Silver Mirror, Economy, Borofloat, 50.8 mm, λ/10, 480-20,000 nm

The 20D620ER.2 is an Economy Broadband Silver 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.2 silver coating. Borofloat® 33 has low thermal expansion and is an excellent substrate for most applications. Our ER.2 protected silver coating is composed of a low emissivity silver film fully encapsulated by a multilayer dielectric stack to prevent oxidation. This coating has excellent broadband reflectivity in the IR, while maintaining very good performance in the visible and near IR. The 20D620ER.2 has an average reflectivity greater than 96% from 480–1100 nm and greater than 98.5% from 1.1–20 μm. This mirror has a λ/10 surface flatness and a 40-20 surface quality.