Spectralon

thumb|A Spectralon panel Spectralon is a fluoropolymer that has the highest diffuse reflectance of any known material or coating over the ultraviolet, visible, and near-infrared regions of the spectrum. It is the whitest substance available and reflects 99% of the light. It exhibits highly Lambertian behavior, and can be machined into a wide variety of shapes for the construction of optical components such as calibration targets, integrating spheres, and optical pump cavities for lasers.

== Characteristics == thumb|300px|Reflectance spectrum of Spectralon Spectralon's reflectance generally exceeds 99 percent over a range from 400 to 1500 nm and 95 percent from 250 to 2500 nm; however, grades are available with added carbon to achieve various gray levels. The material consists of PTFE powder that has been compressed into solid forms and sintered for stability, with approximately 40 percent void volume to enhance scattering of light. Surface or subsurface contamination may lower the reflectance at the extreme upper and lower ends of the spectral range. The material is also highly Lambertian at wavelengths from 257 nm to 10,600 nm, although reflectivity decreases at wavelengths beyond the near infrared. Spectralon exhibits absorbances at 2800 nm, then absorbs strongly (less than 20 percent reflectance) from 5400 to 8000 nm. Although the high diffuse reflectance allows efficient laser pumping, the material has a fairly low damage threshold of four joules per square centimeter, limiting its use to lower-powered systems.