201
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Sheng C, Liu H, Zhu S, Genov DA. Active control of electromagnetic radiation through an enhanced thermo-optic effect. Sci Rep 2015; 5:8835. [PMID: 25746689 PMCID: PMC5390077 DOI: 10.1038/srep08835] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 02/05/2015] [Indexed: 11/09/2022] Open
Abstract
The control of electromagnetic radiation in transformation optical metamaterials brings the development of vast variety of optical devices. Of a particular importance is the possibility to control the propagation of light with light. In this work, we use a structured planar cavity to enhance the thermo-optic effect in a transformation optical waveguide. In the process, a control laser produces apparent inhomogeneous refractive index change inside the waveguides. The trajectory of a second probe laser beam is then continuously tuned in the experiment. The experimental results agree well with the developed theory. The reported method can provide a new approach toward development of transformation optical devices where active all-optical control of the impinging light can be achieved.
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Affiliation(s)
- Chong Sheng
- National Laboratory of Solid State Microstructures &School of Physics, Collaborative Innovation Center of Advanced Microstructures, National Center of Microstructures and Quantum Manipulation, Nanjing University, Nanjing 210093, China
| | - Hui Liu
- National Laboratory of Solid State Microstructures &School of Physics, Collaborative Innovation Center of Advanced Microstructures, National Center of Microstructures and Quantum Manipulation, Nanjing University, Nanjing 210093, China
| | - Shining Zhu
- National Laboratory of Solid State Microstructures &School of Physics, Collaborative Innovation Center of Advanced Microstructures, National Center of Microstructures and Quantum Manipulation, Nanjing University, Nanjing 210093, China
| | - Dentcho A Genov
- Center for Applied Physics Studies, Louisiana Tech University, Ruston, Louisiana 71270, USA
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202
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Sadeghi MM, Li S, Xu L, Hou B, Chen H. Transformation optics with Fabry-Pérot resonances. Sci Rep 2015; 5:8680. [PMID: 25726924 PMCID: PMC4345524 DOI: 10.1038/srep08680] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 01/12/2015] [Indexed: 11/22/2022] Open
Abstract
Transformation optics is a powerful tool to design various novel devices, such as invisibility cloak. Fantastic effects from this technique are usually accompanied with singular mappings, resulting in challenging implementations and narrow bands of working frequencies. Here in this article, Fabry-Pérot resonances in materials of extreme anisotropy are used to design various transformation optical devices that are not only easy to realize but also work well for a set of resonant frequencies (multiple frequencies). As an example, a prototype of a cylindrical concentrator is fabricated for microwaves.
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Affiliation(s)
- M M Sadeghi
- College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, China
| | - Sucheng Li
- College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, China
| | - Lin Xu
- College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, China
| | - Bo Hou
- College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, China
| | - Huanyang Chen
- College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, China
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203
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Cheng Q, Wu K, Shi Y, Wang H, Wang GP. Directionally hiding objects and creating illusions above a carpet-like device by reflection holography. Sci Rep 2015; 5:8581. [PMID: 25716451 PMCID: PMC4341210 DOI: 10.1038/srep08581] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/27/2015] [Indexed: 12/04/2022] Open
Abstract
Realization of a perfect invisibility cloak still challenges the current fabricating technologies. Most experiments, if not all, are hence focused on carpet cloaks because of their relatively low requirements to material properties. Nevertheless, present invisibility carpets are used to hide beneath objects. Here, we report a carpet-like device to directionally conceal objects and further to create illusions above it. The device is fabricated through recording a reflection hologram of objects and is used to produce a time-reversed signal to compensate for the information of the objects and further to create light field of another object so as to realize both functions of hiding the objects and creating illusions, respectively. The carpet-like device can work for macroscopic objects at visible wavelength as the distance between objects and device is at decimeter scale. Our carpet-like device to realizing invisibility and creating illusions may provide a robust way for crucial applications of magic camouflaging and anti-detection etc.
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Affiliation(s)
- Qiluan Cheng
- School of Physics and Technology, Wuhan University, Wuhan 430072, Hubei, P. R. China
| | - Kedi Wu
- College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, Guangdong, P. R. China
| | - Yile Shi
- Institute of Information Optics, Zhejiang Normal University, Jinhua 321000, Zhejiang, P. R. China
| | - Hui Wang
- Institute of Information Optics, Zhejiang Normal University, Jinhua 321000, Zhejiang, P. R. China
| | - Guo Ping Wang
- 1] School of Physics and Technology, Wuhan University, Wuhan 430072, Hubei, P. R. China [2] College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, Guangdong, P. R. China
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204
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Zinkiewicz Ł, Haberko J, Wasylczyk P. Highly asymmetric near infrared light transmission in an all-dielectric grating-on-mirror photonic structure. OPTICS EXPRESS 2015; 23:4206-4211. [PMID: 25836458 DOI: 10.1364/oe.23.004206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We demonstrate a photonic structure, composed of a dielectric quarter-wavelength stack topped with a transmission phase grating, designed to exhibit a significant asymmetry in the near infrared light transmission for waves propagating in opposite directions. The asymmetry, defined as the difference between the intensity transmission coefficients, reaches 0.72 ± 0.06 for a single wavelength and exceeds 0.2 over a spectral range spanning from 700 to 850 nm for one incident polarization and 750-800 nm for both polarizations. The experimental results are consistent with the numerical model of light propagation in the structure.
