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Vincent Laude - One of the best experts on this subject based on the ideXlab platform.
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Channeled spectrum in the transmission of Phononic Crystal waveguides
Journal of Sound and Vibration, 2018Co-Authors: Yanfeng Wang, Yuesheng Wang, Tingting Wang, Jun-wei Liang, Vincent LaudeAbstract:Waveguiding in a Phononic Crystal (PC) can be achieved along either linear line defects or a sequence of cavities, for frequencies belonging to a complete bandgap. When waves are coupled inside a PC waveguide, modulations in the frequency transmission are generally observed, leading to the formation of a channeled spectrum. We show that the channeled spectrum results from the interference of forward and backward guided Bloch waves. We first theoretically develop a Bloch wave interference model. Then, we consider the case of linear waveguides and of coupled-resonator waveguides formed in a 2D square PC composed of water cylinders in mercury. The transmission properties of waveguides with different length and defect distribution are examined. In all cases, the observed channeled spectra are well explained by the theoretical model. This work is relevant to the design of new acoustic and elastic wave devices.
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Reconfigurable Phononic Crystal circuits formed by coupled acoustoelastic resonators
Physical Review Applied, 2017Co-Authors: Yanfeng Wang, Tingting Wang, Yue Wang, Vincent LaudeAbstract:Reconfigurable Phononic circuits can be created by the selective fluid filling of holes in a solid Phononic Crystal. For frequencies within a complete band gap of the bare Phononic Crystal, the filled holes become cavities that sustain acoustoelastic defect modes. Those cavities couple evanescently with a strength that depends on their separation. We investigate the dispersion relation and the transmission properties of coupled-resonator acoustoelastic waveguides formed by a chain of cavities. While the dispersion relation is strongly dependent on the separation between cavities, transmission properties are only weakly dependent on the details of the Phononic circuit for a fixed separation. Furthermore, depending on the polarization of the source of waves, defect modes can be excited selectively. As a result, rather arbitrary Phononic circuits can be created, such as multiply bent waveguides or wave splitters.
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Guidance of surface waves in a micron-scale Phononic Crystal line-defect waveguide
Applied Physics Letters, 2015Co-Authors: Sarah Benchabane, Olivier Gaiffe, Roland Salut, Gwenn Ulliac, Vincent Laude, Kimmo KokkonenAbstract:We report on the direct observation of trapping and guiding of surface-guided elastic waves in a linear defect introduced into a micron-scale Phononic Crystal. Elastic field amplitude detection using laser scanning interferometry was used to characterize the different transmission regimes of the one-period wide line defect in a Phononic Crystal structure as a function of frequency and to discriminate Phononic waveguiding from transmission outside the band gap. Surface density-of-states computations support the experimental observations.
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waveguiding inside the complete band gap of a Phononic Crystal slab
Physical Review E, 2007Co-Authors: Fuli Hsiao, Abdelkrim Khelif, Abdelkrim Choujaa, Hanane Moubchir, Chii Chang Chen, Vincent LaudeAbstract:The propagation of acoustic waves in a square-lattice Phononic Crystal slab consisting of a single layer of spherical steel beads in a solid epoxy matrix is studied experimentally. Waves are excited by an ultrasonic transducer and fully characterized on the slab surface by laser interferometry. A complete band gap is found to extend around 300 kHz, in good agreement with theoretical predictions. The transmission attenuation caused by absorption and band gap effects is obtained as a function of frequency and propagation distance. Well confined acoustic wave propagation inside a line-defect waveguide is further observed experimentally.
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scattering of surface acoustic waves by a Phononic Crystal revealed by heterodyne interferometry
Applied Physics Letters, 2007Co-Authors: Kimmo Kokkonen, Sarah Benchabane, Abdelkrim Khelif, Matti Kaivola, Vincent LaudeAbstract:Surface acoustic wave propagation within a two-dimensional Phononic band gap structure has been studied using a heterodyne laser interferometer. Acoustic waves are launched by interdigital transducers towards a square lattice of holes etched in a piezoelectric medium. Interferometer measurements performed at frequencies lying below, within, and above the expected band gap frequency range provide direct information of the wave interaction with the Phononic Crystal, revealing anisotropic scattering into higher diffraction orders depending on the apparent grating pitch at the boundary between the Phononic Crystal and free surface. Furthermore, the measurements also confirm the existence of an elastic band gap, in accordance with previous electrical measurements and theoretical predictions.
