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Acoustic metamaterials I

17:10 Invited talk : Experimental Demonstration of a Soft 3D Acoustic Metamaterial with Negative Index

Thomas Brunet, Kevin Zimny, Artem Kovalenko, Benoit Mascaro, Jacques Leng, Christophe Aristegui, Olivier Poncelet, Olivier Mondain-Monval

University of Bordeaux (France)

We report a new class of locally resonant ultrasonic metafluids consisting of a concentrated suspension of macroporous microbeads engineered using soft matter techniques.
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17:30 : Enhanced picosecond acoustic response near the surface plasmon resonance of Ni/Au-nanoparticles metastructures

Oleksandr Kovalenko, Yu Liu, Ji-Wan Kim, Gilles Versini, Jean-Yves Bigot

Strasbourg University (France)

In this work we consider the interaction between picosecond acoustic pulses generated in a 300nm thick Ni film and the localized Surface Plasmons of Au nanoparticles. The monolayer of gold nanoparticles, self-organized on top of the Ni film, allows us detecting the acoustic signal as a function of wavelength near their surface plasmon resonance. Near resonance, an amplification factor of 55 is measured as compared to the bare Ni film. Our approach precludes useful applications in opto-acoustics and magneto-acoustics.
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17:45 : Time Reversal in bubbly metamaterials

Maxime Lanoy (1),Valentin Leroy (1),Arnaud Tourin (2)

(1)ESPCI ParisTech (France) , (2)Paris Diderot University (France)

We present a way to combine the isotropic resonance of gas bubbles in water and the coherent multiple scattering of a disordered sample or bubbles in order to focus acoustic energy beyond the diffraction limit using time reversal mirrors. In the realistic case where we consider thermal and viscous losses we show that the low frequency modes have to be involved.
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