Plate beamsplitters are thin plane-parallel or edge plates made of optical glass , quartz or singleaxis crystals (e.g. CaF2) coated with thin-film layers system. Depending on application it can be either metallic layer or dielectric coating. However
one should remember that such an element introduces a shift or deviation into the light beam due to the thickness of optical element. In order to get the normal deviation between transmitted and reflected beams the working angle of incidence should mainly be 45°. The second surface of optical element is often coated with antireflection coating to avoid unwanted additional reflections. Such a divider can be applied in optical systems with high power of light beam.