The use of dielectric and thus absorption-free coatings allows the production of mirrors with reflexions greater 99 %.

The reflexion measurement of extremely high reflexion values and with different angles of incidence 0...60° makes only sense if the absolute measurement ("VW" measuring principle) is used. These measurements were carried out on the inhouse Lambda 950 with URA.

Metallic mirrors consist of the high reflective materials aluminium, silver or gold, which are evaporated via latest technology with high vacuum to the carrier material, which generally consists of glass or ceramics.
The optical characteristics of metallic mirrors are constant in a wide spectral range. They are only marginally dependent on the angle of incident and have only a low polarising effect. However, the application areas are limited by the considerable absorption, which has, compared to dielectric layers, a lower hardness and a higher susceptibility to chemical influences.