showing 11 related works from this author
Surface-Wave Coupling to Single Phononic Subwavelength Resonators
2017
International audience; We propose to achieve manipulation of mechanical vibrations at the micron scale by exploiting the interaction of individual, isolated mechanical resonators with surface acoustic waves. We experimentally investigate a sample consisting of cylindrical pillars individually grown by focused-ion-beam-induced deposition on a piezoelectric substrate, exhibiting different geometrical parameters and excited by a long-wavelength surface elastic wave. The mechanical displacement is strongly confined in the resonators, as shown by field maps obtained by laser scanning interferometry. A tenfold displacement field enhancement compared to the vibration at the surface is obtained, r…
Guidance of surface elastic waves along a linear chain of pillars
2016
International audience; The propagation of surface elastic waves, or surface phonons, is considered along a linear and periodic chain of cylindrical pillars sitting on a semi-infinite solid substrate. A variety of guided modes, some of them exhibiting a very low group velocity, are shown to exist at frequencies close to the resonance frequencies of the pillars. Although the pillar diameter is typically smaller than half the relevant wavelength, lateral radiation on the surface is found to be canceled. Surface guidance is explained by the hybridization of the resonating pillars with the continuum of elastic waves of the substrate.
Extensive tailorability of sound absorption using acoustic metamaterials
2017
We present an experimental demonstration of sound absorption tailorability, using acoustic metamaterials made of resonant cavities that does not rely on any dissipative material. As confirmed by numerical calculation, we particularly show that using quarter-wave-like resonators made of deep subwavelength slits allows a high confinement of the acoustic energy of an incident wave. This leads to enhance the dissipation in the cavities and, consequently, generates strong sound absorption, even over a wide frequency band. We finally demonstrate experimentally the key role of the filling ratio in tailoring such an absorption, using a metamaterial constituted of space-coiled cavities embedded in a…
Subwavelength sound screening by coupling space-coiled Fabry-Perot resonators
2017
We explore broadband and omnidirectional low frequency sound screening based on locally resonant acoustic metamaterials. We show that the coupling of different resonant modes supported by Fabry-Perot cavities can efficiently generate asymmetric lineshapes in the transmission spectrum, leading to a broadband sound opacity. The Fabry-Perot cavities are space-coiled in order to shift the resonant modes under the diffraction edge, which guaranty the opacity band for all incident angles. Indeed, the deep subwavelength feature of the cavities leads to avoid diffraction that have been proved to be the main limitation of omnidirectional capabilities of locally resonant perforated plates. We experim…
Complete band gap in a pillar-based piezoelectric phononic crystal slab
2016
In this paper we have shown that it is possible to obtain the complete phononic band gaps in a square lattice of pillar-based phononic crystal. Bigger phononic band gap width can be obtained by increasing the height of pillar and it filling fraction, f. It is shown that the gap-to-mid-gap ratio of pillar at h/a = 0.5 has increased by 21.2% when it height increased to 1.25 and the gap-to-mid-gap ratio has increased by 12% when the filling fraction is increased from r/a = 0.3 to 0.45. The study also shows bigger band gap width and higher central frequency can be obtained by increasing the filling fraction of pillar.
3034461.pdf
2017
Supplemental document
Guiding and confinement of interface acoustic waves in solid-fluid pillar-based phononic crystals
2016
International audience; Pillar-based phononic crystals exhibit some unique wave phenomena due to the interaction between surface acoustic modes of the substrate and local resonances supported by pillars. In this paper, we extend the investigations by taking into account the presence of a liquid medium. We particularly demonstrate that local resonances dramatically decrease the phase velocity of Scholte-Stoneley wave, which leads to a slow wave at the solid/fluid interface. Moreover, we show that increasing the height of pillars introduces a new set of branches of interface modes and drastically affects the acoustic energy localization. Indeed, while some modes display a highly confined pres…
Solid-fluid interaction in a pillar-based phononic crystal
2016
In this paper, we investigate the wave dispersion of two dimensional pillar-based phononic crystal surrounded in liquid medium. An unit cell structure with reduced pillar height (hp/a)=0.5 and reduced radius (rp/a)=0.3 is simulated using Finite Element Method. The geometrical parameter is chosen to demonstrate a local resonance mechanism that allow the confinement of elastic energy at the interface between the solid and the fluid. In order to identify the energy distribution, we represent the eigenmode at high symmetry (point X) in the first Brillouin zone. The decreasing trend of frequency is also boosted with the increase of pillar height. From the total displacement, the energy is mostly…
3034461.pdf
2017
Supplemental document
Extraordinary nonlinear transmission modulation in a doubly resonant acousto-optical structure
2017
International audience; Acousto-optical modulators usually rely on coherent diffraction of light by a moving acoustic wave, leading to bulky devices with a long interaction length. We propose a subwavelength acousto-optical structure that instead relies on a double resonance to achieve strong modulation at near-infrared wavelengths. A periodic array of metal ridges on a piezoelectric substrate defines cavities that create a resonant dip in the optical transmission spectrum. The ridges simultaneously support large flexural vibrations when resonantly excited by a radio-frequency signal, effectively deforming the cavities and leading to strongly nonlinear acousto-optical modulation. The nano-o…
Density-near-zero using the acoustically induced transparency of a Fano acoustic resonator
2016
International audience; We report experimental results of near-zero mass density involving an acoustic metamaterial supporting Fano resonance. For this, we designed and fabricated an acoustic resonator with two closely coupled modes and measured its transmission properties. Our study reveals that the phenomenon of acoustically induced transparency is accompanied by an effect of near-zero density. Indeed, the dynamic effective parameters obtained from experimental data show the presence of a frequency band where the effective mass density is close to zero, with high transmission levels reaching 0.7. Furthermore, we demonstrate that such effective parameters lead to wave guiding in a 90-degre…