Sapphire
- Al2O3
Sapphire (Al₂O₃) is an exceptionally durable optical material valued for its wide transmission range from the UV through visible and into the mid-infrared (typically 150 nm to 5.5 µm). Its extreme mechanical strength, high melting point, and outstanding chemical resistance make it ideal for demanding applications where optical clarity must be combined with maximum durability.
With a refractive index of ~1.76 at 589 nm and low absorption across the UV–IR range, sapphire delivers excellent imaging performance, high optical stability, and strong resistance to thermal shock. It is widely used in UV/visible optics, high-power laser systems, aerospace and defence components, industrial sensors, medical devices, and precision imaging systems.
Sapphire is non-hygroscopic, scratch-resistant, chemically inert, and capable of operating at very high temperatures, making it suitable for both harsh industrial environments and high-performance optical systems. Its extremely high laser-damage threshold and mechanical robustness also make it a preferred material for laser windows, protective viewports, domes, prisms, and IR imaging components.
Explore Related Optical Materials:
Fused Silica (SiO2)
Magnesium Fluoride (MgF2)
Calcium Fluoride (CaF2)
FAQ
FAQ
Q: What is Sapphire used for in optical applications?
A: Sapphire is widely used for laser windows, protective viewports, aerospace optics, high-temperature sensors, imaging systems, and rugged UV–IR optical components due to its extreme hardness and broad 0.20–5.5 µm transmission range.
Q: What makes Sapphire different from other optical materials?
A: Sapphire is one of the hardest optical materials available (Knoop ~2000), offering exceptional scratch resistance, high thermal conductivity, excellent UV–IR transmission, and outstanding durability in harsh or abrasive environments.
Q: Is Sapphire hygroscopic?
A: No. Sapphire is completely non-hygroscopic and remains stable in humid, wet, or outdoor environments.
Q: Is Sapphire suitable for high-power lasers?
A: Yes. Sapphire has a very high laser-damage threshold and excellent thermal stability, making it ideal for high-power UV, visible, and IR laser windows and beam-delivery systems.
Q: What optical components can be made from Sapphire?
A: Common sapphire components include windows, viewports, lenses, domes, protective covers, IR sensor windows, and high-strength optical elements for defence, aerospace, and industrial systems.
Q: How durable is Sapphire compared to glass or fluoride crystals?
A: Sapphire is significantly harder and more scratch-resistant than quartz, MgF₂, CaF₂, ZnSe, and other infrared materials. It excels in abrasive, high-temperature, high-pressure, or chemically demanding environments.
Q: Can Sapphire optics be anti-reflection coated?
A: Yes. Sapphire can be supplied uncoated or with UV, visible, or IR AR coatings, as well as DLC (diamond-like carbon) for extreme durability.
Q: Is Sapphire safe and easy to handle?
A: Yes. Sapphire is non-toxic and chemically inert. Its extreme hardness prevents surface damage, but care should still be taken to avoid edge chipping.
Q: Where can I obtain technical data for Sapphire?
A: Full sapphire datasheets, specifications, and optical graphs are available here at Global Optics UK.