Laser mirrors are used to form the optical path of lasers used for surveying and shape measurement. Dielectric multilayers are used for the reflective film to achieve high reflection at specific wavelengths.
Metallic films such as aluminum may be used, but due to metal absorption, only about 90% reflectance can be obtained, and the durability of the film itself is low, so a protective film is required on the surface. Dielectric mirrors have higher reflectivity and durability than metallic films.
Single wavelength to broadband applications are available.