Specifications:
Materials | CVD ZnS crystals, IR grade or Cleartran grade | Diameter Range | ~ 250mm |
Aperture | >90% | Dimension Tolerance | +0.0/-0.2mm |
Thickness Tolerance | +/-0.1mm | Surface Quality | 60/40 S/D |
Parallelism | 1 arc minute | Chamfer | 0.3-0.5mmx45degree |
Coating | AR/AR coating@7-14μm |
Physical and Optical Properties:
Transmission Range | 0.37 to 13.5 μm | Refractive Index | 2.20084 at 10 μm |
Reflection Loss | 24.7% at 10 μm (2 surfaces) | Absorption Coefficient | 0.0006 cm-1 at 3.8 μm |
Reststrahlen Peak | 30.5 μm | dn/dT | +38.7 x 10-6 /°C at 3.39 μm |
dn/dμ = 0 | n/a | Density | 4.09 g/cc |
Melting Point | 1827°C (See notes below) | Thermal Conductivity | 27.2 W m-1 K-1 at 298K |
Thermal Expansion | 6.5 x 10-6 /°C at 273K | Hardness | Knoop 160 with 50g indenter |
Specific Heat Capacity | 515 J Kg-1 K-1 | Dielectric Constant | 88 |
Youngs Modulus (E) | 74.5 GPa | Shear Modulus (G) | n/a |
Bulk Modulus (K) | n/a | Elastic Coefficients | Not Avalailable |
Apparent Elastic Limit | 68.9 MPa (10,000 psi) | Poisson Ratio | 0.28 |
Solubility | 65 x 10-6 g/100g water | Molecular Weight | 97.43 |
Class/Structure | HIP poly-crystalline cubic, ZnS, F42m |
ZnS or Zinc Sulphide crystals grown by chemical vapor deposition (or CVD) exhibits exceptional fracture strength and hardness leading to its frequent choice for military applications or other harsh environments. This material is often used in the LWIR 7 to 14 microns region of thermal imaging. Its high resistance to rain erosion and high-speed dust and particulate abrasion makes it particularly suitable for exterior IR windows on aircraft frames.
Hangzhou Shalom EO provides the ZnS windows of IR grade and Cleartran or multi-spectrum grade materials, the AR/AR coating is made to increase the transmission of the windows.
Curves:
1.Transmission curve of the ZnS windows with AR/AR Coating
2.Transmission at visible wavelength range