Focusing Ultrasound with an Acoustic Metamaterial Network

Shu, Zhang; Yin, Leilei; Fang, Nicholas X.

doi:10.1103/physrevlett.102.194301

Cited by 530 publications

(307 citation statements)

References 43 publications

(69 reference statements)

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“…An LHM can display a series of unique "reversed" characteristics, including negative refraction, sub-wavelength focusing, sub-wavelength imaging, and invisibility cloaking. [6][7][8][9][10][11][12] Novel phenomena have changed our knowledge of traditional materials such that various new applications previously unimagined can now be achieved.…”

mentioning

confidence: 99%

Flute-model acoustic metamaterials with simultaneously negative bulk modulus and mass density

Zeng

Chen

et al. 2013

Solid State Communications

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We experimentally constructed a three-dimensional flute-model "molecular" structure acoustic metamaterial (AM) from a periodic array of perforated hollow steel tubes (PHSTs) and investigated its transmission and reflection behaviors in an impedance tube system. The AM exhibited a transmission peak and an inverse phase, thus exhibiting the local resonance of the PHSTs. Based on the homogeneous media theory, the effective bulk modulus and mass density of the AM were calculated to be simultaneously negative; the refractive index was also negative. PHST AM slab focusing experiments showed that the medium with a resonant structure exhibited a distinct metamaterial property.

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confidence: 99%

Flute-model acoustic metamaterials with simultaneously negative bulk modulus and mass density

Zeng

Chen

et al. 2013

Solid State Communications

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“…The same considerations apply to the focusing of acoustic waves by a doublenegative (i.e. negative effective density and elastic modulus) slab of material [11].…”

Section: Introductionmentioning

confidence: 98%

Upholding the diffraction limit in the focusing of light and sound

Maznev

Wright

2017

Wave Motion

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The concept of the diffraction limit put forth by Ernst Abbe and others has been an important guiding principle limiting our ability to tightly focus classical waves, such as light and sound, in the far field. In the past decade, numerous reports have described focusing or imaging with light and sound 'below the diffraction limit'. We argue that the diffraction limit defined in a reasonable way, for example in terms of the upper bound on the wave numbers corresponding to the spatial Fourier components of the intensity profile, or in terms of the spot size into which at least 50% of the incident power can be focused, still stands unbroken to this day. We review experimental observations of 'subwavelength' or 'sub-diffraction-limit' focusing, which can be principally broken down into three broad categories: (i) 'super-resolution', i.e. the technique based on the modification of the pupil of the optical system to reduce the width of the central maximum in the intensity distribution at the expense of increasing side bands; (ii) solid immersion lenses, making use of metamaterials with a high effective index; (iii) concentration of intensity by a subwavelength structure such as an antenna. Even though a lot of interesting work has been done along these lines, none of the hitherto performed experiments violated the sensibly defined diffraction limit.

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“…The determination of the effective parameters of metamaterials has been researched by a series of works, [27][28][29] for example, negative parameters have been shown to exist in resonant composites, 30 concentric alternating layered thin materials and perforated plastic plates have been shown the inhomogeneous and anisotropic characteristics. 16,24,31 But for the design of the cloak, it is also difficult to determine the size of the microstructure and its effective parameters quickly and precisely.…”

Section: Introductionmentioning

confidence: 99%

Design and analysis of the trapeziform and flat acoustic cloaks with controllable invisibility performance in a quasi-space

et al. 2015

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We present the design, implementation and detailed performance analysis for a class of trapeziform and flat acoustic cloaks. An effective large invisible area is obtained compared with the traditional carpet cloak. The cloaks are realized with homogeneous metamaterials which are made of periodic arrangements of subwavelength unit cells composed of steel embedded in air. The microstructures and its effective parameters of the cloaks are determined quickly and precisely in a broadband frequency range by using the effective medium theory and the proposed parameters optimization method. The invisibility capability of the cloaks can be controlled by the variation of the key design parameters and scale factor which are proved to have more influence on the performance in the near field than that in the far field. Different designs are suitable for different application situations. Good cloaking performance demonstrates that such a device can be physically realized with natural materials which will greatly promote the real applications of invisibility cloak.

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Focusing Ultrasound with an Acoustic Metamaterial Network

Cited by 530 publications

References 43 publications

Flute-model acoustic metamaterials with simultaneously negative bulk modulus and mass density

Flute-model acoustic metamaterials with simultaneously negative bulk modulus and mass density

Upholding the diffraction limit in the focusing of light and sound

Design and analysis of the trapeziform and flat acoustic cloaks with controllable invisibility performance in a quasi-space

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