MgF2 Windows are made from Magnesium Fluoride material, which has transparent range from 120-7000 nm. The refractive index is 1.376 at 7000nm.

Specifications:
Material: --------------------------------------------------------- Magnesium Fluoride single crystal
Diameter Tolerance: ------------------------------------------ +0.0, -0.1mm
Thickness Tolerance:------------------------------------------ ±0.2mm
Clear Aperture: ------------------------------------------------->80%
Parallelism:------------------------------------------------------- 1 arc minute
Flatness:----------------------------------------------------------- λ/2 @ 632.8 nm
Surface quality: ------------------------------------------------- 40/20 scratch and dig
Protective Bevel:--------------------------------------------------<0.25x45deg
Coating:-------------------------------------------------------------Uncoated