Topological Dislocations for Plasmonic Mode Localization in Arrays of Nanoscale Rectangular Au Apertures: Implications for Optical Communications

Abstract

We study the localization of plasmonic modes on topological dislocations obtained by an abrupt change in the geometry of unit cells in a plasmonic metasurface comprised of a nanoscale array of rectangular apertures. We experimentally demonstrate mode localization in line defects and point singularities in the topology. These results are confirmed by numerical simulations of the near field distributions along the topology boundaries. We present structures with line dislocations supporting dark and bright modes. Moreover, we show that in structures with point dislocations the localization strength can be further manipulated by modifying the topological order of the structure.

Advances and Prospects in Topological Nanoparticle Photonics

“…They may have fundamental size limits, or the time-reversal breaking mechanisms required to observe edge states may simply be too weak at THz or higher frequencies. 1D topological phases without spinful time-reversal (TR) symmetry such as the Kitaev chain and SSH model are natural models to study, and they find natural implementation in systems of nanoparticles, both dielectric and metallic. ,,,− Higher-order systems such as 2D arrays of nanoparticles and plasmonic metasurfaces ,, allow us to study edge modes, such as in the expanded/contracted honeycomb lattice and the valley states which emerge on a square lattice . An experimental study of the edge states in the honeycomb system allowed for the differentiation of contributions from higher-order Bloch harmonics and demonstrated the robustness of the edge states at telecom frequencies.…”

“…The study of edge states in topological photonic systems can give us crucial insights on the topological properties of these systems. However, plasmonic systems suffer large losses during nanoscale propagation, so a key focus in topological nanophotonics will be particle-like (or localized) states ,− such as corner states, which have tight confinement in all directions. ,,,− …”

“…In Section 4, we give a short review of the current state of nonlinear topological nanophotonics, and in Section 5, we extend our discussion of topological nanophotonics to the 35 and plasmonic metasurfaces. 36 Semiconductor nanocavity arrays, 37 2D materials and hybrid systems including photonic structures, 38 and topological insulator nanoparticles. 23 system of topological insulator nanoparticles (in contrast to the metallic and dielectric nanoparticles previously discussed).…”

“…Systems with nanoscale dimensions operating from visible to THz frequencies: Dielectric nanoparticles (adapted with permission from ref , Copyright 2015 American Physical Society), plasmonic nanoparticles, dielectric nanostructures, figure adapted with permission from ref , copyright 2019 Nature Publishing Group. 2D arrays of nanoparticles and plasmonic metasurfaces . Semiconductor nanocavity arrays, 2D materials and hybrid systems including photonic structures, and topological insulator nanoparticles .…”

“…Semiconductor nanocavity arrays, 2D materials and hybrid systems including photonic structures, and topological insulator nanoparticles . Figures from refs ,,,,− licensed under CC BY 4.0, . Figure from ref licensed under CC BY 3.0, .…”