Frequency-selective surface acoustic invisibility for three-dimensional immersed objects

Mohamed Farhat (1, 2) , Pai-Yen Chen (2) , Sébastien Guenneau (3, 4) , Stefan Enoch (5, 6) , Andrea Alu (2)

1 Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany]
2 ECE - Department of Electrical and Computer Engineering - University of Texas
3 EPSILON - EPSILON
4 CONCEPT - CONCEPT
5 CLARTE - CLARTE
6 FRESNEL - Institut FRESNEL

This paper is focused on the study of acoustic metasurface cloaking, based on the use of appropriate ultrathin pseudosurfaces that may act as cloaking devices for a finite range of frequencies. The technique consists in tailoring the appropriate acoustic surface impedance which cancels the scattered field of a diffracting spherical obstacle placed in the trajectory of an impinging acoustical wave. Our numerical simulations of both near and far fields show a significant reduction of scattering cross section for a moderately broad range of frequencies, confirming the effectiveness of surface cloaks (easier to manufacture and less cumbersome than their bulk counterpart). We also go one step further by proposing a realistic structure obtained by quasiperiodically patterning the surface of a spherical layer. The effective properties of the metasurface are obtained in the framework of homogenization theory and confirm this realistic route to surface cloaking for acoustic waves.

Domaines: Optique [physics.optics]

Mohamed Farhat, Pai-Yen Chen, Sébastien Guenneau, Stefan Enoch, Andrea Alu. Frequency-selective surface acoustic invisibility for three-dimensional immersed objects. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2012, 86, pp.174303. ⟨10.1103/PhysRevB.86.174303⟩. ⟨hal-00759739⟩