LMA - Laboratoire de Mécanique et d’Acoustique

R. Fleury - Active acoustic metamaterials : breaking reciprocity, Hermiticity, or both at the same time

Amphithéâtre François Canac, LMA

Le 17 octobre 2017 de 11h00 à 12h00

Romain Fleury
Prof. EPFL

In this seminar, I will discuss our recent theoretical and experimental work about linear active metamaterials, i.e. artificial acoustic media that require an external source of power. In a first part of the talk, I will discuss artificial media that can break reciprocity of wave propagation. These are active, but yet do not exchange power with the acoustic wave. Differently, the second part of the talk will focus on a different type of active metamaterial, which can provide gain or loss to the acoustic wave, without breaking time-reversal symmetry. These media are non-Hermitian and reciprocal, and can support interesting power-compensation and transparency effects. Finally, in a third part we will show that it is also possible to break reciprocity and Hermiticity at the same time by breaking time-invariance in a specific way, leading to a novel class of non-reciprocal non-Hermitian systems capable of one-way parametric amplification. Altogether, our work highlights the relevance of active systems for full control of the power flow at the microscopic scale.

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