Magnesium fluoride (MgF2) is a material with a transparency in the wavelength range between 0.12 µm and 7.5 µm. It is also birefringent. The combination of these two properties enables the production of polarizing optics. Even at a wavelength of 121 nm, magnesium fluoride still has a transmission of 50 % (see spectral properties). Magnesium fluoride is characterized by its hardness and is used for robust and durable components. The material is also resistant to thermal and mechanical shocks. IMPEX uses the crystal growth methods of Czochralski and Bridgman to produce high-quality _MgF2 optics. The magnesium fluoride is available in both monocrystalline and polycrystalline form.

Magnesium fluoride is used to produce VUV optics (for space technology), polarization optics as well as windows and prisms for excimer lasers. It is also used for the lenses of medical microscopes