Metal oxide metasurfaces for active control and space technology

Recently metal oxides have been introduced as promising materials for infrared and active plasmonics. By designing nanoantennas and metamaterials using transparent conducting oxides (TCOs), we can achieve strong light-matter interactions in the infrared while maintaining high transparency in the visible range. These properties have been used to design new types of infrared active surfaces for optical sensing and metamaterials [1, 2]. Compared to noble-metals, the TCOs offer a strongly reduced negative permittivity which allows for much more compact resonant nanostructures and hence a higher density of elements per square wavelength. Up to 80 resonant elements per square wavelength were realized using ITO split-ring resonators.