The 10Z40AL.2 Broadband Metallic Mirror is an excellent general purpose, broadband reflectors. This 1 inch (25.4 mm) diameter mirror is made from a 6.0 mm thick Zerodur substrate. Zerodur is a glass-ceramic material where thermal expansion is nominally zero. This extra stability can be critical for applications requiring diffraction limited performance. The AL.2 UV enhanced aluminum coating is a durable, broadband UV reflector with average reflectivity greater than 90% from 250–600 nm. The aluminum film is overcoated with UV transparent magnesium fluoride to prevent oxidation of the metal. This mirror has a λ/20 surface flatness and a 10-2 surface quality.