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.

 

Wavelength (µm)
Index of Refraction (n)
4.2
2.244
6.2
2.238
8.2
2.221
10.2
2.198
12.2
2.167
14.2
2.126