Broadband quasi perfect absorption using chirped multi-layer porous materials

Jiménez, Noé; Romero‐García, Vicente; Cebrecos, Alejandro; Picó, Rubén; Sánchez‐Morcillo, Víctor J.; Garcı́a-Raffi, L. M.

doi:10.1063/1.4971274

Cited by 27 publications

(13 citation statements)

References 25 publications

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“…This enhancement is attracting most of the attention as it can positively impact technologies for energy harvesting, sensing and absorption of waves in electromagnetism 23, 24 , acoustics 25, 26 , and, as discussed here, elastodynamics 1 .…”

Section: Introductionmentioning

confidence: 99%

Enhanced sensing and conversion of ultrasonic Rayleigh waves by elastic metasurfaces

Colombi

Ageeva

Smith

et al. 2017

Sci Rep

101

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Recent years have heralded the introduction of metasurfaces that advantageously combine the vision of sub-wavelength wave manipulation, with the design, fabrication and size advantages associated with surface excitation. An important topic within metasurfaces is the tailored rainbow trapping and selective spatial frequency separation of electromagnetic and acoustic waves using graded metasurfaces. This frequency dependent trapping and spatial frequency segregation has implications for energy concentrators and associated energy harvesting, sensing and wave filtering techniques. Different demonstrations of acoustic and electromagnetic rainbow devices have been performed, however not for deep elastic substrates that support both shear and compressional waves, together with surface Rayleigh waves; these allow not only for Rayleigh wave rainbow effects to exist but also for mode conversion from surface into shear waves. Here we demonstrate experimentally not only elastic Rayleigh wave rainbow trapping, by taking advantage of a stop-band for surface waves, but also selective mode conversion of surface Rayleigh waves to shear waves. These experiments performed at ultrasonic frequencies, in the range of 400–600 kHz, are complemented by time domain numerical simulations. The metasurfaces we design are not limited to guided ultrasonic waves and are a general phenomenon in elastic waves that can be translated across scales.

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Section: Introductionmentioning

confidence: 99%

Enhanced sensing and conversion of ultrasonic Rayleigh waves by elastic metasurfaces

Colombi

Ageeva

Smith

et al. 2017

Sci Rep

101

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“…Structures called chirped or graded materials are widely used due to their special properties allowing manipulation of the propagating wave. They are used for focusing, trapping, bending waves, opening of wide full band gaps, controlling reflection in the spatial dispersion beams [11].…”

Section: Introductionmentioning

confidence: 99%

Transmission Properties of Two-Dimensional Chirped Phononic Crystal

2019

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The mechanical wave transmission was investigated by a two-dimensional structure made of rods with a periodic arrangement-as the base structure. Compared structures had the same network constant in the direction perpendicular to the propagation of the acoustic wave, while the distances of subsequent layers of phononic crystal increased by a certain factor k. Depending on parameter k, chirped phononic crystal transmission properties were tested. The numerical analysis uses the finite difference time domain algorithm. The discrete Fourier transform allowed to determine the frequency characteristics of the tested systems. In order to verify numerical data, the experimental data was analyzed.

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“…However, it is in general difficult to satisfy such condition for airborne sound. Broadband perfect sound absorption has been realized by slow sound phenomena in closed 6 , 14 – 26 and non-closed 3 – 5 , 27 – 31 sub-wavelength waveguides. If the leakage of the energy and the inherent loss of the device at the resonance frequency are balanced, critical coupling between the system and the environment is achieved 32 , 33 .…”

Section: Introductionmentioning

confidence: 99%

Coupled Resonators for Sound Trapping and Absorption

Jahdali

2018

Sci Rep

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The leakage of sound waves in a resonance based rainbow trapping device prevents the sound wave being trapped in a specific location. In this study, we report a design of sound trapping device based on coupled Helmholtz resonators, loaded to an air waveguide, which can effectively tackle the wave leakage issue. We show that coupled resonators structure can generate dips in the transmission spectrum by an analytical model derived from Newton’s second law and numerical analysis based on finite-element method. An effective medium theory is derived, which shows that coupled resonators cause a negative effective bulk modulus near the resonance frequency and induce flat bands that give rise to the confinement of the incoming wave inside the resonators. We compute the transmission spectra and band diagram from the effective medium theory, which are consistent with the simulation results. Trapping and high absorption of sound wave energy are demonstrated with our designed device.

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Broadband quasi perfect absorption using chirped multi-layer porous materials

Cited by 27 publications

References 25 publications

Enhanced sensing and conversion of ultrasonic Rayleigh waves by elastic metasurfaces

Enhanced sensing and conversion of ultrasonic Rayleigh waves by elastic metasurfaces

Transmission Properties of Two-Dimensional Chirped Phononic Crystal

Coupled Resonators for Sound Trapping and Absorption

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