Metasurfaces atop metamaterials: surface morphology induces linear dichroism in gyroid optical metamaterials

Research output: Contribution to journalArticle

Authors

  • James Dolan
  • Raphael Dehmel
  • Yibei Gu
  • Ulrich Wiesner
  • Timothy Wilkinson
  • Ilja Gunkel
  • Ortwin Hess
  • Jeremy J. Baumberg
  • Ullrich Steiner
  • Matthias Saba
  • Bodo Wilts

Colleges, School and Institutes

External organisations

  • University of Cambridge
  • Department of Materials Science and Engineering, Cornell University
  • Adolphe Merkle Institute, Ch. des Verdiers 4, 1700 Fribourg
  • Imperial College London
  • Adolphe Merkle Institute
  • Cavendish Laboratory, Department of Physics
  • Nanophotonics Centre
  • Cavendish Laboratory

Abstract

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.

Bibliographic note

J. A. Dolan, R. Dehmel, A. Demetriadou, Y. Gu, U. Wiesner, T. D. Wilkinson, I. Gunkel, O. Hess, J. J. Baumberg, U. Steiner, M. Saba, B. D. Wilts, Adv. Mater. 2019, 31, 1803478. https://doi.org/10.1002/adma.201803478

Details

Original languageEnglish
Article number1803478
Number of pages8
JournalAdvanced Materials
Volume31
Issue number2
Early online date4 Nov 2018
Publication statusPublished - 11 Jan 2019

Keywords

  • cubic symmetry, gyroid-structured materials, metasurfaces, optical metamaterials, optical anisotropy