Newport MKS Silver Mirror, Zerodur, 101.6 mm, λ/10, 480-20,000 nm 40Z20ER.2

The 40Z20ER.2 Broadband Silver Mirror is an excellent general purpose, broadband reflector. This 101.6 mm (4.0 inch) diameter mirror is made from a 17.7 mm thick Zerodur substrate. Zerodur, a glass-ceramic material, exhibits nominally zero thermal expansion which provides extra stability for applications requiring diffraction limited performance. The 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 40Z20ER.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 20-10 surface quality.