ISP Optics’ BF-WW series of Barium Fluoride (BaF2) 30 min infrared wedged windows or infrared wedges is available with diameters ranging from 12.7 to 50.8 mm and a diameter tolerance of +0/-0.13 mm. Thickness of this series ranges from 2.0 to 6.0 mm, with a thickness tolerance of ±0.13 mm. The angle of these infrared wedged windows is 30 arcmin or 0.5°, with an angle tolerance of ±15 arcmin.
Barium Fluoride (BaF2) is an optical material that shows good optical transmission in the visible domain, but also in UV, SWIR and MWIR ranges. Transmission is higher than 90% from about 250 nm up to approximately 9,000 nm. This low refractive index material is diamond-turnable and can be mono- or poly-crystalline. Available sizes are slightly smaller than CaF2, while the material is more expensive.
Barium Fluoride is soft and brittle, its mechanical strength is 30% lower than that of Calcium Fluoride. Also, BaF2 shows very low thermal stability – in fact BaF2 has the lowest thermal stability of all infrared materials and crystals. It is susceptible to thermal shock, this is the single biggest problem with this material.