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205
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Dupont G, Kimmoun O, Molin B, Guenneau S, Enoch S. Numerical and experimental study of an invisibility carpet in a water channel. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:023010. [PMID: 25768600 DOI: 10.1103/physreve.91.023010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Indexed: 06/04/2023]
Abstract
We propose a numerical and an experimental study of an invisibility carpet for linear water waves. In the first part, we introduce the concept of an invisibility carpet in the case of linear water waves and apply this concept for a bounded problem: a wavetank. In the second part, we study a simpler case where we attempt to render invisible a vertical dihedral at the end of a wavetank. This is done by placing a structure consisting of 18 vertical poles with trapezoidal cross-sections in front of the dihedral. For these two configurations, with and without the carpet, we focus on the far-field reflected wave consisting of an inline mode and the first sloshing (plus progressive) mode. We show that our design achieves invisibility.
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Affiliation(s)
- Guillaume Dupont
- Aix Marseille Université, CNRS, Ecole Centrale Marseille, Institut Fresnel, 13013 Marseille, France
- Aix Marseille Université, CNRS, Ecole Centrale Marseille, IRPHE, 13013 Marseille, France
| | - Olivier Kimmoun
- Aix Marseille Université, CNRS, Ecole Centrale Marseille, IRPHE, 13013 Marseille, France
| | - Bernard Molin
- Aix Marseille Université, CNRS, Ecole Centrale Marseille, IRPHE, 13013 Marseille, France
| | - Sebastien Guenneau
- Aix Marseille Université, CNRS, Ecole Centrale Marseille, Institut Fresnel, 13013 Marseille, France
| | - Stefan Enoch
- Aix Marseille Université, CNRS, Ecole Centrale Marseille, Institut Fresnel, 13013 Marseille, France
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206
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Martínez-Herrero R, Maluenda D, Juvells I, Carnicer A. Experimental implementation of tightly focused beams with unpolarized transversal component at any plane. OPTICS EXPRESS 2014; 22:32419-32428. [PMID: 25607204 DOI: 10.1364/oe.22.032419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The aim of this paper is to provide a formal framework for designing highly focused fields with specific transversal features when the incoming beam is partially polarized. More specifically, we develop a field with a transversal component that remains unpolarized in the focal area. Special attention is paid to the design of the input beam and the development of the experiment. The implementation of such fields is possible by using an interferometric setup combined with the use of digital holography techniques. Experimental results are compared with those obtained numerically.
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207
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Rodriguez SRK, Bernal Arango F, Steinbusch TP, Verschuuren MA, Koenderink AF, Gómez Rivas J. Breaking the symmetry of forward-backward light emission with localized and collective magnetoelectric resonances in arrays of pyramid-shaped aluminum nanoparticles. PHYSICAL REVIEW LETTERS 2014; 113:247401. [PMID: 25541803 DOI: 10.1103/physrevlett.113.247401] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Indexed: 06/04/2023]
Abstract
We propose aluminum nanopyramids (ANPs) as magnetoelectric optical antennas to tailor the forward versus backward luminescence spectrum. We present light extinction and emission experiments for an ANP array wherein magnetoelectric localized resonances couple to in-plane diffracted orders. This coupling leads to spectrally sharp collective resonances. Luminescent molecules drive both localized and collective resonances, and we experimentally demonstrate an unconventional forward versus backward luminescence spectrum. Through analytical calculations, we show that the magnetic, magnetoelectric, and quadrupolar moments of ANPs—which lie at the origin of the observed effects—are enhanced by their tapering and height. Full-wave simulations show that localized and delocalized magnetic surface waves, with an excitation strength depending on the plane wave direction, direct the forward versus backward emitted intensity.
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Affiliation(s)
- S R K Rodriguez
- Center for Nanophotonics, FOM Institute AMOLF, c/o Philips Research Laboratories, High Tech Campus 4, 5656 AE Eindhoven, The Netherlands
| | - F Bernal Arango
- Center for Nanophotonics, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - T P Steinbusch
- Center for Nanophotonics, FOM Institute AMOLF, c/o Philips Research Laboratories, High Tech Campus 4, 5656 AE Eindhoven, The Netherlands
| | - M A Verschuuren
- Philips Research Laboratories, High Tech Campus 4, 5656 AE Eindhoven, The Netherlands
| | - A F Koenderink
- Center for Nanophotonics, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - J Gómez Rivas
- Center for Nanophotonics, FOM Institute AMOLF, c/o Philips Research Laboratories, High Tech Campus 4, 5656 AE Eindhoven, The Netherlands and COBRA Research Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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208
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Abstract
Despite much interest and progress in optical spatial cloaking, a three-dimensional (3D), transmitting, continuously multidirectional cloak in the visible regime has not yet been demonstrated. Here we experimentally demonstrate such a cloak using ray optics, albeit with some edge effects. Our device requires no new materials, uses isotropic off-the-shelf optics, scales easily to cloak arbitrarily large objects, and is as broadband as the choice of optical material, all of which have been challenges for current cloaking schemes. In addition, we provide a concise formalism that quantifies and produces perfect optical cloaks in the small-angle ('paraxial') limit.
