Terahertz diffraction enhanced transparency probed in the near field

TitleTerahertz diffraction enhanced transparency probed in the near field
Publication TypeJournal Article
Year of Publication2017
AuthorsA. Halpin, N. van Hoof, A. Bhattacharya, C. Mennes, J Gomez Rivas
JournalPhysical Review B
Volume96
Issue8
Pagination085110
Abstract

Electromagnetically induced transparency in metamaterials allows to engineer structures which transmit narrow spectral ranges of radiation while exhibiting a large group index. Implementation of this phenomenon frequently calls for strong near-field coupling of bright (dipolar) resonances to dark (multipolar) resonances in the metamolecules comprising the metamaterials. The sharpness and contrast of the resulting transparency windows thus depends strongly on how closely these metamolecules can be placed to one another, placing constraints on fabrication capabilities. In this manuscript, we demonstrate that the reliance on near-field interaction strength can be relaxed, and the magnitude of the electromagnetic-induced transparency enhanced, by exploiting the long-range coupling between metamolecules in periodic lattices. By placing dolmen structures resonant at THz frequencies in a periodic lattice, we show a significant increase of the transparency window when the in-plane diffraction is tuned to the resonant frequency of the metamolecules, as confirmed by direct mapping of the THz near-field amplitude across a lattice of dolmens. Through the direct interrogation of the dark resonance in the near field, we show the interplay of near-and far-field couplings in optimizing the response of planar dolmen arrays via diffraction-enhanced transparency.

DOI10.1103/PhysRevB.96.085110
Division

MaSF

Department

PFE

PID2f262fbd99d3c8c3f72d4f5b0eda25bf
Alternate TitlePhys. Rev. B
LabelOA
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