Subwavelength Sound Focusing and Imaging Via Gradient Metasurface-Enabled Spoof Surface Acoustic Wave Modulation

Liu, Tuo; Chen, Fei; Liang, Shanjun; Gao, He; Zhu, Jie

doi:10.1103/physrevapplied.11.034061

Cited by 62 publications

(28 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Acoustic focusing has become a hot research topic due to its potential applications in a variety of scenarios, [1][2][3][4][5][6][7][8][9] such as medical ultrasound, nondestructive detection, and sound communication. In the past few years, the rapid development of sonic crystals [10][11][12][13][14] and acoustic metamaterials [15][16][17][18][19][20][21][22] has provided alternative concepts to design sound focusing devices based on the negative refraction feature.…”

Section: Introductionmentioning

confidence: 99%

Observation of Ultrabroadband Acoustic Focusing Based on V‐Shaped Meta‐Atoms

Zhang

Chen

Qian

et al. 2020

Adv Materials Technologies

View full text Add to dashboard Cite

Acoustic focusing has extensive applications in medical ultrasound and nondestructive detection. The recent rapid development of acoustic metamaterials and metasurfaces has provided various mechanisms for designing advanced focusing lenses. However, the realization of acoustic focusing lenses with ultrabroad bandwidth still remains a challenge. To overcome it, ultrabroadband acoustic focusing lens based on phased unit cells composed of different numbers of same V‐shaped meta‐atoms is theoretically proposed and experimentally realized. By using eight types of unit cells, the fractional bandwidth of the acoustic lens can reach about 1.12 with a high focusing performance. Moreover, based on two types of unit cells with a phase difference of π, the fractional bandwidth of the focusing lens still reaches about 0.76 with the same criteria, showing a high robustness characteristic. The proposed acoustic focusing lenses have the advantages of ultrabroad bandwidths, simple fabrication and assembly, and high robustness, which provide diverse routes to construct ultrabroadband sound devices for medical ultrasound and nondestructive detection.

show abstract

Section: Introductionmentioning

confidence: 99%

Observation of Ultrabroadband Acoustic Focusing Based on V‐Shaped Meta‐Atoms

Zhang

Chen

Qian

et al. 2020

Adv Materials Technologies

View full text Add to dashboard Cite

show abstract

“…Each cell as shown in Fig. 2a can be recognized as a rigid body with a subwavelength center-hollow-hole filled with background medium air [47][48][49][50] , which is designed to couple the SAW modes with surrounding medium. By gradually changing the hole sizes, we can obtain the different surface refractive indexes and SAW impedances without breaking the quasi-periodicity of the whole structure.…”

Section: Resultsmentioning

confidence: 99%

Emitting long-distance spiral airborne sound using low-profile planar acoustic antenna

Gao

et al. 2021

Nat Commun

View full text Add to dashboard Cite

Recent years have witnessed a rapidly growing interest in exploring the use of spiral sound carrying artificial orbital angular momentum (OAM), toward establishing a spiral-wave-based technology that is significantly more efficient in energy or information delivering than the ordinary plane wave technology. A major bottleneck of advancing this technology is the efficient excitation of far-field spiral waves in free space, which is a must in exploring the use of spiral waves for long-distance information transmission and particle manipulation. Here, we report a low-profile planar acoustic antenna to modulate wavefronts emitted from a near-field point source and achieve far-field spiral airborne sound carrying OAM. Using the holographic interferogram as a 2D modulated artificial acoustic impedance metasurface, we show the efficient conversion from the surface wave into the propagating spiral shape beam both numerically and experimentally. The vortex fields with spiral phases originate from the complex inter-modal interactions between cylindrical surface waves and a spatially-modulated impedance boundary condition. This antenna can open new routes to highly integrated spiral sound emitters that are critical for practical acoustic functional devices.

show abstract

“…The planar gradient-index (GRIN) lenses (Lin et al, 2009;Wu et al, 2011) are of particular interest for focusing, collimating, and energy harvesting (Tol et al, 2016). Usually, the displacement field at the focus is only 3~4 times that of the incident wave (Cui et al, 2019;Liu et al, 2019) which suffers from a severe problem, namely a relatively low signal to noise (S/N) ratio.…”

Section: Introductionmentioning

confidence: 99%

“…For example, one possible way to overcome the diffraction limit is to increase the refractive index along the middle of the GRIN lens. Using locally resonant metamaterials to create a large refractive index, either for acoustic (Liu et al, 2019) or for elastic waves (Zhao et al, 2016a), shifts the relevant branches down to low frequency region. This is usually accompanied by strong dispersion so that the effective refractive index may be significantly affected, even by a slight imperfection of the sample (Cui et al, 2019;Liu et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Using locally resonant metamaterials to create a large refractive index, either for acoustic (Liu et al, 2019) or for elastic waves (Zhao et al, 2016a), shifts the relevant branches down to low frequency region. This is usually accompanied by strong dispersion so that the effective refractive index may be significantly affected, even by a slight imperfection of the sample (Cui et al, 2019;Liu et al, 2019). So far, FWHM of ~0.41 times the minimum wavelength λ 0 has been reported in an acoustic metamaterial-based GRIN lens (Liu et al, 2019), when the FWHM is retrieved from the profile of normalized energy density but not from the directly measured acoustic pressure.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Broadband sub-diffraction and ultra-high energy density focusing of elastic waves in planar gradient-index lenses

Zhao

Cui

Bonello

et al. 2021

Journal of the Mechanics and Physics of Solids

View full text Add to dashboard Cite

We demonstrate experimentally and theoretically the broadband sub-diffraction and ultra-high energy density focusing of elastic wave inside planar gradient-index (GRIN) plate lenses based on thickness variation. The full width at half maximum is ~0.40 times the minimum wavelength inside the lens λ 0 or ~1/11 times the incident wavelength in the background plate λ B . We analytically elucidate the underlying physical mechanism as the rapid oscillations in the propagator function at the focal distance. Our design displays several advantages including the broadband sub-diffraction behavior, three-order of magnitudes higher energy intensity at the focal point, and focusing capacity with a narrow transverse width of the lens, over the usual metastructure and/or phononic crystal based GRIN lenses. The broadband sub-diffraction and ultra-high energy density focusing can be used for energy harvesting and signal sensing.

show abstract

Subwavelength Sound Focusing and Imaging Via Gradient Metasurface-Enabled Spoof Surface Acoustic Wave Modulation

Cited by 62 publications

References 61 publications

Observation of Ultrabroadband Acoustic Focusing Based on V‐Shaped Meta‐Atoms

Observation of Ultrabroadband Acoustic Focusing Based on V‐Shaped Meta‐Atoms

Emitting long-distance spiral airborne sound using low-profile planar acoustic antenna

Broadband sub-diffraction and ultra-high energy density focusing of elastic waves in planar gradient-index lenses

Contact Info

Product

Resources

About