Barium Fluoride (BaF2) is transparent from the UV to the IR (200 nm - 11um) and has an index of refraction of 1.468 at 1.064um. Barium fluoride's properties are similar to those of calcium fluoride, but it is more resistant to high-energy radiation. It is, however, less resistant to water damage. Pronounced degradation of the BaF2 substrate occurs at 500 ??C when exposed to water, but in dry environments, it can be used in applications requiring exposure to temperatures up to 800 ??C.
Plano-Convex lenses have a positive focal length and approach best form for infinite and finite conjugate applications. These lenses focus a collimated beam to the back focus and collimate light from a point source. They are designed with minimal spherical aberration and have a focal length given by: f= R/(n-1), where R is the radius of curvature of the convex portion of the lens and n is the index of refraction. To minimize the introduction of spherical aberration, a collimated light source should be incident on the curved surface of the lens when being focused and a point light source should be incident on the planar surface when being collimated.