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O: Fachverband Oberflächenphysik

O 91: Plasmonics and Nanooptics V: Waveguides and Antennas

O 91.5: Vortrag

Freitag, 31. März 2023, 11:30–11:45, CHE 89

Spatio-spectral metrics in electron energy loss spectroscopy as a tool to resolve nearly degenerate plasmon modes — Michal Horák, Andrea Konečná, Tomáš Šikola, and •Vlastimil Křápek — Brno University of Technology, Czechia

Electron energy loss spectroscopy (EELS) is utilized to characterize localized surface plasmon modes supported by plasmonic antennas (PAs) with excellent spatial resolution, including studies of hybridized modes in dimer PAs [1,2,3]. However, the spectral resolution of EELS is often insufficient to resolve the hybridized modes for weakly coupled dimers.

Here we address this issue for a case study of the dimer PA composed of two gold discs. We analyze four nearly degenerate hybridized dipole modes. With a traditional approach, the modes cannot be experimentally identified with EELS. Therefore, we propose several metrics that employ the spatial and spectral sensitivity of EELS simultaneously. We apply the metrics to experimental EELS data, demonstrating their ability to resolve three of the above-mentioned modes (with transverse bonding and antibonding modes still unresolved), identify them unequivocally, and determine their energies. In this respect, the spatio-spectral metrics increase the information extracted from EELS applied to PAs.

[1] V. Křápek et al., Nanophotonics 9, 623 (2020).

[2] O. Bitton et al., Nat. Commun. 11, 487 (2020).

[3] J.-H. Song et al., Nat. Commun. 12, 48 (2021).