A review of acoustic Luneburg lens: Physics and applications

Zhao, Liuxian; Bi, Chuan‐Xing; Huang, Haihong; Liu, Qimin; Tian, Zhenhua

doi:10.1016/j.ymssp.2023.110468

Cited by 9 publications

(4 citation statements)

References 72 publications

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“…This leads to a plane wave like behavior in the crystal and results in the wave leaving the crystal with a flat phase profile. This is, in effect, a collimation experiment where the compact source is transformed into a plane wave similar to the Luneburg lens based on index gradient media [38][39][40][41][42][43][44][45][46][47]. The collimation effect is related to the excitation of a single Bloch mode of the crystal leading to a plane wave like propagation in the crystal as illustrated in figure 4.…”

Section: Interpretation Of Collimated Beam Forming At 142 Khz With Hi...mentioning

confidence: 99%

Collimated beam formation in 3D acoustic sonic crystals

Vanel,

Dubois,

Tronche

et al. 2024

New J. Phys.

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We demonstrate strongly collimated beam forming, at audible frequencies, in a three-dimensional acoustic phononic crystal where the wavelength is commensurate with the crystal elements; the crystal is a seemingly simple rectangular cuboid constructed from closely-spaced spheres, and yet demonstrates rich wave phenomena acting as a canonical three-dimensional metamaterial. We employ theory, numericalsimulation and experiments to design and interpret this collimated beam phenomenon and use a crystal consisting of a finite rectangular cuboid array of 4×10×10 polymer spheres 1.38 cm in diameter in air, arranged in a primitive cubic cell with the centre-to-centrespacing of the spheres, i.e. the pitch, as 1.5 cm. Collimation effects are observed in the time domain for chirps with central frequencies at 14.2 kHz and 18 kHz, and we deployed a laser feedback interferometer or Self-Mixing Interferometer (SMI) – a recently proposed technique to observe complex acoustic fields – that enables experimental visualisation of the pressure field both within the crystal and outside of thecrystal. Numerical exploration using a higher-order multi-scale finite element method designed for the rapid and detailed simulation of 3D wave physics further confirms these collimation effects and cross-validates with the experiments. Interpretation follows using High Frequency Homogenization and Bloch analysis whereby the different origin of the collimation at these two frequencies is revealed by markedly differentisofrequency surfaces of the sonic crystal.

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Section: Interpretation Of Collimated Beam Forming At 142 Khz With Hi...mentioning

confidence: 99%

Collimated beam formation in 3D acoustic sonic crystals

Vanel,

Dubois,

Tronche

et al. 2024

New J. Phys.

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“…The Luneburg lens was also applied to create multiple beams in direction finding applications in many RF/mm-wave a) Electronic mail: cxbi@hfut.edu.cn frequency bands Biswas, 2019;Chou et al, 2019;Li et al, 2019;Biswas and Mirotznik, 2020;Elmansouri and Filipovic, 2022). The Luneburg lens has been continuously receiving attention in the acoustics field (Torrent et al, 2014;Wang et al, 2015;Fu et al, 2018;Park and Lee, 2018;Zhao et al, 2020;Zhao and Yu, 2020a,b;Chen et al, 2021;Zhao et al, 2023a;Zhao et al, 2023b;Zhao et al, 2023c;Zhao et al, 2023d) with the development of phononic crystals (Peng et al, 2010;Wu and Chen, 2011;Chen et al, 2014;Jin et al, 2019;Zhao and Zhou, 2019; in recent years. One exceptional characteristic of ALL is that the lens can detect the directivities of acoustic sources based on the focal positions.…”

Section: Introductionmentioning

confidence: 99%

Passive directivity detection of acoustic sources based on acoustic Luneburg lens

Zhao

Tang

Liu

et al. 2023

The Journal of the Acoustical Society of America

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This article reports an acoustic Luneburg lens (ALL) design with graded refractive index for passive directivity detection of acoustic sources. The refractive index profile of the lens is realized based on square pillars with graded variation of their dimensions. Numerical and experimental studies are conducted to investigate the performance of directivity detection. The results demonstrate that the lens designed and developed in this study is capable of precisely detecting the directivity of one acoustic source. Furthermore, the directivities of two acoustic sources can also be detected with a resolution of 15°. In addition, different methods are investigated, including introducing phase difference by tuning input signals or moving ALL, and increasing the aperture size of ALL, to improve the resolution of dual sources directivity detection.

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“…Due to the universality of its physical concept, Luneburg lenses are used for the manipulation and energy harvesting of electromagnetic, acoustic, and plate waves. [19][20][21][22][23][24] More recently, Yu et al 25) developed a way to manipulate acoustic waves in water by designing an underwater acoustic Luneburg lens with a broad work range from 160 to 210 kHz. Zhao et al 26) improved the classical Luneburg lens to design a three-foci and three-beam elastic lens with continuous changing of thickness defined in a thin plate structure to control flexural waves.…”

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confidence: 99%

“…Zhao et al 26) improved the classical Luneburg lens to design a three-foci and three-beam elastic lens with continuous changing of thickness defined in a thin plate structure to control flexural waves. Zhao et al 24,27) explored a broadband double-foci generalized Luneburg lens to manipulate acoustic waves, for achieving an ultralong focal region between the two acoustic foci. Most studies focused on bulk acoustic wave focusing.…”

mentioning

confidence: 99%

Broadband focusing of seismic Rayleigh waves by Luneburg lens in the semi-infinite soil

Tang,

Linghu,

Yang

et al. 2023

Appl. Phys. Express

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We propose a Luneburg lens for focusing the seismic Rayleigh waves composed of blind holes with varying radii in a semi-infinite soil substrate. Luneburg lens has a broadband property of achieving a focusing effect from 6Hz to 9 Hz. It can enhance the wave amplitude by almost 4 times at the focus, and concentrate about 71% of the incident seismic wave energy in the focal area. And its full width at half maximum (FWHM) can reach a minimum of 0.7λ. The effect of wavefront conversion of Lunenburg lens from a cylindrical wave to a plane wave is effectively demonstrated.

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A review of acoustic Luneburg lens: Physics and applications

Cited by 9 publications

References 72 publications

Collimated beam formation in 3D acoustic sonic crystals

Collimated beam formation in 3D acoustic sonic crystals

Passive directivity detection of acoustic sources based on acoustic Luneburg lens

Broadband focusing of seismic Rayleigh waves by Luneburg lens in the semi-infinite soil

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