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2005
Conference Paper
Titel
Precision optical and antireflection multilayer and gradient coatings containing reactively sputtered oxides, nitrides and fluorides
Abstract
Optical coatings have been deposited by pulse magnetron sputtering of the target materials silicon and aluminium using the reactive gases oxygen, nitrogen and fluorine. The measured refractive index and roughness of the SiO2, Si3N4, Ta2O5 and Al2O3 films indicate the deposition of very dense and smooth films. Absorption of SiO2 and Al2O3 films is low even at a wavelength of 193nm. The sputter deposited AlF3 layers have low absorption until 150 nm but then show an absorption edge. Examples of multilayer include antireflective coatings for ophthalmic lenses and cut filters consisting of up to 150 ?/4 layers. These films were produced at a single stationary coating station without interruption of film deposition by changing the reactive gas during the plasma process. This process was also used for the deposition of rugate filters with apodisation function by continuous variation of the reactive gas composition during the deposition.