Manufacturers of optical coatings and components

Reflectance of protected aluminum at normal incidence

Aluminum is the most widely used metal for reflecting films, having good reflectivity throughout the UV, visible and IR regions.  Aluminum coatings are susceptible to oxidation, which reduces the UV reflectance and causes scattering throughout the spectrum.  Therefore, aluminum films are typically protected by one or more dielectric films.

Protected aluminum films incorporate a single dielectric layer of an oxide material that helps prevent oxidation.   Protected aluminum is an excellent first or second surface general purpose mirror that can stand up to mild cleaning.