Abdelkrim Khelif - One of the best experts on this subject based on the ideXlab platform.
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Design and experimental validation of a temperature-driven adaptive Phononic Crystal slab
Smart Materials and Structures, 2019Co-Authors: Kévin Billon, Morvan Ouisse, Emeline Sadoulet, Manuel Collet, Pauline Butaud, Gael Chevallier, Abdelkrim KhelifAbstract:In this paper, an adaptive Phononic Crystal slab based on the combination of metallic parts and highly dissipative polymeric interfaces is designed. Cylindrical pillars are composed of shape memory polymer and aluminum deposited periodically on the aluminum slab. The mechanical properties of the polymer depend on both temperature and frequency and can radically change from glassy to rubbery state, with various combinations of high/low stiffness and high/low dissipation. A 3D finite element model of the cell is developed for the design of the metamaterial. The shifted-cell operator technique is used to correctly handle damping effects in the dispersion analysis. In order to validate the design and the adaptive character of the metamaterial, results issued from a full 3D model of a finite structure embedding an interface composed by a distributed set of the unit cells are presented. Various driving temperatures are used to change the behaviour of the system, and numerical results obtained on the adaptive structure are compared to experimental ones. Two states are obtained by changing the temperature of the polymeric interface: at 25°C a bandgap is visible around a selected resonance frequency, and it doesn't exist anymore above the glass transition temperature, where the Phononic Crystal slab tends to behave as an homogeneous plate. Numerical and experimental results show energy propagation along the borders of the slab in the bandgap.
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Ultra-wide acoustic band gaps in pillar-based Phononic Crystal strips
Journal of Applied Physics, 2015Co-Authors: Etienne Coffy, Thomas Lavergne, Mahmoud Addouche, Sébastien Euphrasie, Pascal Vairac, Abdelkrim KhelifAbstract:An original approach for designing a one dimensional Phononic Crystal strip with an ultra-wide band gap is presented. The strip consists of periodic pillars erected on a tailored beam, enabling the generation of a band gap that is due to both Bragg scattering and local resonances. The optimized combination of both effects results in the lowering and the widening of the main band gap, ultimately leading to a gap-to-midgap ratio of 138%. The design method used to improve the band gap width is based on the flattening of Phononic bands and relies on the study of the modal energy distribution within the unit cell. The computed transmission through a finite number of periods corroborates the dispersion diagram. The strong attenuation, in excess of 150 dB for only five periods, highlights the interest of such ultra-wide band gap Phononic Crystal strips.
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acoustic confinement and waveguiding with a line defect structure in Phononic Crystal slabs
Journal of Applied Physics, 2010Co-Authors: Abdelkrim Khelif, Saeed Mohammadi, Ali Adibi, Ali A Eftekhar, Boujamaa AoubizaAbstract:We present a new way of forming Phononic Crystal waveguides by coupling a series of line-defect resonators. The dispersion proprieties of these coupled resonator acoustic waveguides (CRAW) can be engineered by using their geometrical parameters. We show that single-mode guiding over a large bandwidth is possible in CRAW formed in a honeycomb-lattice Phononic Crystal slab of holes in zinc oxide. In addition, a finite length of CRAW structure acts as an efficient selective acoustic filter for Lamb waves.
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waveguiding inside the complete band gap of a Phononic Crystal slab
Physical Review E, 2007Co-Authors: Fuli Hsiao, Abdelkrim Khelif, Abdelkrim Choujaa, Hanane Moubchir, Chii Chang Chen, Vincent LaudeAbstract:The propagation of acoustic waves in a square-lattice Phononic Crystal slab consisting of a single layer of spherical steel beads in a solid epoxy matrix is studied experimentally. Waves are excited by an ultrasonic transducer and fully characterized on the slab surface by laser interferometry. A complete band gap is found to extend around 300 kHz, in good agreement with theoretical predictions. The transmission attenuation caused by absorption and band gap effects is obtained as a function of frequency and propagation distance. Well confined acoustic wave propagation inside a line-defect waveguide is further observed experimentally.
