Specifications:
| Materials | CVD ZnS Crystals, FLIR Grade or Cleartran | 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 |
Optical grade Zinc Sulfide is a synthetic component made from Chemical Vapour Deposition (CVD). However, normal CVD ZnS is opaque in the visible spectrum, this material is often used in the LWIR (7 to 14 micro) region of thermal imaging and sold under the name Forward Looking Infrared (FLIR) grade ZnS. There is also Multispectral ZnS (or Cleartran), which goes under a further post-deposition hot isostatic press process after the CVD fabrication, increasing the transmission rate to a single-crystal like altitude across the Visible to IR range (0.4-14.0μm). The hot press process eliminates the water composition of ZnS, therefore this material is also known as water-clear ZnS.
Hangzhou Shalom EO offers windows made from FLIR grade ZnS, and Multispectral (Cleartran) Zinc Sulfide. Various custom shapes and anti-flection coatings on two surfaces are available. The multispectral ZnS windows are exceptional for applications through out UV, VIS, and IR region (e.g. visible camera, mid-and long-wave detectors, and laser rangefinders). In comparison FLIR grade ZnS is harder, although both FLIR grade and Multispectral (Cleartran) Zinc Sulfide has higher mechanical strength than ZnSe and could adapt to applications under extreme conditions (e.g. exterior IR windows on aircraft frames).
Curves:
1.Transmission curve of the ZnS windows with AR/AR Coating
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2.Transmission at visible wavelength range
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