scholarly journals Overlapping illusions by transformation optics without any negative refraction material

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Fei Sun ◽  
Sailing He
2021 ◽  
pp. 114-124
Author(s):  
Adrian P Sutton

Metamaterials are composites that have extended the concept of a material. They derive their properties from strong coupling between carefully designed and positioned structural units within them and an incident elastic or electromagnetic wave. They are paragons of materials design. In certain frequency ranges of the incident wave they may display properties that no other materials have ever shown, such as negative refraction. First, an elastic metamaterial demonstrates the principle. Electromagnetic metamaterials have been designed using transformation optics to cloak an object and make it invisible in a certain range of frequencies. The concept of metamaterials has been applied to protect cities and coastal regions from seismic waves and ocean waves.


PIERS Online ◽  
2005 ◽  
Vol 1 (1) ◽  
pp. 34-36 ◽  
Author(s):  
Long Gen Zheng ◽  
Wenxun Zhang

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benoit Tallon ◽  
Artem Kovalenko ◽  
Olivier Poncelet ◽  
Christophe Aristégui ◽  
Olivier Mondain-Monval ◽  
...  

AbstractNegative refraction of acoustic waves is demonstrated through underwater experiments conducted at ultrasonic frequencies on a 3D locally resonant acoustic metafluid made of soft porous silicone-rubber micro-beads suspended in a yield-stress fluid. By measuring the refracted angle of the acoustic beam transmitted through this metafluid shaped as a prism, we determine the acoustic index to water according to Snell’s law. These experimental data are then compared with an excellent agreement to calculations performed in the framework of Multiple Scattering Theory showing that the emergence of negative refraction depends on the volume fraction $$\Phi$$ Φ of the resonant micro-beads. For diluted metafluid ($$\Phi =3\%$$ Φ = 3 % ), only positive refraction occurs whereas negative refraction is demonstrated over a broad frequency band with concentrated metafluid ($$\Phi =17\%$$ Φ = 17 % ).


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4018
Author(s):  
Hao Song ◽  
Xiaodong Ding ◽  
Zixian Cui ◽  
Haohao Hu

Acoustic metamaterials are materials with artificially designed structures, which have characteristics that surpass the behavior of natural materials, such as negative refraction, anomalous Doppler effect, plane focusing, etc. This article mainly introduces and summarizes the related research progress of acoustic metamaterials in the past two decades, focusing on meta-atomic acoustic metamaterials, metamolecular acoustic metamaterials, meta-atomic clusters and metamolecule cluster acoustic metamaterials. Finally, the research overview and development trend of acoustic metasurfaces are briefly introduced.


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