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scattering of surface acoustic waves by a Phononic Crystal revealed by heterodyne interferometry
Applied Physics Letters, 2007Co-Authors: Kimmo Kokkonen, Sarah Benchabane, Abdelkrim Khelif, Matti Kaivola, Vincent LaudeAbstract:Surface acoustic wave propagation within a two-dimensional Phononic band gap structure has been studied using a heterodyne laser interferometer. Acoustic waves are launched by interdigital transducers towards a square lattice of holes etched in a piezoelectric medium. Interferometer measurements performed at frequencies lying below, within, and above the expected band gap frequency range provide direct information of the wave interaction with the Phononic Crystal, revealing anisotropic scattering into higher diffraction orders depending on the apparent grating pitch at the boundary between the Phononic Crystal and free surface. Furthermore, the measurements also confirm the existence of an elastic band gap, in accordance with previous electrical measurements and theoretical predictions.
Sarah Benchabane - One of the best experts on this subject based on the ideXlab platform.
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Guidance of surface waves in a micron-scale Phononic Crystal line-defect waveguide
Applied Physics Letters, 2015Co-Authors: Sarah Benchabane, Olivier Gaiffe, Roland Salut, Gwenn Ulliac, Vincent Laude, Kimmo KokkonenAbstract:We report on the direct observation of trapping and guiding of surface-guided elastic waves in a linear defect introduced into a micron-scale Phononic Crystal. Elastic field amplitude detection using laser scanning interferometry was used to characterize the different transmission regimes of the one-period wide line defect in a Phononic Crystal structure as a function of frequency and to discriminate Phononic waveguiding from transmission outside the band gap. Surface density-of-states computations support the experimental observations.
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scattering of surface acoustic waves by a Phononic Crystal revealed by heterodyne interferometry
Applied Physics Letters, 2007Co-Authors: Kimmo Kokkonen, Sarah Benchabane, Abdelkrim Khelif, Matti Kaivola, Vincent LaudeAbstract:Surface acoustic wave propagation within a two-dimensional Phononic band gap structure has been studied using a heterodyne laser interferometer. Acoustic waves are launched by interdigital transducers towards a square lattice of holes etched in a piezoelectric medium. Interferometer measurements performed at frequencies lying below, within, and above the expected band gap frequency range provide direct information of the wave interaction with the Phononic Crystal, revealing anisotropic scattering into higher diffraction orders depending on the apparent grating pitch at the boundary between the Phononic Crystal and free surface. Furthermore, the measurements also confirm the existence of an elastic band gap, in accordance with previous electrical measurements and theoretical predictions.
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evidence for complete surface wave band gap in a piezoelectric Phononic Crystal
Physical Review E, 2006Co-Authors: Sarah Benchabane, Abdelkrim Khelif, Jeanyves Rauch, Laurent Robert, Vincent LaudeAbstract:A complete surface acoustic wave band gap is found experimentally in a two-dimensional square-lattice piezoelectric Phononic Crystal etched in lithium niobate. Propagation in the Phononic Crystal is studied by direct generation and detection of surface waves using interdigital transducers. The complete band gap extends from 203 to 226 MHZ, in good agreement with theoretical predictions. Near the upper edge of the complete band gap, it is observed that radiation to the bulk of the substrate dominates. This observation is explained by introducing the concept of the sound line.
