Spectralon
Spectralon is a material made of sintered PTFE, which has a very high and uniform reflectivity in both the ultraviolet ( UV) as has also in the visible ( VIS) and near infrared (NIR) region of the electromagnetic spectrum. It shows lambert cal reflection behavior, that reflects very diffuse or matte. It is used in various forms in optical components, eg as a reflectance standard in calibration patterns, integrating spheres and lasers.
Properties
The hardness is comparable to high density polyethylene ( HDPE ). It is thermally stable up to about 350 ° C. The material is chemically inert to many bases except very strong, such as sodium amide or lithium compounds. It is extremely hydrophobic, but absorbs non-polar solvents, greases and oils.
Material impurities can be removed only with difficulty, therefore, the material should be treated with care as possible. Minor impurities or scratches on the surface can be removed with sand under a jet of water. The reflection properties can be largely restored. Studies on weathering show that no damage due to atmospheric UV radiation occur and no optical or physical damage during prolonged storage in salt water. The reflectance of Spectralon is usually above 99% in the wavelength range 400-1500 nm and over 95% of 250-2500 nm Spectralon is also available in graduated shades of gray with a defined lower reflectivity. The material contains a proportion of carbon. The material shows a strong lambert cal reflection behavior in the range 257-10600 nm, where the reflectance is greatly reduced at wavelengths above the near infrared. Spectralon absorbing in the region of 2800 nm and 5400 to 8000 nm, the reflectance here is less than 20 %. The material has a damage threshold of 4 joules per square centimeter. Therefore, it can be used only for low power applications.
Lambert's reflection characteristics caused by the structure of the surface and directly below it. A porous network of molecular chains produced multiple internal reflections within the first tenth of a millimeter below the surface. This reflects incident light diffusely. Spectralon light can partially depolarize, but this effect is reduced .. at large angle of incidence
Applications
Spectralon is available in three levels of quality: quality optical, laser and aerospace quality. Spectralon class optical quality is highly reflective and ideal diffuse. Laser quality class has the same physical properties, but is optimized for a different mix of materials for use in the optical pumping. It is used in various " side-pumped " lasers. Spectralon, which was classified with aerospace - quality, is used in aerospace applications for remote sensing satellites.
History
Spectralon has been marketed since 1986 by Labsphere.