Submicron periodic structures in metal oxide coating via laser ablation and thermal oxidation

Abstract

Nano- and micro-structuring of transparent glass for IR or visible spectrum applications is challenging due to low yield and slow processes, especially while maintaining high surface quality. The method proposed in this work involves the structuring and subsequent thermal oxidation of a thin metallic layer on a glass substrate. Annealing of the structured metal layer produces a transparent fully inorganic oxide surface with periodic patterns, avoiding the subtleties of glass structuring. A new method for the formation of sub-micrometer non-absorbing gratings with 750 nm periodicity is presented by direct laser interference patterning (DLIP) of thin tantalum layers on fused silica substrates followed by thermal oxidation by annealing. This method aims to improve the field of laser optics by providing a scalable and efficient method for the creation of precise metal-oxide photonic structures.