Publications
295 results found
Farhat M, Chen PY, Guenneau S, et al., 2016, Cloaking through cancellation of diffusive wave scattering, PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 472, ISSN: 1364-5021
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- Citations: 11
Colombi A, Colquitt D, Roux P, et al., 2016, A seismic metamaterial: the resonant metawedge, Scientific Reports, Vol: 6, ISSN: 2045-2322
Critical concepts from three different fields, elasticity, plasmonics and metamaterials, are brought together to design a metasurface at the geophysical scale, the resonant metawedge, to control seismic Rayleigh waves. Made of spatially graded vertical subwavelength resonators on an elastic substrate, the metawedge can either mode convert incident surface Rayleigh waves into bulk elastic shear waves or reflect the Rayleigh waves creating a "seismic rainbow" effect analogous to the optical rainbow for electromagnetic metasurfaces. Time-domain spectral element simulations demonstrate the broadband efficacy of the metawedge in mode conversion while an analytical model is developed to accurately describe and predict the seismic rainbow effect; allowing the metawedge to be designed without the need for extensive parametric studies and simulations. The efficiency of the resonant metawedge shows that large-scale mechanical metamaterials are feasible, will have application, and that the time is ripe for considering many optical devices in the seismic and geophysical context.
Dupont G, Guenneau S, Kimmoun O, et al., 2016, Cloaking a vertical cylinder via homogenization in the mild-slope equation, JOURNAL OF FLUID MECHANICS, Vol: 796, ISSN: 0022-1120
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- Citations: 20
Colombi A, Guenneau S, Roux P, et al., 2016, Transformation seismology: composite soil lenses for steering surface elastic Rayleigh waves., Scientific Reports, Vol: 6, ISSN: 2045-2322
Metamaterials are artificially structured media that exibit properties beyond those usually encountered in nature. Typically they are developed for electromagnetic waves at millimetric down to nanometric scales, or for acoustics, at centimeter scales. By applying ideas from transformation optics we can steer Rayleigh-surface waves that are solutions of the vector Navier equations of elastodynamics. As a paradigm of the conformal geophysics that we are creating, we design a square arrangement of Luneburg lenses to reroute Rayleigh waves around a building with the dual aim of protection and minimizing the effect on the wavefront (cloaking). To show that this is practically realisable we deliberately choose to use material parameters readily available and this metalens consists of a composite soil structured with buried pillars made of softer material. The regular lattice of inclusions is homogenized to give an effective material with a radially varying velocity profile and hence varying the refractive index of the lens. We develop the theory and then use full 3D numerical simulations to conclusively demonstrate, at frequencies of seismological relevance 3-10 Hz, and for low-speed sedimentary soil (vs: 300-500 m/s), that the vibration of a structure is reduced by up to 6 dB at its resonance frequency.
Alaoui M, Rustomji K, Chang TM, et al., 2016, Cyclic concentrator, carpet cloaks and fisheye lens via transformation plasmonics, JOURNAL OF OPTICS, Vol: 18, ISSN: 2040-8978
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- Citations: 7
Gralak B, Arismendi G, Avril B, et al., 2016, Analysis in temporal regime of dispersive invisible structures designed from transformation optics, PHYSICAL REVIEW B, Vol: 93, ISSN: 2469-9950
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- Citations: 5
Ungureanu B, Achaoui Y, Enoch S, et al., 2016, Auxetic-like metamaterials as novel earthquake protections, EPJ APPLIED METAMATERIALS, Vol: 2, ISSN: 2272-2394
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- Citations: 29
Farhat M, Chen P-Y, Bagci H, et al., 2016, Thermal invisibility based on scattering cancellation and mantle cloaking (vol 5, pg 9876, 2015), SCIENTIFIC REPORTS, Vol: 6, ISSN: 2045-2322
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- Citations: 2
Colombi A, Roux P, Guenneau S, et al., 2016, Forests as a natural seismic metamaterial: Rayleigh wave bandgaps induced by local resonances, Scientific Reports, Vol: 6, ISSN: 2045-2322
We explore the thesis that resonances in trees result in forests acting as locally resonant metamaterials for Rayleigh surface waves in the geophysics context. A geophysical experiment demonstrates that a Rayleigh wave, propagating in soft sedimentary soil at frequencies lower than 150 Hz, experiences strong attenuation, when interacting with a forest, over two separate large frequency bands. This experiment is interpreted using finite element simulations that demonstrate the observed attenuation is due to bandgaps when the trees are arranged at the sub-wavelength scale with respect to the incident Rayleigh wave. The repetitive bandgaps are generated by the coupling of the successive longitudinal resonances of trees with the vertical component of the Rayleigh wave. For wavelengths down to 5 meters, the resulting bandgaps are remarkably large and strongly attenuating when the acoustic impedance of the trees matches the impedance of the soil. Since longitudinal resonances of a vertical resonator are inversely proportional to its length, a man-made engineered array of resonators that attenuates Rayleigh waves at frequency ≤10 Hz could be designed starting from vertical pillars coupled to the ground with longitudinal resonance ≤10 Hz.
