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CleartranTM
(ZnS, Multi-Spectral)
Cleartran is a water-free form of Zinc Sulfide. A Chemically Vapor Deposited (CVD) material , multi-spectral ZnS has low absorption and scatter properties over its relatively broad transmission range. Due to its good transmission in the visible and infrared, ZnS multi-spectral grade is an ideal choice for systems utilizing a visible camera, and various infrared detectors or an infrared camera in the infrared region. It is about one third harder than ZnSe and about 2/3 the hardness of ZnS, regular. The cost is about 1/3 more than ZnS regular and about the same as ZnSe. This type of ZnS does not have absorption in the 6µm region as found in regular CVD-type material. It is also a good choice for IR-visible systems.
| Property |
Specification |
| Transmission Range |
0.4µm to 12µm |
| Density |
4.09
g/cm3 |
| Thermal
Expansion |
6.3 x 10-6 /°K @ 273°K, 7 x 10-6/°K @ 373°K & 7.5 x 10-6/°K @ 473°K |
| Surface Finish |
Typical specifications for surface quality in the 0.4 - 3µm spectral region is 40-20 scratch-dig & in the 3 - 12µm spectral region is 60-40 or 80-50. Diamond turned surface roughness of 150 Å rms or better are typical. |
| Surface Figure |
In the infrared, typical required surface figure ranges from 1/2 to 2 waves @ 0.6328µm depending on the system performance requirements. |
| AR Coating Options |
Typical available coatings for ZnS multi-spectral grade include a BBAR for the 3 to 5µm band & a BBAR for the 8 to 12µm band. Many other specialized wavelength bands are possible within the 0.4 to 12µm range. |
| Typical Applications |
Thermal imaging, FLIR, Astronomical. |
| Products Manufactured |
Lenses, Aspheric lenses, Binary (Diffractive) Lenses, Windows, Optical Beamsplitters, Filters, Prisms. |
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Wavelength (µm)
|
Index of Refraction (n)
|
|
4.2
|
2.244
|
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6.2
|
2.238
|
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8.2
|
2.221
|
|
10.2
|
2.198
|
|
12.2
|
2.167
|
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14.2
|
2.126
|
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