All-graphene perfect broadband THz absorber
Marian Baah, Alesia Paddubskaya, Andrey Novitsky, Nadzeya Valynets, Mukesh Kumar, Tommi Itkonen, Markku Pekkarinen, Ekaterina Soboleva, E. Lähderanta, Maria Kafesaki, Yuri Svirko, P. Kuzhir
Abstract
By combining the 3D printing, electroplating and chemical vapor deposition processes we fabricated “bubble wrap” polymer nanomembrane covered with multilayered graphene. Such a metasurface composed of array of graphene hemispheres shows extremely broadband and almost perfect absorption in terahertz (THz)2 frequency range being robust against macroscopic structural defects including holes and volcanic-like hats on hemispherical metaatoms. The developed theory perfectly explains our experimental findings including virtual independence of the metasurface transmittivity, reflectivity and absorptivity on the angle of incidence in terms of the plasmon dark mode formation. Our approach enables the THz perfect absorber that covers a frequency range spanning from few hundreds of GHz to 1.2 THz, and even more, while the proposed fabrication technique can also be employed in numerous applications that require free standing corrugated graphene/polymer nanomembranes.