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Journal ArticleDOI

Holey-structured metamaterial lens for subwavelength resolution in ultrasonic characterization of metallic components

01 Jun 2016-Applied Physics Letters (AIP Publishing)-Vol. 108, Iss: 22, pp 224101
TL;DR: In this paper, a holey structured metamaterial lens was used for ultrasonic characterization of subwavelength subsurface defects in metallic components. Butler et al. used numerical simulation to investigate the parameters that can help improve the resolution performance of the metammaterial lens, particularly, the addition of end-conditions.
Abstract: This paper presents the implementation of holey structured metamaterial lens for ultrasonic characterization of subwavelength subsurface defects in metallic components. Experimental results are presented, demonstrating ultrasound-based resolution of side drilled through-holes spaced (λ/5) in an aluminum block. Numerical simulation is then used to investigate the parameters that can help improve the resolution performance of the metamaterial lens, particularly, the addition of end-conditions. This work has important implications for higher resolution ultrasonic imaging in the context of practical non-destructive imaging and non-invasive material diagnostics.
Citations
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Journal ArticleDOI
TL;DR: A comprehensive overview of research on acoustic metamaterials can be found in this article, which highlights prominent future directions in the field, including topological and active metammaterials.

117 citations

Journal ArticleDOI
TL;DR: In this paper, the authors presented the theory, design, simulation, fabrication, and performance of a flexible dual-band MM absorber, which is resonant at microwave frequencies.
Abstract: This paper presents the theory, design, simulation, fabrication, and performance of a flexible dual-band MM absorber, which is resonant at microwave frequencies. The sandwich structure of the MM absorber is composed of the periodic array of the T-shaped metallic patches and a continuous metallic plane, which are separated by a middle flexible dielectric layer. The optimized geometric parameters were obtained by numerous simulations using the full wave finite integration technology of CST 2015. The simulated results indicate that the proposed MM absorber has two distinct absorption peaks at 16.77 and 30.92 GHz with the absorption ratio of 98.7% and 99.3%, respectively. The absorber has a thickness of 0.2403 mm, which is only 1/74 and 1/40 of the wavelength for the resonance frequency of 16.77 and 30.92 GHz. The influence of the material's properties and structural curvature on the absorption performance was investigated by numerous simulations. The proposed MM absorber is highly sensitive to the polarization of the incidence EM wave and has good absorption properties over a large range of the incidence angle for the incidence EM wave. The electric field and surface current distributions at two independent resonance frequencies were analyzed for providing insight into the EM wave absorption mechanism. Simulated results show that two different resonance modes are introduced into the single patterned metallic resonance structure to realize the dual-band performance. The laser ablation process was adopted to fabricate the sample of the proposed absorber. Measured results for the normally incident EM wave show an agreement with the simulated results. The fabricated MM absorber shows significant mechanical flexibility and can easily be conformed to the unusual surfaces such as cylindrical, pyramid, and spherical. Furthermore, this design concept can be extended to the other absorber structure and the other frequency bands, therefore, which can greatly enrich the applications in antenna, sensing, thermal image, and detection. For instance, in the design of projectile-borne conformal antenna array, a flexible ultrathin MM absorber can easily be loaded between the antenna and the projectile body to reduce the radiation interference, weaken the coupling loss, and reduce the RCS.

51 citations


Cites background from "Holey-structured metamaterial lens ..."

  • ...lenses [12], [13], thermal image [14]–[16], and MM absorbers [17], [18]....

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Journal ArticleDOI
TL;DR: In this paper, the authors presented numerically and experimentally the broadband focusing of ultrasonic waves in water with a metasurface lens consisting of an array of deep-subwavelength sized and spaced slots.
Abstract: Focusing of ultrasonic waves in water plays an important role in various scenarios ranging from biomedical imaging to nondestructive testing. Acoustic metasurfaces have been largely explored for acoustic focusing, but they are generally narrowband and mainly implemented for airborne sound because of their structural complexity. Nevertheless, our previous development of metasurfaces provides a great opportunity to solve the challenges. Here, we present numerically and experimentally the broadband focusing of ultrasonic waves in water with a metasurface lens consisting of an array of deep-subwavelength sized and spaced slots. The slot widths of the metasurface are optimized based on microscopic coupled-wave theory. Due to the non-resonant arrangement, the focusing effect is demonstrated over a broad band of frequencies. The metasurface lens with simplicity and an ultra-compact size provides a feasible means for the design of thin and lightweight ultrasonic devices and is suitable for practical applications in biomedical and industrial fields.

