| Windows Type | Circular, rectangular and other special shape windows | Materials | Optical grade single crystal sapphire |
| Aperture | >90% | Dimension Tolerance | +0.0/-0.2mm |
| Thickness Tolerance | +/-0.2mm | Flatness | customized |
| Surface Quality | Option: 60/40, 40/20 or 20/10 S/D | Parallelism | 1 arc minute |
Physical and optical properties:
| Transmission Range | 0.17 to 5.5 μm | Refractive Index | No 1.75449; Ne 1.74663 @ 1.06 μm |
| Reflection Loss | 14% at 1.06 μm | Absorption Coefficient | 0.3 x 10-3 cm-1 @ 2.4 μm |
| Reststrahlen Peak | 13.5 μm | dn/dT | 13.1 x 10-6 @ 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 @300K |
| Thermal Expansion | 5.6 (para) & 5.0 (perp) x 10-6 /K * | Hardness | Knoop 2000 with 2000g indenter |
| Specific Heat Capacity | 763 J Kg-1 K-1 @ 293K | Dielectric Constant | 11.5 (para) 9.4 (perp) @ 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 |
Sapphire Windows are manufactured from single crystal sapphire, making them ideal for demanding applications (such as laser systems) because of their extreme surface hardness, high thermal conductivity, high dielectric constant and resistance to common chemical acids and alkalis. Sapphire is the second hardest crystal next to diamonds and, because of their structural strength, sapphire windows can be made much thinner than other common dielectric windows with improved transmittance. Chemically, sapphire is single crystal aluminum oxide (Al2O3) and is useful in a transmission range from 0.2 - 5.5μm. Customized windows are offered upon customer’s request.
Curves:
Transmission of Sapphire Windows without Coating at UV to 1100nm
Transmission of Sapphire Windows without Coating at 2.5μm to 8.0μm
