A dielectric mirror is a type of mirror based on multiple thin layers of different transparent optical materials (dielectric coatings, thin film coatings, interference coating). By choosing the type and thickness of dielectric layers, you can designate an optical coating with targeted reflectivity at various wavelengths of light. In addition, dielectric mirrors are also applied to produce ultra-high reflectivity mirrors. These mirrors provide higher reflectivity over a broad spectral range of up to a few hundred nanometers with longer lifetimes. The dielectric coating is comparably more enduring making the cleaning process easier and more resistant to laser damage.