UV Fused Silica (UVFS) is a high-purity amorphous silica glass with exceptional transmission from the deep UV through the near infrared. Its low coefficient of thermal expansion and high laser damage threshold make it the material of choice for high-power laser and UV applications.
High-power laser systems
UV lithography and inspection
Spectroscopy and analytical instruments
High-precision reference optics
Semiconductor manufacturing equipment
| Property | Value |
|---|---|
| Coefficient of Thermal Expansion (CTE) | 0.55 × 10⁻⁶ /K |
| Thermal Conductivity | 1.38 W/m·K |
| dn/dT (Thermo-optic Coefficient) | 12.8 × 10⁻⁶ /K at 633 nm |
| Maximum Operating Temperature | ~1000°C (strain point 1070°C) |
UV fused silica has the lowest thermal expansion among common optical materials, making it ideal for precision optics in varying thermal environments.
Standard coating types available for this material. Custom coating designs available on request.
Harder than BK7, requires diamond tooling. Slower machining speed due to high hardness.
Good polishability but slower process than BK7. Achieves excellent UV-grade surface finish.
Excellent chemical resistance and UV stability. Virtually unaffected by moisture and most solvents.
Moderate cost, available in large ingots. Higher than BK7 but justified by superior UV and thermal performance.
No single optical material is perfect for every application. Here are situations where UV Fused Silica may not be the best fit, and what to consider instead.
→ Consider: Germanium, Zinc Selenide, or Zinc Sulfide
Fused silica absorbs strongly beyond ~2.1μm. For mid-IR and long-wave IR work, germanium or ZnSe are better suited.
→ Consider: BK7 or Sapphire
Fused silica has a relatively low refractive index (~1.458). If you need higher optical power in a thinner element, BK7 or sapphire offer higher n values.
→ Consider: BK7
Fused silica costs more than BK7. For standard visible-light systems where UV transmission isn't required, BK7 is more economical.
→ Consider: Sapphire
While fused silica is durable, sapphire (Mohs 9) is significantly harder and more scratch-resistant for harsh environments.
Browse our catalog of precision optical components available in UV Fused Silica
Consider BK7 if cost is a priority and UV transmission is not required. Consider sapphire if hardness and scratch resistance are the primary concern. Fused silica is the best choice when UV transparency, low thermal expansion or laser damage resistance are critical.
Send us your specifications. Our engineering team will review and respond with material and coating recommendations within 24 hours.
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