are suited for applications in which temperature stability, thermal shock, or resistance to chemical attack are primary considerations.For instance, astronomical telescope mirror substrates, lightweight mirrors & mounts, laser cavities, and precision metrology fixtures. In fact, these materials are the material of choice for all of the world´s segmented telescopes currently in operation.




Photonchina offers the following low expansion materials.




Corning 7980


If you don’t see a material that you need or have any questions, please contact our sales engineer at sales@photonchinaa.com, who will response your inquiry in time.