A dielectric mirror, also known as a Bragg mirror, is a type of mirror composed of multiple thin layers of dielectric material, typically deposited on a substrate of glass or some other optical material. By careful choice of the type and thickness of the dielectric layers, one can design an optical coating with specified reflectivity at different wavelengths of light.

Since Dielectric coatings are thin-film coatings made of transparent dielectric materials, e.g. for laser mirrors or anti-reflection coatings. While simple single-layer coatings are often used as anti-reflection coatings, dielectric mirrors normally use dozens of thin-film layers, sometimes even more than 100. The most common dielectric materials used for dielectric mirrors are metal oxides such as titanium dioxide (TiO2), silicon dioxide (SiO2), and tantalum pentoxide (Ta2O5).