Esco provides a variety of flat mirror substrates. Standard items are supplied front surface-coated with aluminum (AI) overcoated with either silicon monoxide (SiO) or magnesium fluoride (MgF2). AI-SiO is an excellent all-purpose coating that provides greater than 85% average reflectance from 350-800 nm. For broadband ultraviolet-visible applications, AI-MgF2 provides greater than 85% average reflectance from 200-800 nm. For detailed information concerning the characteristics of optical coatings, see the coatings section, or Contact Esco.