OST Photonics Al2O3 Crystals (Sapphire)

OST Photonics Al2O3 Crystals (Sapphire)
Al2O3 crystals (Sapphire), 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 resistant in extreme to chemical corrosion and abrasions. Custom 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 stabilities due to its high thermal conduction.

Application of Al2O3 Crystals (Sapphire)

Infrared windows

LED lighting

Semiconductor device

Advantages of Al2O3 Crystals (Sapphire)

Features Extreme Surface Hardness Chemical Resistance

Transmits Wavelengths Ranging From UV to Mid-Infrared

Thinner and Stronger than Standard Glass Windows

Specifications of Al2O3 Crystals (Sapphire)

Orientation Random or as requested
Size Upon the customer’s request
Diameter Tolerance +0/-0.1 mm
Thickness Tolerance +/-0.1 mm
Aperture >90%
Surface Quality 60/40~10/5 (S/D)
Parallelism <1 arc minute
Chamfer 0.2-0.5mmx45®
Coating Uncoated or upon customer’s request

Properties of Al2O3 Crystals (Sapphire)

Transmission Range 0.17 to 5.5 microns
Refractive Index No 1.75449; Ne 1.74663 at 1.06 micron
Refractive Loss 14% at 1.06 micron
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
Crystal/Class Structure Trigonal (hex), R3c
Molecular Weight 101.96
Cleavage Plane (1011), (1012), imperfect
Density 3.97 g/cc
Melting Point 2040®C
Hardness (Knoop) 2000 with 2000g indenter
Youngs Modulus 335 GPa
Shear Modulus 148.1 GPa
Bulk  Modulus 240 GPa
Poisson Ratio 0.25
Elastic Limit 300Mpa (45.000psi)
Thermal Conductivity 27.21 W m-1 K-1 at 300K
Specific Heat Capacity 763 J Kg-1K-1 at 293K (4)
Dielectric Constant 11.5 (para) 9.4 (perp) at 1MHz
Elastic Coefficients C11=496 C12=164 C13=115 C33=498 C44=148
Solubility 98 x 10^-6 g/100g water.