Scaling the Artificial Polariton Bandgap at Infrared Frequencies Using Indium Tin Oxide Nanorod Arrays

Xiangfan Chen, Peijun Guo, Cheng He, Biqin Dong, Leonidas E. Ocola, Richard D Schaller, Robert P. H. Chang, Cheng Sun

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Artificial polariton bandgaps at infrared frequencies are investigated by exploiting the strong coupling of electromagnetic waves with induced electric dipoles in two-dimensional (2D) indium tin oxide nanorod arrays (ITO-NRAs). The electric dipoles originate from the collective oscillations of free electrons within the individual ITO nanorods undergoing plasmonic resonance. Controlling the near-field interactions among the neighboring electric dipoles allows for manipulation of the collective polariton modes that are manifested as a polariton bandgap. A theoretical model is developed to understand the coupled phenomena underlying the unique characteristics of plasmon-polariton bandgaps. With high-degree geometric control of the ITO-NRAs, it is experimentally demonstrated that reducing the spacing between ITO nanorods in a square array strengthens the near-field interactions and thus results in a redshift as well as broadening of the polariton bandgap. Furthermore, arranging ITO-NRAs in a rectangular lattice breaks the symmetry with respect to the principle axis, which leads to a splitting of the collective polariton modes owing to the competition between the quasi-longitudinally and quasi-transversely coupled plasmon-polariton modes. The work highlights the use of a classical dipole coupling method for scaling polariton bandgaps to the infrared in artificial plasmonic lattices, thereby offering a new design dimension for infrared sensing, absorbers, and optical communications.

Original languageEnglish
JournalAdvanced Optical Materials
DOIs
Publication statusAccepted/In press - 2016

Keywords

  • Electric dipole coupling
  • Indium tin oxide nanorod arrays
  • Infrared
  • Plasmon-polariton bandgaps

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics

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