Higher-order topology in plasmonic kagome lattices

Abstract

We study the topological properties of a kagome plasmonic metasurface, modelled with a coupled dipole method which naturally includes retarded long range interactions. We demonstrate the system supports an obstructed atomic limit phase through the calculation of Wilson loops. Then we characterise the hierarchy of topological boundary modes hosted by the subwavelength array of plasmonic nanoparticles: both one-dimensional edge modes as well as zero-dimensional corner modes. We determine the properties of these modes which robustly confine light at subwavelength scales, calculate the local density of photonic states at edge and corner modes frequencies, and demonstrate the selective excitation of delocalised corner modes in a topological cavity, through non-zero orbital angular momentum beam excitation.

main: 7 pages, 5 figures. supp: 9 pages, 7 figures

References in corpus (6)

• Higher-order topological insulators and semimetals on the breathing Kagome and pyrochlore lattices
• Optical Momentum, Spin, and Angular Momentum in Dispersive Media
• Photonic Band Structure of Two-dimensional Atomic Lattices
• The Nature of Topological Protection in Spin and Valley Hall Insulators
• Exciting Pseudospin Dependent Edge States in Plasmonic Metasurfaces
• Near- and Far-Field Excitation of Topological Plasmonic Metasurfaces

Cited by in corpus (4)

• A brief review of topological photonics in one, two, and three dimensions
• $2^n$-root weak, Chern, and higher-order topological insulators, and $2^n$-root topological semimetals
• Corner modes of the breathing kagome lattice: origin and robustness
• Topological Photonics on a Small Scale