CaF2 Windows are made from Calcium Fluoride material, which has transparent range from 170-7800nm. The refractive index is 1.399 at 5000nm. It has little hygroscopic susceptibility and high thermal expansion coefficient. CaF2 Windows are relatively soft and somewhat hygroscopic so polishing, coating and handling are more critical than UV Fused Silica windows.

Specifications:
Material: --------------------------------------------------------- Calcium 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: ------------------------------------------------- 80/50 for general and 40/20 scratch and dig  for high precision

Protective Bevel:--------------------------------------------------<0.25x45deg

Coating:-------------------------------------------------------------Uncoated