Manufacturers of optical coatings and components

Reflectance of various bare metals vs. wavelength

[green: silver (Ag), blue: aluminum (Al), yellow: gold (Au), blue-green: copper (Cu), black: rhodium (Rh), red: platinum (Pt), purple: nickel (Ni)]

Newport Thin Film Laboratory produces a wide variety of metal mirrors, a few of the more common types of which are plotted above.  Note that the graph above is for bare metal coatings, which are relatively delicate and require care during cleaning and handling.   Any metal coating can be overcoated with dielectric layers that substantially improve abrasion resistance and protect against oxidation.  Generally, metals protected by a single dielectric layer are termed protected metal films and metals protected by multiple dielectric layers are termed enhanced metal films.  Enhanced metal films are designed to increase the reflectance over a particular wavelength region versus the bare metals.