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https://www.readbyqxmd.com/read/27935191/double-negative-mechanical-metamaterials-displaying-simultaneous-negative-stiffness-and-negative-poisson-s-ratio-properties
#1
Trishan A M Hewage, Kim L Alderson, Andrew Alderson, Fabrizio Scarpa
No abstract text is available yet for this article.
December 2016: Advanced Materials
https://www.readbyqxmd.com/read/27934083/self-assembled-nanostructured-tunable-metamaterials-via-spinodal-decomposition
#2
Zuhuang Chen, Xi Wang, Yajun Qi, Sui Yang, Julio A N T Soares, Brent A Apgar, Ran Gao, Ruijuan Xu, Yeonbae Lee, Xiang Zhang, Jie Yao, Lane W Martin
Self-assembly via nanoscale phase separation offers an elegant route to fabricate nanocomposites with physical properties unattainable in single-component systems. One important class of nanocomposites are optical metamaterials which exhibit exotic properties and lead to opportunities for agile control of light propagation. Such metamaterials are typically fabricated via expensive and hard-to-scale top-down processes requiring precise integration of dissimilar materials. In turn, there is a need for alternative, more efficient routes to fabricate large-scale metamaterials for practical applications with deep-subwavelength resolution...
November 22, 2016: ACS Nano
https://www.readbyqxmd.com/read/27929132/three-dimensional-simultaneous-arbitrary-way-orbital-angular-momentum-generator-based-on-transformation-optics
#3
Chen Zhang, Li Deng, Wei Jun Hong, Wei Xiang Jiang, Jian Feng Zhu, Mi Zhou, Ling Wang, Shu Fang Li, Biao Peng
In wireless communications, people utilize the technology of diversity against multipath fading, so as to improve the reliability of communication equipment. One of the long-standing problems in diversity antennas is the limited number of diversity in a certain space. In this paper, we provide a solution to this issue by a three-dimensional (3D) simultaneous arbitrary-way orbital angular momentum (OAM) generator (3D SAWOG) based on transformation optics. The proposed 3D SAWOG consists of a metamaterial block and a group of transformation cylinders, by which arbitrary-way planar wavefronts can be converted to helical wavefronts with various topological charges simultaneously...
December 8, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27929038/designing-multipolar-resonances-in-dielectric-metamaterials
#4
Nikita A Butakov, Jon A Schuller
Dielectric resonators form the building blocks of nano-scale optical antennas and metamaterials. Due to their multipolar resonant response and low intrinsic losses they offer design flexibility and high-efficiency performance. These resonators are typically described in terms of a spherical harmonic decomposition with Mie theory. In experimental realizations however, a departure from spherical symmetry and the use of high-index substrates leads to new features appearing in the multipolar response. To clarify this behavior, we present a systematic experimental and numerical characterization of Silicon disk resonators...
December 8, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27924937/deep-sub-wavelength-nanofocusing-of-uv-visible-light-by-hyperbolic-metamaterials
#5
Minkyung Kim, Sunae So, Kan Yao, Yongmin Liu, Junsuk Rho
Confining light into a sub-wavelength area has been challenging due to the natural phenomenon of diffraction. In this paper, we report deep sub-wavelength focusing via dispersion engineering based on hyperbolic metamaterials. Hyperbolic metamaterials, which can be realized by alternating layers of metal and dielectric, are materials showing opposite signs of effective permittivity along the radial and the tangential direction. They can be designed to exhibit a nearly-flat open isofrequency curve originated from the large-negative permittivity in the radial direction and small-positive one in the tangential direction...
December 7, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27917909/apparent-negative-reflection-with-the-gradient-acoustic-metasurface-by-integrating-supercell-periodicity-into-the-generalized-law-of-reflection
#6
Bingyi Liu, Wenyu Zhao, Yongyuan Jiang
As the two dimensional version of the functional wavefront manipulation metamaterial, metasurface has become a research hot spot for engineering the wavefront at will with a subwavelength thickness. The wave scattered by the gradient metasurface, which is composed by the periodic supercells, is governed by the generalized Snell's law. However, the critical angle that derived from the generalized Snell's law circles the domain of the incident angles that allow the occurrence of the anomalous reflection and refraction, and no free space scattering waves could exist when the incident angle is beyond the critical angle...
