Observation of topological valley modes in an elastic hexagonal lattice
By J. Vilà, R. Pal, Massimo Ruzzene. 2017
224 citations recorded by the source corpus.
We report on the experimental observation of topologically protected edge waves in a two-dimensional elastic hexagonal lattice. The lattice is designed to feature K point Dirac cones that are well separated from the other numerous elastic wave modes characterizing this continuous structure. We exploit the arrangement of localized masses at the nodes to break mirror symmetry at the unit cell level, which opens a frequency bandgap. This produces a non-trivial band structure that supports topologically protected edge states along the interface between two realizations of the lattice obtained through mirror symmetry. Detailed numerical models support the investigations of the occurrence of the edge states, while their existence is verified through full-field experimental measurements. The test results show the confinement of the topologically protected edge states along pre-defined interfaces and illustrate the lack of significant backscattering at sharp corners. Experiments conducted on a trivial waveguide in an otherwise uniformly periodic lattice reveal the inability of a perturbation to propagate and its sensitivity to backscattering, which suggests the superior waveguiding performance of the class of non-trivial interfaces investigated herein.
Subfields: Atomic and Molecular Physics, and Optics, Statistical and Nonlinear Physics
View Paper: https://www.semanticscholar.org/paper/e91d291867845333b47bd89d31cafd4eb202c4a0
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In Atomic and Molecular Physics, and Optics
Citations in the corpus
- Experimental Observation of Topologically Protected Helical Edge Modes in Patterned Elastic Plates (2018, background): “This is conveniently achieved by breaking spatial inversion symmetry at the unit cell level, which is an approach that has been successfully applied for flexural waves in plates [25,26] as well as in mechanical lattices with resonators [27].”