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Effect of local periodic perturbations on the topological edge mode of the SSH-model (Conference Presentation)
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Paper Abstract

Topological edge states draw their unique robustness against perturbations from a topological invariant of the bulk of the system. As long as the topological properties persist, the edge transport is not perturbed by static defects, which is referred to as the bulk-edge correspondence. In our work we demonstrate that local periodic perturbations of the interface can destroy the topological protection even if the bulk of the system stays unperturbed. As model system we consider the Su-Schrieffer-Heeger (SSH) model realized in coupled plasmonic waveguide arrays with alternating short and long separations. Interfacing two SSH chains with different dimerizations we induce the topological edge mode. The temporal perturbations are realized by periodically bending the waveguide at the interface. The spatial evolution of surface plasmon polaritons (SPPs) in the array is monitored by real- and Fourier space leakage radiation microscopy. In Fourier space we observe that time-periodic perturbations of the interface create Floquet replicas of the topological edge mode. If the driving frequency is in the range for which the first Floquet replicas cross the static bands, the topological edge state couples to bulk states and the topological protection is destroyed resulting in delocalization of SPPs in real space. Otherwise the topological protection is conserved and SPPs stay localized at the interface. Our experimental findings are in full agreement with the theoretical analysis based on Floquet theory and illuminates the generalization of the bulk-edge correspondence for Floquet systems for the special case of a static bulk.

Paper Details

Date Published: 4 March 2019
Proc. SPIE 10933, Advances in Photonics of Quantum Computing, Memory, and Communication XII, 109330T (4 March 2019); doi: 10.1117/12.2507865
Show Author Affiliations
Zlata Cherpakova, Rheinische Friedrich-Wilhelms-Univ. Bonn (Germany)
Stefan Linden, Rheinische Friedrich-Wilhelms-Univ. Bonn (Germany)

Published in SPIE Proceedings Vol. 10933:
Advances in Photonics of Quantum Computing, Memory, and Communication XII
Philip R. Hemmer; Alan L. Migdall; Zameer Ul Hasan, Editor(s)

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