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Proceedings Paper

Edge and higher order topological states in photonic metasurfaces (Conference Presentation)

Paper Abstract

Topological systems are inherently robust to disorder and continuous perturbations, resulting in dissipation-free edge transport of electrons in quantum solids, or reflectionless guiding of photons and phonons in classical wave systems characterized by topological invariants. These established examples of topological physics, however, do not exhaust all possible topological phases, and recently a new class of topological metamaterials characterized by bulk polarization has been introduced. In addition to edge conduction, these systems have been shown to host higher-order topological states, such as corner states. Here, we introduce topological bulk polarization in two-dimensional Kagome photonic meta-structures, and observe topological transitions as the design parameters are tuned. We demonstrate that our topological meta-structure hosts both 1D edge and Wannier-type second-order corner states with unique properties. The edge states have the angular momentum that reverses for opposite propagation direction, thus supporting directional excitation. We also observe the second order topological states protected by the generalized chiral symmetry of the meta-structure, which are localized at the corners and are pinned to ‘zero energy’. Interestingly, unlike the corner states protected by the conventional chiral symmetry, the generalized chiral symmetry of our three-atom sublattice enables their spectral overlap with the continuum of bulk states without leakage. Our findings open new directions in photonics for controlling propagation and manipulating electromagnetic waves, including within the radiative continuum.

Paper Details

Date Published: 9 September 2019
Proc. SPIE 11081, Active Photonic Platforms XI, 110810B (9 September 2019); doi: 10.1117/12.2529305
Show Author Affiliations
Alexander B. Khanikaev, The City College of New York (United States)

Published in SPIE Proceedings Vol. 11081:
Active Photonic Platforms XI
Ganapathi S. Subramania; Stavroula Foteinopoulou, Editor(s)

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