07 Jul 2025 MgF2 (Magnesium Fluoride) transmits over a extremely wide range of wavelengths. Windows, lenses and prisms made of MgF2 can be used over the entire range of wavelengths from 0.12μm(vacuum ultraviolet ) to 8.0μm (infrared). High quality synthetic VUV grade MgF2 is quite expensive.
Low grade MgF2 is sometimes used in the infrared but it is inferior to CaF2. MgF2 is tough and works and polishes well, but it is slightly birefringent and should be cut with the optic axis perpendicular to the plane of the window or lens. | 
