|Materials||Sapphire crystals||Diameter Range||Max. 300mm|
|Thickness Tolerance||+/-0.1mm||Surface Quality||Optional: 60/40, 40/20 or 20/10 S/D|
|Parallelism||30 arc sec||Chamfer||0.3-0.5mmx45°|
|Coating||No coating, or single layer MgF2 and other custom coating options|
|Transmission Range||0.17 to 5.5 μm||Refractive Index||No 1.75449; Ne 1.74663 at 1.06 μm|
|Reflection Loss||14% at 1.06 μm||Absorption Coefficient||0.3 x 10-3 cm-1 at 2.4 μm|
|Reststrahlen Peak||13.5 μm||dn/dT||13.1 x 10-6 at 0.546 μm|
|dn/dμ = 0||1.5 μm||Density||3.97 g/cc|
|Melting Point||2040°C||Thermal Conductivity||27.21 W m-1 K-1 at 300K|
|Hardness||Knoop 2000 with 2000g indenter||Specific Heat Capacity||763 J Kg-1 K-1 at 293K (4)|
|Dielectric Constant||11.5 (para) 9.4 (perp)at 1MHz||Youngs Modulus (E)||335 GPa|
|Shear Modulus (G)||148.1 GPa||Bulk Modulus (K)||240 GPa|
|Elastic Coefficients||C11=496 C12=164 C13=115 C33=498 C44=148||Apparent Elastic Limit||300 MPa (45,000 psi)|
|Poisson Ratio||0.25||Solubility||98 x 10-6 g/100g water|
|Molecular Weight||101.96||Class/Structure||Trigonal (hex), R3c|
Single Crystals Sapphire (Al2O3) Windows, featuring broad optical transmission from 150-5500nm spanning from UV to MWIR spectrum, and robust mechanical/thermal properties, are excellent for applications involving harsh and variant environments, or requiring a broad transparent wavelength range (e.g. windows of sensors and detectors, IR applications, etc.).
The material's most distinguishing attribute is its unequaled mechanical strength, being the second hardest material after diamond, single sapphire crystals have a Knoop Hardness of 1800-2200, making the windows made from single crystals sapphire extremely resistant to chemical corrosion and abrasions. Sapphire windows might be produced into thin optics without fracturing because of the tight internal covalent bonding of single crystal sapphire while demonstrating good thermal stability due to its high thermal conductivity.
Shalom EO offers various forms of Optical Sapphire Windows including flat windows with parallel faces, rectangular windows, wedge windows, and other custom specifications. Large aperture sapphire windows with diameters up to 300mm are available, and surface qualities of 60/40, 40/20, 20/10 Scratch/Dig are optional according to the precision requirements of your interest. Conventionally our sapphire windows are z-cut in order to prevent birefringence.
Shalom EO’s blank sapphire substrates are highly transparent in the wavelength range between 2.5-4.5µm with an average transmission rate above 85%. Single-layer MgF2 coatings and other AR coatings could be furnished to increase transmission. Precision sapphire windows requisite for laser systems are also procurable upon request. Additionally, Shalom EO provides a wide assortment of Optical Windows and Infrared Windows made from UVFS, NK7, Germanium, ZnSe, Silicon, etc.
Transmission curve of the Sapphire windows (no coating)