Spectralon

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.

[5] The material consists of PTFE powder that has been compressed into solid forms and sintered for stability, with approximately 40 percent void volume[clarification needed] to enhance scattering of light.

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.

[citation needed] The material shows no sign of optical or physical degradation after long-term immersion testing in sea water.

Optical-grade Spectralon has a high reflectance and Lambertian behavior and is used primarily as a reference standard or target for calibration of spectrophotometers.

Laser-grade Spectralon offers the same physical characteristics as optical-grade material but is a different formulation of resin that gives enhanced performance when used in laser pump cavities.