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Mode Evolution in Strongly Coupled Plasmonic Dolmens Fabricated by Templated Assembly

2017

Article

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Plasmonic antennas have enabled a wealth of applications that exploit tailored near-fields and radiative properties, further endowed by the bespoke interactions of multiple resonant building blocks. Specifically, when the interparticle distances are reduced to a few nanometers, coupling may be greatly enhanced leading to ultimate near-field intensities and confinement along with a large energy splitting of resonant modes. While this concept is well-known, the fabrication and characterization of suitable multimers with controlled geometries and few-nanometer gaps remains highly challenging. In this article, we present the topographically templated assembly of single-crystal colloidal gold nanorods into trimers, with a dolmen geometry. This fabrication method enables the precise positioning of high-quality nanorods, with gaps as small as 1.5 nm, which permits a gradual and controlled symmetry breaking by tuning the arrangement of these strongly coupled nanostructures. To characterize the fabricated structures, we perform electron energy loss spectroscopy (EELS) near-field hyperspectral imaging and geometrically accurate EELS, plane wave, and eigenmode full-wave computations to reveal the principles governing the electromagnetic response of such nanostructures that have been extensively studied under plane wave excitation for their Fano resonant properties. These experiments track the evolution of the multipolar interactions with high accuracy as the antenna geometry varies. Our results provide new insights in strongly coupled single-crystal building blocks and open news opportunities for the design and fabrication of plasmonic systems.

Author(s): Flauraud, Valentin and Bernasconi, Gabriel D. and Butet, Jeremy and Mastrangeli, Massimo and Alexander, Duncan T. L. and Martin, Olivier J. F. and Brugger, Jürgen
Journal: ACS Photonics
Volume: 4
Number (issue): 7
Pages: 1661-1668
Year: 2017

Department(s): Physical Intelligence
Bibtex Type: Article (article)

DOI: 10.1021/acsphotonics.6b01026
Eprint: https://doi.org/10.1021/acsphotonics.6b01026
URL: https://doi.org/10.1021/acsphotonics.6b01026

BibTex

@article{doi:10.1021/acsphotonics.6b01026,
  title = {Mode Evolution in Strongly Coupled Plasmonic Dolmens Fabricated by Templated Assembly},
  author = {Flauraud, Valentin and Bernasconi, Gabriel D. and Butet, Jeremy and Mastrangeli, Massimo and Alexander, Duncan T. L. and Martin, Olivier J. F. and Brugger, J{\"u}rgen},
  journal = {ACS Photonics},
  volume = {4},
  number = {7},
  pages = {1661-1668},
  year = {2017},
  eprint = {  https://doi.org/10.1021/acsphotonics.6b01026 },
  url = {  https://doi.org/10.1021/acsphotonics.6b01026 }
}