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evidence for complete surface wave band gap in a piezoelectric Phononic Crystal
Physical Review E, 2006Co-Authors: Sarah Benchabane, Abdelkrim Khelif, Jeanyves Rauch, Laurent Robert, Vincent LaudeAbstract:Phononic Crystals ultimately offer control of the propagation of acoustic or elastic waves on a wavelength scale. Much like photonic Crystals in the case of optical and electromagnetic waves, they consist of two- or three-dimensional periodic arrangements of two materials with differing elastic constants 1,2 that can give rise to absolute acoustic stop bands under well-chosen geometrical conditions. First demonstrations have generally been in the audible and ultrasonic range, with millimetric or larger wavelengths 3–8. For instance, evanescent tunneling through a Phononic Crystal PC was observed 7, and guiding along and trapping of energy inside defects managed in a PC were demonstrated 9,10. These theories and experiments have often been devoted to bulk acoustic waves BAW’s for which the external boundaries enclosing the Phononic Crystal do not play a significant role in wave propagation. Yet, if Phononic Crystals have recently moved to the hypersonic region 11–13 and now appear as interesting candidates for high-frequency signal processing applications, the physical pathways to Phononic devices still need to be defined. The case of surface acoustic waves SAW’s has also attracted sustained attention 14–18. SAW’s are guided along the surface of a solid or liquid material and are hence confined in the direction normal to the surface. As a consequence, the two-dimensional periodic structuring of the surface can be expected to provide at least to a certain extent the same Phononic properties for SAW’s as would a three-dimensional Phononic Crystal for BAW’s. This situation has a strong connection with the case of plasmonic Crystals 19. Phononic devices relying on surface waves in piezoelectric materials are attractive since SAW’s can be directly excited and detected at the surface by use of interdigital transducers IDT’s20. SAW-based components are extensively used as radio-frequency filters in wireless telecommunication systems; the integration of a Phononic band gap structure to such devices would enhance their characteristics and widen their application range. From a fundamental point of view, piezoelectric Phononic Crystals enable experiments in which the sources and detectors of acoustic waves can be embedded with the Phononic Crystal itself, as shown in Fig. 1. The strong anisotropy of acoustic wave propagation inherent to piezoelectric materials, combined with the mixing of shear and longitudinal polarizations, strongly affect wave scattering. Yet it has been demonstrated theoretically that a complete band gap for SAW’s, i.e., for any propagation direction of the impinging wave, can be expected to exist 21 for a square lattice of holes in lithium niobate. A former experimental work has shown the existence of a directional stop band in a silicon Phononic Crystal, with a piezoelectric thin film ensuring surface wave transduction 22. In this Rapid Communication, we report on the fabrication and experimental characterization of a complete band gap square-lattice SAW Phononic Crystal made of void inclusions etched in lithium niobate. The presented results open further prospects for designing a generation of Phononic-Crystal-based acoustic signal processing devices. A finite element model was used to calculate the band diagrams for bulk waves propagating in the plane of the surface. Such a computation is sufficient for design purposes since it was observed that SAW and BAW band gaps coin
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acoustic channel drop tunneling in a Phononic Crystal
Applied Physics Letters, 2005Co-Authors: Yan Pennec, B Djafarirouhani, H Larabi, Sarah Benchabane, J O Vasseur, Abdelkrim Khelif, Abdelkrim Choujaa, Vincent LaudeAbstract:We study both theoretically and experimentally the possibility of resonant tunneling of acoustic waves between two parallel guides created in a Phononic Crystal composed of steel cylinders in water. In the absolute band gap of the Phononic Crystal, ranging from 250to325kHz, a full transmission band exists for propagation inside a straight waveguide. We show that the transfer of a particular wavelength can occur between two parallel waveguides coupled together through an appropriate coupling structure. The latter is composed of isolated cavities interacting with stubs located at the sides of the waveguides.
B Djafarirouhani - One of the best experts on this subject based on the ideXlab platform.
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tunable waveguide and cavity in a Phononic Crystal plate by controlling whispering gallery modes in hollow pillars
Physical Review B, 2016Co-Authors: Yan Pennec, Yabin Jin, Nicolas Fernez, Bernard Bonello, Rayisa P Moiseyenko, Stephanie Hemon, Yongdong Pan, Bernard Bonello, B DjafarirouhaniAbstract:We investigate the properties of a Phononic Crystal plate with hollow pillars and introduce the existence of whispering-gallery modes (WGMs). We show that by tuning the inner radius of the hollow pillar, these modes can merge inside both Bragg and low frequency band gaps, deserving Phononic Crystal and acoustic metamaterial applications. These modes can be used as narrow pass bands for which the quality factor can be greatly enhanced by the introduction of an additional cylinder between the hollow cylinder and the plate. We discuss some functionalities of these confined WGM in both Bragg and low frequency gaps for wavelength division in multiplexer devices using heteroradii pillars introduced into waveguide and cavity structures.
