Antireflection coating for ultraviolet light at large angles of incidence

Abstract

Antireflection multilayer coatings with only three or four layers are proposed for the production of laser resistant optical components with minimal residual reflection and high transparency for UV light in a wavelength range approx. 150 nm to approx. 250 nm at large angles of incidence in the range of approx. 70° to approx. 80°, particularly in the range between approx. 72° and approx. 76°. For incident p-polarized UV light three-layer systems can be used, in which a layer of low refractive material, in particular magnesium fluoride is arranged between two layers of high refractive material and, in the case of the specified wavelength, of minimally absorbent material, in particular of hafnium oxide or aluminum oxide. For example, this allows a residual reflection of perceptibly less than 1% to be achieved in the case of a wavelength of 248 nm at angles of incidence in the range between approx. 72° and approx. 76°.

1 . A method for protecting an optical component having an optical coating against the formation of salt deposits under the influence of ultraviolet light in a wavelength range between approximately 150 nm and approximately 250 nm, the method comprising depositing aluminum oxide (Al 2 O 3 ) as the outer layer of the optical coating.