(Multi-spectrual) Zinc Sulfide (ZnS)


(Multi-spectrual) Zinc Sulfide (ZnS)

Zinc Sulfide is produced by synthesis from Zinc vapour and H2S gas, forming as sheets on Graphite susceptors. It is microcrystalline in structure, the grain size being controlled to produce maximum strength. ZnS transmits well in the IR and visible spectrum, it is an excellent choice for thermal imaging. ZnS is harder, structurally stronger and more chemically resistant than ZnSe, it is typically a cost effective choice over other IR materials. Multi-spectral grade is then Hot Isostatically Pressed (HIP) to improve the mid IR transmission and produce the visibly clear form. Single crystal ZnS is available, but is not common. Multi-spectral ZnS (water-clear) is used for IR windows and lenses in the thermal band of 8 - 14 μm where maximum transmission and lowest absorption is required. Also it is selected for use where visible alignment is an advantage.

Material Properties

Refractive Index

2.201 @ 10.6 µm

Abbe Number (Vd)

Not Defined

Thermal Expansion Coefficient (CTE)

6.5 x 10-6 /℃ at 273K



Transmission Regions & Applications

Optimum Transmission Range Ideal Applications
0.5 - 14 μm Visible and mid-wave or long-wave infrared sensors, thermal imaging


The right graph is transmission curve of 10 mm thick, uncoated ZnS substrate

Tips: Zinc Sulphide oxidizes significantly at 300°C, exhibits plastic deformation at about 500°C and dissociates about 700°C. For safety, Zinc Sulphide windows should not be used above 250°C in normal


For more in-depth specification data, please view our catalog optics to see our complete selection of optics made from zinc sulfide.