47 citations

Journal ArticleDOI
TL;DR: An overview of the design space for metamaterials is provided, with focus on critical factors for scaling of manufacturing in order to fulfill industrial standards.
Abstract: Mechanical metamaterials promise a paradigm shift in materials design, as the classical processing-microstructure-property relationship is no longer exhaustively describing the material properties. The present review article provides an application-centered view on the research field and aims to highlight challenges and pitfalls for the introduction of mechanical metamaterials into technical applications. The main difference compared to classical materials is the addition of the mesoscopic scale into the materials design space. Geometrically designed unit cells, small enough that the metamaterial acts like a mechanical continuum, enabling the integration of a variety of properties and functionalities. This presents new challenges for the design of functional components, their manufacturing and characterization. This article provides an overview of the design space for metamaterials, with focus on critical factors for scaling of manufacturing in order to fulfill industrial standards. The role of experimental and simulation tools for characterization and scaling of metamaterial concepts are summarized and herewith limitations highlighted. Finally, the authors discuss key aspects in order to enable metamaterials for industrial applications and how the design approach has to change to include reliability and resilience.

37 citations

Journal ArticleDOI
TL;DR: The experimental demonstration of deep subwavelength ultrasonic imaging of defects in metallic samples with a feature size of λ/25 using holey-structured metamaterial lenses shows how the extraordinary transmission capacity of holey structured metam material comes about by the coupling of higher frequencies in the incident ultrasonic wave field to resonant modes of the lens.
Abstract: This paper reports the experimental demonstration of deep subwavelength ultrasonic imaging of defects in metallic samples with a feature size of λ/25 using holey-structured metamaterial lenses. Optimal dimensions of the metamaterial’s geometric parameters are determined using numerical simulation and the physics of wave propagation through holey lenses. The paper also shows how the extraordinary transmission capacity of holey structured metamaterials comes about by the coupling of higher frequencies in the incident ultrasonic wave field to resonant modes of the lens.

36 citations


Cites background or methods from "Holey-structured metamaterial lens ..."

  • ...Hole length should be an integer multiple of half the wavelength m(λ/2), as expected based on the Fabry-Perot resonance principle [2, 3]....

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  • ...(Details of the FE modeling approach and implementation can be found in our previous work [2])....

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  • ...Consider the expression for the Transmission Ratio (T) of the metamaterial lens (see [2, 4] for example):...

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References
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Journal ArticleDOI
TL;DR: A composite medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, that exhibits a frequency region in the microwave regime with simultaneously negative values of effective permeability and permittivity varepsilon(eff)(omega).
Abstract: We demonstrate a composite medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous wires, that exhibits a frequency region in the microwave regime with

8,057 citations

Journal ArticleDOI
08 Sep 2000-Science
TL;DR: In this article, a 2-centimeter slab of this composite material is shown to break the conventional mass-density law of sound transmission by one or more orders of magnitude at 400 hertz.
Abstract: We have fabricated sonic crystals, based on the idea of localized resonant structures, that exhibit spectral gaps with a lattice constant two orders of magnitude smaller than the relevant wavelength. Disordered composites made from such localized resonant structures behave as a material with effective negative elastic constants and a total wave reflector within certain tunable sonic frequency ranges. A 2-centimeter slab of this composite material is shown to break the conventional mass-density law of sound transmission by one or more orders of magnitude at 400 hertz.

3,758 citations

Journal ArticleDOI
22 Apr 2005-Science
TL;DR: This work demonstrated sub–diffraction-limited imaging with 60-nanometer half-pitch resolution, or one-sixth of the illumination wavelength, using silver as a natural optical superlens and showed that arbitrary nanostructures can be imaged with good fidelity.
Abstract: Recent theory has predicted a superlens that is capable of producing sub–diffraction-limited images. This superlens would allow the recovery of evanescent waves in an image via the excitation of surface plasmons. Using silver as a natural optical superlens, we demonstrated sub–diffraction-limited imaging with 60-nanometer half-pitch resolution, or one-sixth of the illumination wavelength. By proper design of the working wavelength and the thickness of silver that allows access to a broad spectrum of subwavelength features, we also showed that arbitrary nanostructures can be imaged with good fidelity. The optical superlens promises exciting avenues to nanoscale optical imaging and ultrasmall optoelectronic devices.

3,753 citations

Journal ArticleDOI
TL;DR: In this paper, a review describes the recent progress made in creating nanostructured metamaterials with a negative index at optical wavelengths, and discusses some of the devices that could result from these new materials.
Abstract: Artificially engineered metamaterials are now demonstrating unprecedented electromagnetic properties that cannot be obtained with naturally occurring materials. In particular, they provide a route to creating materials that possess a negative refractive index and offer exciting new prospects for manipulating light. This review describes the recent progress made in creating nanostructured metamaterials with a negative index at optical wavelengths, and discusses some of the devices that could result from these new materials.

2,654 citations