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Sapphire(Al2O3) window

Sapphire(Al2O3) window

Sapphire(Al2O3) optical window


 Single crystal of Sapphire(Al2O3),  Purity: >99.995%

Other Names

Sapphire window substrate, Al2O3 window, Sapphire glass window

Crystal structure


Applicable wave band

0.2μm ~ 5.5μm

Refractive Index
(at 300K)

∥C,1.762 @630nm ⊥C,1.770 @630nm

Melting Point


Operating temperature


Refractive index

No 1.75449; Ne 1.74663 at 1.06 μm

Absorption coefficient

≤0.0003 /cm at 2.4μm
Thermal Conductivity

46.06 @ 0℃  25.12 @ 100℃,  12.56 @ 400℃ ( W/(m.K) )

Mohs hardness


Dielectric constant
(*103-109Hz @25℃)


Thermal expansion coefficient


Maximum size

 Diameter 220mm (Single crystal)
 Square 300mm (Single crystal)

Material Standard Size Surface quality
Sapphire(Al2O3) window φ12.7mm x 1.0mm
φ25.4mm x 3.0mm
φ25mm x 1.0mm
φ50mm x 3.0mm
φ100mm x 0.5mm
φ100mm x 1.0mm
φ100mm x 5.0mm
10 x 10 x 1.0mm
25.4 x 25.4 x 3.0mm
Or others
Polishing:             Double side optical-polished or Epi-polished
Roughness:          Ra<1.5nm or Ra 5~10nm, Ra<0.5nm, 
Size Tolerance:          +/-0.1mm
Thickness Tolerance: +/-0.1mm or +/-0.05mm
Parallelism:           1 minute, 30 seconds, 5 seconds or higher
Surface Finish:      60-40, 40-20, 20-10 (scratch-dig)
Surface Figure:      1/2λ, 1/4λ or higher
Chamfer:                0.25mm × 45°
Coating:                 Upon requirements

Sapphire (Al2O3) single crystal is an excellent optical window and substrate material. It has high temperature resistance, good thermal conductivity, high hardness, infrared transmission, and good chemical stability. Sapphire (Al2O3) window has high transmittance in the Ultraviolet, Visible and Infrared band, the transmission band range is 0.2-5.5um, its operating temperature can resistance at 1700 ℃, high hardness and second only to diamond, and resistance to acid and alkali corrosion.
Sapphire glass windows can be used as optical window lenses, lens protection external lenses, Isolation windows, armored windows, wear-resistant windows / optical components, high temperature and impact resistant optical windows, etc.

We can customize different size and thickness of Sapphire(Al2O3) optical window upon requirements, such as Sapphire(Al2O3) round wafer, Square substrate and Cylinder, or Punch holes and other shapes.

Contact Us

  • Tel: (+86) 1506 0796 451
  • Fax: (+86) 0597 2212602
  • Email:
  • Work Time ( GMT +8 ):
  •    9 AM ~ 6 PM, Monday to Friday
  • Main office: A7, No. 501, Denggaoxi Road, Xipi street, Xinluo District, Longyan, Fujian, China