Gold Mirror, Economy, Borofloat, 50.8 mm, λ/10, 650-20,000 nm

The 20D620ER.4 is an Economy Broadband Gold Mirror. By taking advantage of advanced polishing techniques and our high-volume manufacturing, these mirrors are truly cost effective. This 50.8 mm (2.0 inch) diameter mirror is made from a 12.7 mm thick Borofloat® 33 substrate which is coated with the ER.4 gold coating. Borofloat® 33 has low thermal expansion and is an excellent substrate for most applications. The ER.4 protected gold coating is ideal for applications requiring broadband reflectance in the near IR to the far IR. A multilayer dielectric overcoat provides protection to the gold from the environment. The 20D620ER.4 has an average reflectivity greater than 96% from 650–1700 nm and greater than 98% from 1.7–20 μm. This mirror has a λ/10 surface flatness and a 40-20 surface quality.