Sapphire (Al2O3) is the hardest oxide crystal, has a combination of perfect optical and physical properties that make it the best choice for some demanding applications. LNG Optics focus on optical applications only, offer custom made windows and other optical components.
Main properties of Sapphire crystal:
Transparency Range: 170-5500nm
Absorption Coefficient: 0.3×10-3/cm @ 2.4μm
Refractive Indices (no): 1.83 @ 260nm, 1.76 @ 633nm, 1.63 @ 5000nm
Crystal Structure:Hexagonal
Lattice Constant: a=4.785Å, c=12.991Å
Density: 3.98 gram/cm3
Mohs hardness: 9
Young's Modulus: 435 GPa
Melting Point: 2030℃
Thermal Conductivity: 40 W/m·K
Thermal Expansion Coef. @ 25℃: //C 5.6, ⊥C 5.0 (10-6/K)
Features & Standard Specifications from LNG Optics:
Diameter tolerance: +0/-0.1mm, Thickness tolerance: ±0.2mm
Surface quality: 60/40 S/D
Flatness: λ/4 @ 633nm
Transmission Wavefront Distortion: λ/4 per inch @ 633nm
Parallelism: 3 arc minutes
Perpendicularity: 5 arc minutes
Chamfer: 0.1mm x 45°
Lens, Prisms, Light pipes and AR, HR coated elements are available upon request.