Zinc Sulfide is an inorganic compound with the chemical formula ZnS. It is a white or yellowish powder that darkens when seen in light. Stable in dry air, for a long time in wet air or containing moisture, gradual oxidation to zinc sulfate.

The research of zinc sulfide fluorescent material has a history of more than 130 years since it was discovered by French chemist Sidot in 1868. The research of zinc sulfide material has been concerned by people from 1920s to 1940s.

Zinc sulfide (ZnS) is widely used in making infrared Windows, fairings and infrared optical elements. It has the characteristics of high purity, insoluble in water, moderate density and easy to process. Zinc sulfide (ZnS) has good refractive index uniformity and good image transmission performance in the band range of 8-12μm, but after 10um part of absorption. In the middle infrared band, the transmittance is higher, and the absorption and scattering are enhanced along with the shorter wavelength. Zinc sulfide (ZnS) has strong resistance to harsh environment, high hardness and fracture strength is twice that of Zinc Selenide (ZnSe). Tough front optics for zinc sulfide (ZnS) thermal imaging systems for infrared Windows and thermal bands (8 to 14μm). Single crystal zinc sulfide (ZnS) is available but not common. The scattering is very low in the usual spectral range. It can be used as a high-power laser device by strictly controlling the bulk absorption and internal structural defects of the material, using the Chemicalbook polishing technology with the minimum damage degree and the coating process with the highest optical quality. Zinc sulfide (ZnS) oxidizes significantly at 300℃, exhibits plastic deformation at about 500℃, and dissociates at about 700℃. For safety reasons, zinc sulfide Windows should not be used above 250°C in normal atmosphere.