Fabrication of large-area 3D optical fishnet metamaterial by laser interference lithography

Centimeter-scale 3D fishnet metamaterial with negative refractive index in the near infrared spectral range is demonstrated. The large-area fabrication is realized using a conventional laser interference lithography technique in combination with a tri-layer lift-off procedure. This method allows us to effectively achieve a centimeter-scale 3D fishnet structure with a pitch of 600 nm and five functional Ag/SiO2 bi-layers with a total thickness of 300 nm. The experimental transmission spectrum correlates well with simulation results. Effective refractive index versus frequency associated with permittivity and permeability are retrieved. Two negative refractive index regions are found in the near-infrared spectral range.