December 5, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27911564/observation-of-collective-coupling-between-an-engineered-ensemble-of-macroscopic-artificial-atoms-and-a-superconducting-resonator
#7
Kosuke Kakuyanagi, Yuichiro Matsuzaki, Corentin Déprez, Hiraku Toida, Kouichi Semba, Hiroshi Yamaguchi, William J Munro, Shiro Saito
The hybridization of distinct quantum systems is now seen as an effective way to engineer the properties of an entire system leading to applications in quantum metamaterials, quantum simulation, and quantum metrology. Recent improvements in both fabrication techniques and qubit design have allowed the community to consider coupling large ensembles of artificial atoms, such as superconducting qubits, to a resonator. Here, we demonstrate the coherent coupling between a microwave resonator and a macroscopic ensemble composed of several thousand superconducting flux qubits, where we observe a large dispersive frequency shift in the spectrum of 250 MHz...
November 18, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27910853/holographic-free-electron-light-source
#8
Guanhai Li, Brendan P Clarke, Jin-Kyu So, Kevin F MacDonald, Nikolay I Zheludev
Recent advances in the physics and technology of light generation via free-electron proximity and impact interactions with nanostructures (gratings, photonic crystals, nano-undulators, metamaterials and antenna arrays) have enabled the development of nanoscale-resolution techniques for such applications as mapping plasmons, studying nanoparticle structural transformations and characterizing luminescent materials (including time-resolved measurements). Here, we introduce a universal approach allowing generation of light with prescribed wavelength, direction, divergence and topological charge via point-excitation of holographic plasmonic metasurfaces...
December 2, 2016: Nature Communications
https://www.readbyqxmd.com/read/27910073/a-polarization-dependent-normal-incident-quantum-cascade-detector-enhanced-via-metamaterial-resonators
#9
Lei Wang, Shen-Qiang Zhai, Feng-Jiao Wang, Jun-Qi Liu, Shu-Man Liu, Ning Zhuo, Chuan-Jin Zhang, Li-Jun Wang, Feng-Qi Liu, Zhan-Guo Wang
The design, fabrication, and characterization of a polarization-dependent normal incident quantum cascade detector coupled via complementary split-ring metamaterial resonators in the infrared regime are presented. The metamaterial structure is designed through three-dimensional finite-difference time-domain method and fabricated on the top metal contact, which forms a double-metal waveguide together with the metallic ground plane. With normal incidence, significant enhancements of photocurrent response are obtained at the metamaterial resonances compared with the 45° polished edge coupling device...
December 2016: Nanoscale Research Letters
https://www.readbyqxmd.com/read/27908040/modeling-and-design-of-two-dimensional-membrane-type-active-acoustic-metamaterials-with-tunable-anisotropic-density
#10
Ahmed Allam, Adel Elsabbagh, Wael Akl
A two-dimensional active acoustic metamaterial with controllable anisotropic density is introduced. The material consists of composite lead-lead zirconate titanate plates clamped to an aluminum structure with air as the background fluid. The effective anisotropic density of the material is controlled, independently for two orthogonal directions, by means of an external static electric voltage signal. The material is used in the construction of a reconfigurable waveguide capable of controlling the direction of the acoustic waves propagating through it...
November 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27908026/resonant-metalenses-for-flexural-waves-in-plates
#11
Andrea Colombi
The dispersion curves of a cluster of closely spaced rods supported by a thin plate are characterised by subwavelength bandgaps and slow group velocities induced by local resonance effects. A recent analytical study [Williams, Roux, Rupin, and Kuperman (2015). Phys. Rev. B 91, 104307], has shown how the slow velocity branch depends, amongst other parameters, on the height of the rods that make up the cluster. Such metamaterial, offering easy-to-tune spatial velocity gradients, is a perfect candidate for building gradient index lenses such as Luneburg, Maxwell, and 90° rotating...
November 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27906376/spin-hall-effect-of-transmitted-light-in-a-three-layer-waveguide-with-lossy-epsilon-near-zero-metamaterial
#12
Tingting Tang, Jie Li, Yanfen Zhang, Chaoyang Li, Li Luo
We study spin Hall effect (SHE) of transmitted light in a three-layer waveguide with epsilon-near-zero (ENZ) metamaterial. As the increased loss of anisotropic ENZ metamaterial brings decreased propagation loss for oblique incidence, the transmission of incident light is enhanced which induces a different distribution of transverse shift peaks. Based on simulation results, the influences of ENZ permittivity components and thickness as well as gold layer thickness on transverse shift of left-circularly polarized light in ENZ/Au/ENZ waveguide are analyzed...
