Optical coatings made of metals sometimes have considerable absorption losses. For this reason, the reflection is too low for many technical applications. For highly reflective mirrors, therefore, dielectric coatings are used exclusively. These transmit the non-reflected part and can thus achieve very low absorption values.
Such coating systems are optimized for one wavelength or laser and thus achieve reflection values of up to 99.9 %. The coating of glass enables the production of mirrors for one or two wavelengths and even for broadband applications. Such High-Power coatings are optimized for High-Power laser applications.