Observations of symmetry-induced topological mode steering in a reconfigurable elastic plate

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 Observations of symmetry-induced topological mode steering in a reconfigurable elastic plate

Prof. Patrick SEBBAH  Physical Review B.
K. Tang, M. Makwana, R. V. Craster, and P. Sebbah
Published in Physical Review B.

Abstract:
 

We investigate vibrational interface modes on elastic plates, to observe distinctive valley-Hall edge states. We have designed a reconfigurable system using clamped holes to create strong scatterers and interfaces that strongly confine vibration. At the physical scales we use here we can scan the field at points throughout the entire plate and extract the mode shapes. Our experimental observations of topological valley transport for sharp and gentle bends and the topological mode coupling around the gentle bend for flexural waves (see Figure), highlight key differences between sharp and gentle bends and the importance of the relative orientations of inclusion sets on either side of the interface. The direct visualization of the mode patterns through spatial scanning of the wavefield, linked with the underlying principles at the junction cells, sheds light on the transport of energy around bends in partitioned media. This important new observation, also confirmed here by theory and simulation, exposes the coupling required for geometrically distinct modes to move from one interface to another.

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