Advantages of Calcium Fluoride – CaF2 lenses and windows

Calcium Fluoride (CaF2) can be used for optical windows, lenses, prisms and blanks in the Ultraviolet to Infrared region. It is a relatively hard material, being twice as hard as Barium Fluoride.  Calcium Fluoride material for Infra-red use is grown using naturally mined fluorite, in large quantities at a relatively low cost. Chemically prepared raw material is usually used for UV applications.

It has a very low refractive index which allows it to be used without an anti reflective coating. Calcium Fluoride windows with polished surfaces are stable and will last several years under normal conditions until temperatures rise to 600°C when it starts to soften. In dry conditions it has maximum operating temperature of 800°C. Calcium Fluoride windows can be used as a laser crystal or radiation detection crystal by doping it with the appropriate rare earth elements. It is a chemically and physically stable crystal with excellent water resistant, chemical resistant and heat resistant characteristics. It offers low absorption and high transmission ranging from Vacuum Ultraviolet 125nm to Infra-red 8 microns. Its unique optical dispersion mean it can be used as an achromatic lens combined with other optical materials.

All of these properties encourage a wide use in astronomy, photography, microscopy, HDTV optics and medical laser instruments. Calcium Fluoride windows can be manufactured from vacuum ultraviolet grade Calcium Fluoride which are commonly found in cryogenically cooled thermal imaging systems. As it is physically stable and chemically inert with superior hardness, it is the choice material for microlithography and laser optics applications. Achromatic Calcium Fluoride lenses can be used in both cameras and telescopes to reduce light dispersion and in the oil and gas industry as a component in detectors and spectrometers.

Post time: Aug-02-2021