Floquet topological insulators for sound.
The unique conduction properties of condensed matter systems with topological order have recently inspired a quest for the similar effects in classical wave phenomena. Acoustic topological insulators, in particular, hold the promise to revolutionize our ability to control sound, allowing for large isolation in the bulk and broadband one-way transport along their edges, with topological immunity against structural defects and disorder. So far, these fascinating properties have been obtained relying on moving media, which may introduce noise and absorption losses, hindering the practical potential of topological acoustics. Here we overcome these limitations by modulating in time the acoustic properties of a lattice of resonators, introducing the concept of acoustic Floquet topological insulators. We show that acoustic waves provide a fertile ground to apply the anomalous physics of Floquet topological insulators, and demonstrate their relevance for a wide range of acoustic applications, including broadband acoustic isolation and topologically protected, nonreciprocal acoustic emitters.
Department of Electrical and Computer Engineering, The University of Texas at Austin, 1616 Guadalupe Street UTA 7.215, Austin, Texas 78701, USA.|ESPCI Paris Tech and Langevin Institute, 1 rue Jussieu, 75005 Paris, France.|Institute of Electrical Engineering, EPFL, Route Cantonale, 1015 Lausanne, Switzerland.
Romain
0000-0002-9486-6854
R
Fleury
Department of Physics, Queens College of The City University of New York, Queens, New York 11367, USA.|Department of Physics, The Graduate Center of The City University of New York, New York, New York 10016, USA.
Alexander B
AB
Khanikaev
Department of Electrical and Computer Engineering, The University of Texas at Austin, 1616 Guadalupe Street UTA 7.215, Austin, Texas 78701, USA.
Andrea
A
Alù