Makwana M, Antonakakis T, Maling B, et al., 2016, Wave mechanics in media pinned at bravais lattice points, SIAM Journal on Applied Mathematics, Vol: 76, Pages: 1-26, ISSN: 1095-712X
The propagation of waves through microstructured media with periodically arrangedinclusions has applications in many areas of physics and engineering, stretching from photonic crystalsthrough to seismic metamaterials. In the high-frequency regime, modeling such behavior iscomplicated by multiple scattering of the resulting short waves between the inclusions. Our aimis to develop an asymptotic theory for modeling systems with arbitrarily shaped inclusions locatedon general Bravais lattices. We then consider the limit of pointlike inclusions, the advantage beingthat exact solutions can be obtained using Fourier methods, and go on to derive effective mediumequations using asymptotic analysis. This approach allows us to explore the underlying reasons fordynamic anisotropy, localization of waves, and other properties typical of such systems, and in particulartheir dependence upon geometry. Solutions of the effective medium equations are comparedwith the exact solutions, shedding further light on the underlying physics. We focus on examplesthat exhibit dynamic anisotropy as these demonstrate the capability of the asymptotic theory to pickup detailed qualitative and quantitative features.
Colombi A, Roux P, Colquitt D, et al., 2016, Conversion and reflection of Rayleigh waves with the seismic metawedge, 10th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics (METAMATERIALS), Publisher: IEEE, Pages: 313-315
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- Citations: 1
Ceresoli L, Abdeddaim R, Antonakakis T, et al., 2015, Dynamic effective anisotropy: Asymptotics, simulations, and microwave experiments with dielectric fibers, PHYSICAL REVIEW B, Vol: 92, ISSN: 1098-0121
We investigate dynamic effective anisotropy in photonic crystals (PCs) through a combination of an effective medium theory, which is a high-frequency homogenization (HFH) method explicitly developed to operate for short waves, as well as through numerical simulations and microwave experiments. The HFH yields accurate predictions of the effective anisotropic properties of periodic structures when the wavelength is of comparable order to the pitch of the array; specifically, we investigate a square array of pitch 2 cm consisting of dielectric rods of radius 0.5 cm and refractive index n=6√ within an air matrix. This behaves as an effective medium, with strong artificial anisotropy, at a frequency corresponding to a flat band emerging from a Dirac-like point in transverse magnetic (TM) polarization. At this frequency, highly directive emission is predicted for an electric source placed inside this PC, and this artificial anisotropy can be shown to coincide with a change of character of the underlying effective equation from isotropic to unidirective, with coefficients of markedly different magnitudes appearing in the effective equation tensor. In transverse electric (TE) polarization, we note a second radical change of character of the underlying effective equation, this time from elliptic to hyperbolic, near a frequency at which a saddle point occurs in the corresponding dispersion curves. Delicate microwave experiments are performed in both polarizations for such a PC consisting of 80 rods, and we demonstrate that a directive emission in the form of a + (respectively, an X) is indeed seen experimentally at the predicted frequency 9.5 GHz in TM polarization (respectively, 5.9 GHz in TE polarization). These are clearly dynamic effects since in the quasistatic regime the PC just behaves as an isotropic medium.
