Many different types of material will transmit the infra-red. Selection of the most appropriate material is usually made with reference to the extent of the required transmittance and the nature of the environments being isolated by the window.

Zinc Selenide (ZnSe), Zinc Sulphide (ZnS), Germanium (Ge) or Gallium Arsenide (GeAs) are commonly used for the broad IR spectrum including both 3-5μm and 8-14μm bands.

Calcium Fluoride and Magnesium Fluoride are used in the 3-5 μm band while maintaining high transmittance in the visible. Here are some of the commonly available materials:

Material	Transmission Range (μm)
ZnSe	0.68~18.0
ZnS	0.38~14.0
Ge	1.90~16.0
Si	1.20~7.00
CaF2	0.17~7.80
MgF2	0.13~7.00

Typical diameters offered are: 6.35, 10.0, 12.7, 25.4, 38.1, 50.8, 76.3 and 200mm.

Thickness varies from 1.0 to 6.0 mm as appropriate to maintain the flatness specification.

These windows are normally supplied uncoated but we can.