Metasurfaces Atop Metamaterials: Surface Morphology Induces Linear Dichroism in Gyroid Optical Metamaterials.
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Dolan, J. A., Dehmel, R., Demetriadou, A., Gu, Y., Wiesner, U., Wilkinson, T. D., Gunkel, I., et al. (2019). Metasurfaces Atop Metamaterials: Surface Morphology Induces Linear Dichroism in Gyroid Optical Metamaterials.. Adv Mater, 31 (2), e1803478. https://doi.org/10.1002/adma.201803478
Optical metamaterials offer the tantalizing possibility of creating extraordinary optical properties through the careful design and arrangement of subwavelength structural units. Gyroid-structured optical metamaterials possess a chiral, cubic, and triply periodic bulk morphology that exhibits a redshifted effective plasma frequency. They also exhibit a strong linear dichroism, the origin of which is not yet understood. Here, the interaction of light with gold gyroid optical metamaterials is studied and a strong correlation between the surface morphology and its linear dichroism is found. The termination of the gyroid surface breaks the cubic symmetry of the bulk lattice and gives rise to the observed wavelength- and polarization-dependent reflection. The results show that light couples into both localized and propagating plasmon modes associated with anisotropic surface protrusions and the gaps between such protrusions. The localized surface modes give rise to the anisotropic optical response, creating the linear dichroism. Simulated reflection spectra are highly sensitive to minute details of these surface terminations, down to the nanometer level, and can be understood with analogy to the optical properties of a 2D anisotropic metasurface atop a 3D isotropic metamaterial. This pronounced sensitivity to the subwavelength surface morphology has significant consequences for both the design and application of optical metamaterials.
This research was supported through the Swiss National Science Foundation through grant 163220 (U.S.) and the Ambizione program grant 168223 (B.D.W.), the National Center of Competence in Research Bio-Inspired Materials (I.G., U.S., B.D.W), the Adolphe Merkle Foundation (I.G., U.S., B.D.W), the Engineering and Physical Sciences Research Council (EPSRC) through the Cambridge NanoDTC EP/G037221/1, EP/G060649/1 (R.D., J.A.D., J.J.B.), and EP/L027151/1 (A.D, O.H., M.S.), and ERC LINASS 320503 (J.J.B.). This project has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 706329/cOMPoSe (I.G.). Y.G. and U.W. thank the National Science Foundation (DMR-1707836) for financial support.
Engineering and Physical Sciences Research Council (EP/L027151/1)
Engineering and Physical Sciences Research Council (EP/N016920/1)
Engineering and Physical Sciences Research Council (EP/M016218/1)
Engineering and Physical Sciences Research Council (EP/G060649/1)
European Research Council (320503)
Engineering and Physical Sciences Research Council (EP/G037221/1)
Engineering and Physical Sciences Research Council (EP/L015978/1)
External DOI: https://doi.org/10.1002/adma.201803478
This record's URL: https://www.repository.cam.ac.uk/handle/1810/286389
Attribution 4.0 International
Licence URL: https://creativecommons.org/licenses/by/4.0/