Amra C, Petiteau D, Zerrad M, et al., 2015, Analogies between optical propagation and heat diffusion: applications to microcavities, gratings and cloaks, PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 471, ISSN: 1364-5021
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- Citations: 5
Xu J, Jiang X, Fang N, et al., 2015, Molding acoustic, electromagnetic and water waves with a single cloak, SCIENTIFIC REPORTS, Vol: 5, ISSN: 2045-2322
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- Citations: 45
Achaoui Y, Diatta A, Guenneau S, 2015, Steering in-plane shear waves with inertial resonators in platonic crystals, APPLIED PHYSICS LETTERS, Vol: 106, ISSN: 0003-6951
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- Citations: 4
Farhat M, Chen PY, Guenneau S, et al., 2015, Generation of graphene surface plasmons and their applications in beam steering
We propose a novel concept that uses mechanical and electronic properties of graphene to efficiently couple light to surface plasmon polaritons. A graphene-based infrared beam-former based on the concept of surface leaky-wave is also discussed. © OSA 2015.
Guenneau S, Petiteau D, Zerrad M, et al., 2015, Transformed Fourier and Fick equations for the control of heat and mass diffusion, AIP ADVANCES, Vol: 5, ISSN: 2158-3226
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- Citations: 42
Farhat M, Chen P-Y, Bagci H, et al., 2015, Thermal invisibility based on scattering cancellation and mantle cloaking, SCIENTIFIC REPORTS, Vol: 5, ISSN: 2045-2322
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- Citations: 63
Ktorza I, Ceresoli L, Enoch S, et al., 2015, Single frequency microwave cloaking and subwavelength imaging with curved wired media, OPTICS EXPRESS, Vol: 23, Pages: 10319-10326, ISSN: 1094-4087
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- Citations: 3
Colombi A, Roux P, Guenneau S, et al., 2015, Directional cloaking of flexural waves in a plate with a locally resonant metamaterial, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 137, Pages: 1783-1789, ISSN: 0001-4966
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- Citations: 57
Li J, Miao F, Liang Z, et al., 2015, Constructing metamaterials from subwavelength pixels with constant indices product, OPTICS EXPRESS, Vol: 23, Pages: 7140-7151, ISSN: 1094-4087
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- Citations: 1
Dupont G, Kimmoun O, Molin B, et al., 2015, Numerical and experimental study of an invisibility carpet in a water channel, PHYSICAL REVIEW E, Vol: 91, ISSN: 1539-3755
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- Citations: 21
Lefebvre G, Dubois M, Beauvais R, et al., 2015, Experiments on Maxwell's fish-eye dynamics in elastic plates, APPLIED PHYSICS LETTERS, Vol: 106, ISSN: 0003-6951
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- Citations: 18
Colquitt DJ, Craster RV, Antonakakis T, et al., 2015, Rayleigh-Bloch waves along elastic diffraction gratings, PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 471, ISSN: 1364-5021
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- Citations: 24
Dubois M, Bossy E, Enoch S, et al., 2015, Time-Driven Superoscillations with Negative Refraction, PHYSICAL REVIEW LETTERS, Vol: 114, ISSN: 0031-9007
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- Citations: 36
Ungureanu B, Brule S, Achaoui Y, et al., 2015, Mechanical Waves Deflection/Damping With Seismic Metamaterials, 9th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics (METAMATERIALS), Publisher: IEEE, Pages: 310-312
Cherednichenko KD, Cooper S, Guenneau S, 2015, SPECTRAL ANALYSIS OF ONE-DIMENSIONAL HIGH-CONTRAST ELLIPTIC PROBLEMS WITH PERIODIC COEFFICIENTS, MULTISCALE MODELING & SIMULATION, Vol: 13, Pages: 72-98, ISSN: 1540-3459
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- Citations: 10
Farhat M, Chen P-Y, Guenneau S, et al., 2015, Generation of Graphene Surface Plasmons and Their Applications in Beam Steering, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020
Petiteau D, Guenneau S, Bellieud M, et al., 2014, Spectral effectiveness of engineered thermal cloaks in the frequency regime, SCIENTIFIC REPORTS, Vol: 4, ISSN: 2045-2322
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- Citations: 25
Aznavourian R, Guenneau S, 2014, Morphing for faster computations in transformation optics, OPTICS EXPRESS, Vol: 22, Pages: 28301-28315, ISSN: 1094-4087
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- Citations: 5
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