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simultaneous control of the s0 and a0 lamb modes by graded Phononic Crystal plates
Journal of Applied Physics, 2015Co-Authors: Yabin Jin, Yan Pennec, Yongdong Pan, Daniel Torrent, B DjafarirouhaniAbstract:We propose a theory of gradient index devices in plates that allow the simultaneous control of both S0 and A0 Lamb modes. This is in contrast to the existing approaches that are mainly limited to the manipulation of only the lowest A0 modes. These devices are based on Phononic Crystal plates, which are studied in the low frequency (homogenization) limit. We demonstrate a direct relationship between the dispersion relation of these two modes in Phononic Crystal plates that, together with the thickness dependence of the dispersion relation of the A0 mode, allows their simultaneous control. As a matter of illustration, a flat gradient index lens and a circular Luneburg lens are designed by means of the simultaneous variation of the inclusions' radii and the thickness of the plate. Numerical simulations show that the performance of these devices is good for the two modes in a broadband frequency region and that this approach can be used to design more advanced refractive devices for the total control of guide...
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low frequency gaps in a Phononic Crystal constituted of cylindrical dots deposited on a thin homogeneous plate
Physical Review B, 2008Co-Authors: Yan Pennec, B Djafarirouhani, H Larabi, Jero Me Vasseur, A C HladkyhennionAbstract:We investigate theoretically the band structure of a Phononic Crystal of finite thickness constituted of a periodical array of cylindrical dots deposited on a thin plate of a homogeneous material. We show that this structure can display a low-frequency gap, as compared to the acoustic wavelengths in the constituent materials, similarly to the case of locally resonant structures. The opening of this gap requires an appropriate choice of the geometrical parameters, and in particular the thickness of the homogeneous plate and the height of the dots. However, the gap persists for various combinations of the materials constituting the plate and the dots. Besides, the band structure can exhibit one or more higher gaps whose number increases with the height of the cylinders. We discuss the condition to realize waveguiding through a linear defect inside the Phononic Crystal dots. The numerical simulations are performed by using the finite difference time domain and the finite element methods.
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lamb waves in Phononic Crystal slabs with square or rectangular symmetries
Journal of Applied Physics, 2008Co-Authors: Thomas Brunet, B Djafarirouhani, J O Vasseur, Bernard Bonello, A C HladkyhennionAbstract:We report on both numerical and experimental results showing the occurrence of band gaps for Lamb waves propagating in Phononic Crystal plates. The structures are made of centered rectangular and square arrays of holes drilled in a silicon plate. A supercell plane wave expansion method is used to calculate the band structures and to predict the position and the magnitude of the gaps. The band structures of Phononic Crystal slabs are then measured using a laser ultrasonic technique. Lamb waves in the megahertz range and with wave vectors ranging over more than the first two reduced Brillouin zones are investigated.
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absolute forbidden bands and waveguiding in two dimensional Phononic Crystal plates
Physical Review B, 2008Co-Authors: J O Vasseur, B Djafarirouhani, Yan Pennec, P A Deymier, A C HladkyhennionAbstract:We introduce a supercell plane wave expansion (SC-PWE) method for the calculation of elastic band structures of two-dimensional Phononic Crystal plates. We compute the band structure of solid-solid and air-solid two-dimensional Phononic Crystal plates. The air is modeled as a low impedance medium (LIM) with very low density and very high velocities of sound. We investigate the influence of the constituent materials, of the plate thickness, and of the geometry of the array on the band structure. We establish the range of validity of the SC-PWE method in terms of the rate of convergence with respect to the number of plane waves and contrast in physical properties of the matrix and inclusion materials. We show that for high contrast solid-solid Phononic Crystal plates, our SC-PWE method, as other PWE-based methods introduced to date, suffers from convergence difficulties. In the case of air (modeled as the LIM) holes-solid plates, we demonstrate that the SC-PWE method leads to fast convergence for a wide range of values of solid physical properties. With these constituent materials, we find that the largest absolute forbidden bands occur in the band structure of the Phononic Crystal plate provided the thickness of the plate is of the order of magnitude of the periodicity of the array of inclusions. We demonstrate the existence of guided modes in an air-silicon Phononic Crystal plate containing a linear defect.
Zhengyou Liu - One of the best experts on this subject based on the ideXlab platform.
