ZNSE

 Zinc Selenide,(ZnSe) a chemically vapor deposited material, is the material of choice for optics used in high power CO₂ laser systems due to its low absorption at 10.6µm. However it is also a popular choice in systems operating at various bands within its wide transmission range. ZnSe has a high resistance to thermal shock making it the prime material for high power CO₂ laser systems. ZnSe however is only 2/3 the hardness of ZnS multi-spectral grade but the harder anti-reflectance coatings do serve to protect ZnSe. Zinc Selenide’s cost is about the same as ZnS multi-spectral grade and is generally more expensive than Germanium.