Zinc selenide

Zinc selenide (ZnSe) optical windows are crucial components in a variety of imaging and laser systems due to their exceptional properties. These windows offer excellent transparency in the infrared (IR) spectrum, particularly from 0.5 μm to 22 μm.

They boast low dispersion, making them suitable for a wide range of optical applications, and demonstrate remarkable chemical stability by not absorbing moisture from the air, thus remaining non-hygroscopic. However, it's important to handle ZnSe with care due to its softness, which is indicated by a Knoop number of 105, care should be taken to prevent scratching its surface.

In summary, ZnSe optical windows are vital for their outstanding IR transmission and chemical stability in various systems. To ensure their effective use, it's essential to adhere to proper handling practices. 

Optical Grade Zinc Selenide (ZnSe) is a widely used infrared material with the following technical properties:

Transmission Range: 0.6 to 21 μm

Refractive Index: 2.4028 at 10.6 μm

Reflection Loss: 29.1% at 10.6 μm (2 surfaces)

Absorption Coefficient:

0.0005 cm-1 @ 10.6 μm

0.0004 cm-1 @ 5.25 μm

0.0004 cm-1 @ 3.8 μm

0.0007 cm-1 @ 2.7 μm

0.005 cm-1 @ 1.3 μm

Reststrahlen Peak: 45.7 μm

dn/dT: +61 x 10-6/°C at 10.6 μm at 298K

Density: 5.27 g/cc

Melting Point: 1525°C

Thermal Conductivity: 18 W m-1 K-1 @ 298 K

Thermal Expansion: 7.1 x 10-6/°C @ 273 K

Hardness Knoop: 120 with 500g indenter

Specific Heat Capacity: 339 J Kg-1 K-1

Dielectric Constant: n/a

Young’s Modulus (E): 67.2 GPa

Shear Modulus (G): n/a

Bulk Modulus (K): 40 GPa

Elastic Coefficients: n/a

Apparent Elastic Limit: 55.1 MPa (8000psi)

Poisson Ratio: 0.28

Solubility: 0.001g/100g water

Molecular Weight: 144.33

Class/Structure: FCC Cubic, F43m (#216), Zinc Blende structure. (Polycrystalline)

Please note that these values are typical and may vary based on the grade and manufacturing process of the material