Zinc Selenide (ZnSe)


Zinc Selenide (ZnSe)

Zinc Selenide is a light-yellow, solid compound comprising zinc and selenium. It is created by synthesis of Zinc vapour and H2 Se gas, forming as sheets on a graphite substrate. ZnSe has an index of refraction of 2.403 at 10.6 µm, due to its excellent imaging characteristics, low absorption coefficient and high resistance to thermal shock, it is commonly used in optical systems that combine CO2 laser (operating at 10.6 μm) with inexpensive HeNe alignment lasers. However, it is quite soft and will scratch easily. Its transmission range of 0.6-16 µm makes it ideal for IR components (windows and lenses) & for spectroscopic ATR prisms, and widely used in thermal imaging systems. ZnSe also transmits some visible light and has low absorption in the red portion of the visible spectrum, unlike germanium and silicon, thereby allowing for visual optical alignment.

Zinc Selenide oxidizes significantly at 300℃, exhibits plastic deformation at about 500℃ and dissociates about 700℃. For safety, ZnSe windows should not be used above 250℃ in normal atmosphere.

Material Properties

Refractive Index

2.403 @10.6 µm

Abbe Number (Vd)

Not Defined

Thermal Expansion Coefficient (CTE)

7.1x10-6/℃ at 273K



Transmission Regions & Applications

Optimum Transmission Range Ideal Applications
0.6 - 16 μm
8-12 μm AR coating available
Transparent in the visible spectrum
CO2 lasers and thermometry and spectroscopy, lenses, windows, and FLIR systems
Visual optical alignment


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

Tips: When working with Zinc Selenide, one should always wear gloves, this is because the material is hazardous. For your safety, please follow all proper precautions, including wearing gloves when handling this material and thoroughly washing your hands afterward.


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