Journal ArticleDOI
Reduced acoustic cloaks based on temperature gradients
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In this paper, a reduced acoustic cloak that uses a temperature gradient in order to obtain sound speeds larger than in air is presented. But the cloaking behavior is different from that predicted for perfect cloaking.Abstract:
This letter presents the design of a reduced acoustic cloak that uses a temperature gradient in order to obtain sound speeds larger than in air. The cloak consists of a circular acoustic crystal made of ten concentric layers of rigid cylinders whose surfaces are heated or cooled in order to get the temperature gradient needed for cloaking behavior. The total pressure field produced by the scattering of sound waves impinging this complex structure is computed and it is shown how acoustic waves are bent in a way similar to that predicted for perfect cloaking devices.read more
Citations
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Journal ArticleDOI
Metamaterials beyond electromagnetism
TL;DR: This review includes homogeneous metamaterials as well as intentionally inhomogeneous meetamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics, and gives an overview on the current state of the art regarding theory and experiment from the viewpoint of an experimentalist.
Journal ArticleDOI
Pentamode Metamaterials with Independently Tailored Bulk Modulus and Mass Density
TL;DR: In this article, a class of three-dimensional linear elastic metamaterials for which the effective bulk modulus and mass density can be adjusted independently over a large range is presented.
Journal ArticleDOI
Broadband Acoustic Cloaking within an Arbitrary Hard Cavity
Weiwei Kan,Weiwei Kan,Victor M. García-Chocano,Francisco Cervera,Bin Liang,Bin Liang,Xin-Ye Zou,Lei-lei Yin,Jianchun Cheng,Jianchun Cheng,José Sánchez-Dehesa +10 more
TL;DR: In this paper, the authors employ transformation acoustics to design and demonstrate a broadband, three-dimensional cloak that renders an object in an open cavity with hard boundaries nearly undetectable.
Journal ArticleDOI
An experimental acoustic cloak for generating virtual images
TL;DR: In this article, a two-dimensional acoustic cloak is realized to generate virtual image in air, which is designed to make the backscattering characteristics of a quadrangular prism the same as that of a plate based on transformation acoustics.
Journal ArticleDOI
Acoustic focusing by an array of heat sources in air
Yong Ge,Hong-xiang Sun,Hong-xiang Sun,Hong-xiang Sun,Chen Liu,Jiao Qian,Shouqi Yuan,Jian-ping Xia,Yi-jun Guan,Shu-yi Zhang +9 more
TL;DR: In this paper, a broadband acoustic focusing lens comprising 20 heat sources of different temperatures, 10 on each side of the array, in air is reported, which is attributed to temperature gradients inducing the desired refractive index in one medium (air) and to continuously changing acoustic impedance, which avoids any acoustic impedance difference that would occur between a lens and air.
References
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Journal ArticleDOI
Metamaterial Electromagnetic Cloak at Microwave Frequencies
David Schurig,Jack J. Mock,B.J. Justice,Steven A. Cummer,John B. Pendry,Anthony F. Starr,David R. Smith +6 more
TL;DR: This work describes here the first practical realization of a cloak of invisibility, constructed with the use of artificially structured metamaterials, designed for operation over a band of microwave frequencies.
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One path to acoustic cloaking
Steven A. Cummer,David Schurig +1 more
TL;DR: In this paper, it was shown that the acoustic equations in a fluid are identical in form to the single polarization Maxwell equations via a variable exchange that also preserves boundary conditions, and the existence of transformation-type solutions for the 2D acoustic equations with anisotropic mass via time harmonic simulations of acoustic cloaking.
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On cloaking for elasticity and physical equations with a transformation invariant form
TL;DR: In this paper, the form of the conventional elastodynamic equations changes under curvilinear transformations, and they are mapped to a more general form in which the density is anisotropic and additional terms appear which couple the stress not only with the strain but also with the velocity.
Journal ArticleDOI
Broadband acoustic cloak for ultrasound waves.
TL;DR: The experiment clearly shows that the acoustic cloak can effectively bend the ultrasound waves around the hidden object, with reduced scattering and shadow, and indicates that this design approach should be scalable to different acoustic frequencies and offers the possibility for a variety of devices based on coordinate transformation.
Journal ArticleDOI
Experimental demonstration of an acoustic magnifying hyperlens.
TL;DR: The experimental demonstration of an acoustic hyperlens that magnifies subwavelength objects by gradually converting evanescent components into propagating waves and achieves deep-subwavelength resolution with low loss over a broad frequency bandwidth is reported.