November 28, 2016: Optics Express
https://www.readbyqxmd.com/read/27897165/nonreciprocity-and-magnetic-free-isolation-based-on-optomechanical-interactions
#13
Freek Ruesink, Mohammad-Ali Miri, Andrea Alù, Ewold Verhagen
Nonreciprocal components, such as isolators and circulators, provide highly desirable functionalities for optical circuitry. This motivates the active investigation of mechanisms that break reciprocity, and pose alternatives to magneto-optic effects in on-chip systems. In this work, we use optomechanical interactions to strongly break reciprocity in a compact system. We derive minimal requirements to create nonreciprocity in a wide class of systems that couple two optical modes to a mechanical mode, highlighting the importance of optically biasing the modes at a controlled phase difference...
November 29, 2016: Nature Communications
https://www.readbyqxmd.com/read/27893722/valley-photonic-crystals-for-control-of-spin-and%C3%A2-topology
#14
Jian-Wen Dong, Xiao-Dong Chen, Hanyu Zhu, Yuan Wang, Xiang Zhang
Photonic crystals offer unprecedented opportunity for light manipulation and applications in optical communication and sensing. Exploration of topology in photonic crystals and metamaterials with non-zero gauge field has inspired a number of intriguing optical phenomena such as one-way transport and Weyl points. Recently, a new degree of freedom, valley, has been demonstrated in two-dimensional materials. Here, we propose a concept of valley photonic crystals with electromagnetic duality symmetry but broken inversion symmetry...
November 28, 2016: Nature Materials
https://www.readbyqxmd.com/read/27886279/slowing-down-light-using-a-dendritic-cell-cluster-metasurface-waveguide
#15
Z H Fang, H Chen, F S Yang, C R Luo, X P Zhao
Slowing down or even stopping light is the first task to realising optical information transmission and storage. Theoretical studies have revealed that metamaterials can slow down or even stop light; however, the difficulty of preparing metamaterials that operate in visible light hinders progress in the research of slowing or stopping light. Metasurfaces provide a new opportunity to make progress in such research. In this paper, we propose a dendritic cell cluster metasurface consisting of dendritic structures...
November 25, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27886230/controlling-the-electromagnetic-field-confinement-with-metamaterials
#16
Jordi Bonache, Gerard Zamora, Ferran Paredes, Simone Zuffanelli, Pau Aguilà, Ferran Martín
The definition of a precise illumination region is essential in many applications where the electromagnetic field should be confined in some specific volume. By using conventional structures, it is difficult to achieve an adequate confinement distance (or volume) with negligible levels of radiation leakage beyond it. Although metamaterial structures and metasurfaces are well-known to provide high controllability of their electromagnetic properties, this feature has not yet been applied to solve this problem...
November 25, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27886208/flexible-controls-of-scattering-clouds-using-coding-metasurfaces
#17
Shuo Liu, Tie Jun Cui
Metamaterials or metasurfaces have been designed to precisely manipulate the scattering at every angle. Here, we propose to control the probability of random scattering appearing in the desired range of angles, which is defined in this letter as scattering cloud. We present a controllable random metasurface by simply adding a random coding sequence to gradient coding sequence. It is shown that the direction and size of the scattering cloud can be arbitrarily engineered. We demonstrate the exotic behavior of the scattering cloud by making an analogy to the electron cloud in quantum mechanics...
November 25, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27885268/loss-induced-enhanced-transmission-in-anisotropic-density-near-zero-acoustic-metamaterials
#18
Chen Shen, Yun Jing
Anisotropic density-near-zero (ADNZ) acoustic metamaterials are investigated theoretically and numerically in this paper and are shown to exhibit extraordinary transmission enhancement when material loss is induced. The enhanced transmission is due to the enhanced propagating and evanescent wave modes inside the ADNZ medium thanks to the interplay of near-zero density, material loss, and high wave impedance matching in the propagation direction. The equi-frequency contour (EFC) is used to reveal whether the propagating wave mode is allowed in ADNZ metamaterials...
November 25, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27883052/electrical-switching-in-semiconductor-metal-self-assembled-vo2-disordered-metamaterial-coatings
#19
Sunil Kumar, Francis Maury, Naoufal Bahlawane
As a strongly correlated metal oxide, VO2 inspires several highly technological applications. The challenging reliable wafer-scale synthesis of high quality polycrystalline VO2 coatings is demonstrated on 4" Si taking advantage of the oxidative sintering of chemically vapor deposited VO2 films. This approach results in films with a semiconductor-metal transition (SMT) quality approaching that of the epitaxial counterpart. SMT occurs with an abrupt electrical resistivity change exceeding three orders of magnitude with a narrow hysteresis width...
November 24, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27876753/metamaterials-prime-time
#20
Andrea Alù
No abstract text is available yet for this article.
November 23, 2016: Nature Materials
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