Antireflection coating for ultraviolet light at large angles of incidence

• Main Authors: KUSCHNEREIT RALF, PAUL HANS-JOCHEN
• Format: Patent
• Language: English
• Published: 24.02.2004
• Edition: 7
• Subjects: APPARATUS SPECIALLY ADAPTED THEREFOR; BASIC ELECTRIC ELEMENTS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; CINEMATOGRAPHY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DEVICES USING STIMULATED EMISSION; DIFFUSION TREATMENT OF METALLIC MATERIAL; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; ELECTROGRAPHY; HOLOGRAPHY; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; MATERIALS THEREFOR; METALLURGY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; ORIGINALS THEREFOR; PHOTOGRAPHY; PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES,e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTORDEVICES; PHYSICS; SEMICONDUCTOR DEVICES; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

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°.