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topological negative refraction of surface acoustic waves in a weyl Phononic Crystal
arXiv: Materials Science, 2018Co-Authors: Chunyin Qiu, Xiangxi Cai, Xiying Fan, Fan Zhang, Zhengyou LiuAbstract:Reflection and refraction occur at interface between two different media. These two fundamental phenomena form the basis of fabricating various wave components. Specifically, refraction, dubbed positive refraction nowadays, appears in the opposite side of the interface normal with respect to the incidence. Negative refraction, emerging in the same side by contrast, has been observed in artificial materials1-5 following a prediction by Veslago6, which has stimulated many fascinating applications such as super-resolution imaging7. Here we report the first discovery of negative refraction of the topological surface arc states of Weyl Crystals, realized for airborne sound in a novel woodpile Phononic Crystal. The interfaces are one-dimensional edges that separate different Crystal facets. By tailoring the surface terminations of such a Weyl Phononic Crystal, open equifrequency contours of surface acoustic waves can be delicately designed to produce the negative refraction, to contrast the positive counterpart realized in the same sample. Strikingly different from the conventional interfacial phenomena, the unwanted reflection can be made forbidden by exploiting the open nature of the surface equifrequency contours, which is a topologically protected surface hallmark of Weyl Crystals8-12.
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topological negative refraction of surface acoustic waves in a weyl Phononic Crystal
Nature, 2018Co-Authors: Chunyin Qiu, Xiangxi Cai, Xiying Fan, Fan Zhang, Zhengyou LiuAbstract:Reflection and refraction of waves occur at the interface between two different media. These two fundamental interfacial wave phenomena form the basis of fabricating various wave components, such as optical lenses. Classical refraction—now referred to as positive refraction—causes the transmitted wave to appear on the opposite side of the interface normal compared to the incident wave. By contrast, negative refraction results in the transmitted wave emerging on the same side of the interface normal. It has been observed in artificial materials1–5, following its theoretical prediction6, and has stimulated many applications including super-resolution imaging7. In general, reflection is inevitable during the refraction process, but this is often undesirable in designing wave functional devices. Here we report negative refraction of topological surface waves hosted by a Weyl Phononic Crystal—an acoustic analogue of the recently discovered Weyl semimetals8–12. The interfaces at which this topological negative refraction occurs are one-dimensional edges separating different facets of the Crystal. By tailoring the surface terminations of the Weyl Phononic Crystal, constant-frequency contours of surface acoustic waves can be designed to produce negative refraction at certain interfaces, while positive refraction is realized at different interfaces within the same sample. In contrast to the more familiar behaviour of waves at interfaces, unwanted reflection can be prevented in our Crystal, owing to the open nature of the constant-frequency contours, which is a hallmark of the topologically protected surface states in Weyl Crystals8–12. Sound waves in a specially designed Crystal undergo ‘topologically protected’ negative refraction, whereby no reflection is allowed, at certain facets of the Crystal and positive refraction at others.
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weyl points and fermi arcs in a chiral Phononic Crystal
Nature Physics, 2018Co-Authors: Xueqin Huang, Zhengyou LiuAbstract:Acoustic Weyl points are realized in a three-dimensional chiral Phononic Crystal that breaks inversion symmetry, with the topological nature of the associate surface states providing robust modes that propagate along only one direction.
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subwavelength imaging of acoustic waves by a canalization mechanism in a two dimensional Phononic Crystal
Applied Physics Letters, 2008Co-Authors: Feiyan Cai, Yiqun Ding, Zhengyou LiuAbstract:In this letter, the subwavelength imaging of acoustic waves is reported based on a mechanism that the evanescent modes of a source are canalized by the Bloch modes of a two-dimensional Phononic Crystal that served as the lens. The Phononic Crystal was designed to have a thickness that meets the condition of Fabry–Perot resonance in order to enhance wave transmission and hence to improve imaging performance. Numerical simulations demonstrated that for a point acoustic source an image as small as 0.16λ can be formed.
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peculiar transmission property of acoustic waves in a one dimensional layered Phononic Crystal
Physica B-condensed Matter, 2007Co-Authors: Degang Zhao, Zhengyou Liu, Wengang Wang, Jing Shi, Weijia WenAbstract:In this article, we report both theoretical calculation and experimental observation of acoustic waves abnormally through a one-dimensional layered transmitted Phononic Crystal at frequencies within the band gap into a material of large acoustic impedance mismatch, with an efficiency as high as unity. The transmission peaks can be interpreted as a result of the interference of acoustic waves reflected from all periodically aligned interfaces. The condition for the appearance of peaks is analyzed in detail and the optimized layer number is given for different configurations.
