A hybrid fabrication approach for near-infrared double-helix metamaterials

3D metallic nanostructures offer unique light-manipulation functionalities for nanophotonics, including isotropic magnetic optical response, dispersion manipulation, and engineering of the complex polarization state of light. Particularly, chiral metamaterials offer remarkable opportunities to manipulate the polarization properties of circularly polarized light, leading to pronounced optical activity and circular dichroism [1-5]. As such gold-helix metamaterials have been introduced as compact and broadband circular polarizers [4,5]. However, the fabrication of 3D-chiral metamaterials optimized for operation in the near-infrared/telecom spectral range, has proven technologically demanding and to date their realization seems to be out of reach.