|
Zinc Sulfide (ZnS)
Zinc Sulfide (ZnS), Regular Grade. A Chemically Vapor Deposited (CVD) material, ZnS (regular) has good imaging quality over the 8-12µm band. It also transmits in the 3-5µm band, but with higher absorption and scatter. The material exhibits high strength and hardness, and good resistance to hostile environments. The ZnS regular is 50% harder than ZnS, multi-spectral grade and twice and hard as ZnSe. ZnS regular does not transmit well in the visible spectral region. It has the relatively low cost of about 2/3 the price of ZnS, multi-spectral grade or ZnSe. Zinc Sulfide is mainly used for windows and lenses in the 8µm to 12µm range. The reflective index is near 2.2. Zinc Sulfide is particularly strong and can be used for infrared windows in high speed aircraft and vacuum applications.
| Property |
Specification |
| Transmission Range |
3µm
to 12µm |
| Density |
4.09
g/cm3 |
| Thermal
Expansion |
6.6
x 10-6 /°K @ 273°K, 7.3 x 10-6/°K @ 173°K |
| Surface Finish |
Typical specifications for surface quality in the 3-12µm spectral region are 60-40, 80-50 or 120-80 scratch-dig depending upon system performance requirements. ZnS regular is diamond turnable. |
| Surface
Figure |
In the infrared, typical surface figure ranges from 1/2 wave to 2 waves @ 0.6328µm depending on the system performance requirements. |
| AR Coating Options |
Typical available coatings for ZnS include BBAR for the 3 to 5µm & the 8 to 12µm regions. Many other specialized wavelength bands are possible within the 3 to 12µm spectral range. |
| Typical
Applications |
Thermal
imaging, FLIR |
| Products
Manufactured |
Lenses, Aspheric lenses, Windows, Domes, Wedges. |
|
Wavelength (µm)
|
Index of Refraction (n)
|
|
1.0
|
2.292
|
|
3.0
|
2.257
|
|
5.0
|
2.246
|
|
7.0
|
2.232
|
|
9.0
|
2.212
|
|
11.0
|
2.186
|
|
13.0
|
2.152
|
|
15.0
|
2.106
|
|
17.0
|
2.045
|
|