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209
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Ma Y, Liu Y, Raza M, Wang Y, He S. Experimental demonstration of a multiphysics cloak: manipulating heat flux and electric current simultaneously. PHYSICAL REVIEW LETTERS 2014; 113:205501. [PMID: 25432046 DOI: 10.1103/physrevlett.113.205501] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Indexed: 06/04/2023]
Abstract
Invisible cloaks have been widely explored in many different physical systems but usually for a single phenomenon for one device. In this Letter we make an experimental attempt to show a multidisciplinary framework that has the capability to simultaneously respond to two different physical excitations according to predetermined scenarios. As a proof of concept, we implement an electric-thermal bifunctional device that can guide both electric current and heat flux "across" a strong 'scatterer' (air cavity) and restore their original diffusion directions as if nothing exists along the paths, thus rendering dual cloaking effects for objects placed inside the cavity. This bifunctional cloaking performance is also numerically verified for a line-source nonuniform excitation. Our results and the fabrication technique presented here will help broaden the current research scope for multiple disciplines and may pave a way to manipulate multiple flows and create new functional devices, e.g., for on-chip applications.
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Affiliation(s)
- Yungui Ma
- State Key Lab of Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University, Hangzhou 310058, China
| | - Yichao Liu
- State Key Lab of Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University, Hangzhou 310058, China
| | - Muhammad Raza
- State Key Lab of Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University, Hangzhou 310058, China
| | - Yudong Wang
- State Key Lab of Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University, Hangzhou 310058, China
| | - Sailing He
- State Key Lab of Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, Department of Optical Engineering, Zhejiang University, Hangzhou 310058, China and Department of Electromagnetic Engineering, School of Electrical Engineering, Royal Institute of Technology, S-100 44 Stockholm, Sweden
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210
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Xu L, Chen H. Logarithm conformal mapping brings the cloaking effect. Sci Rep 2014; 4:6862. [PMID: 25359138 PMCID: PMC4215307 DOI: 10.1038/srep06862] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/03/2014] [Indexed: 11/15/2022] Open
Abstract
Over the past years, invisibility cloaks have been extensively discussed since transformation optics emerges. Generally, the electromagnetic parameters of invisibility cloaks are complicated tensors, yet difficult to realize. As a special method of transformation optics, conformal mapping helps us design invisibility cloak with isotropic materials of a refractive index distribution. However, for all proposed isotropic cloaks, the refractive index range is at such a breadth that challenges current experimental fabrication. In this work, we propose two new kinds of logarithm conformal mappings for invisible device designs. For one of the mappings, the refractive index distribution of conformal cloak varies from 0 to 9.839, which is more feasible for future implementation. Numerical simulations by using finite element method are performed to confirm the theoretical analysis.
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Affiliation(s)
- Lin Xu
- College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, the People's Republic of China
| | - Huanyang Chen
- College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, the People's Republic of China
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211
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Martínez-Herrero R, Juvells I, Carnicer A. Design of highly focused fields that remain unpolarized on axis. OPTICS LETTERS 2014; 39:6025-6028. [PMID: 25361146 DOI: 10.1364/ol.39.006025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Research on the properties of highly focused fields mainly involved fully polarized light, whereas partially polarized waves received less attention. The aim of this Letter is to provide an appropriate framework, for designing some features of the focused field, when dealing with incoming partially polarized beams. In particular, in this Letter, we describe how to get an unpolarized field on the axis of a high numerical aperture objective lens. Some numerical results that corroborate theoretical predictions are provided.
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212
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George D, Lutkenhaus J, Lowell D, Moazzezi M, Adewole M, Philipose U, Zhang H, Poole ZL, Chen KP, Lin Y. Holographic fabrication of 3D photonic crystals through interference of multi-beams with 4 + 1, 5 + 1 and 6 + 1 configurations. OPTICS EXPRESS 2014; 22:22421-22431. [PMID: 25321713 DOI: 10.1364/oe.22.022421] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this paper, we are able to fabricate 3D photonic crystals or quasi-crystals through single beam and single optical element based holographic lithography. The reflective optical elements are used to generate multiple side beams with s-polarization and one central beam with circular polarization which in turn are used for interference based holographic lithography without the need of any other bulk optics. These optical elements have been used to fabricate 3D photonic crystals with 4, 5 or 6-fold symmetry. A good agreement has been observed between fabricated holographic structures and simulated interference patterns.
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213
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Ma HF, Wang GZ, Jiang WX, Cui TJ. Independent control of differently-polarized waves using anisotropic gradient-index metamaterials. Sci Rep 2014; 4:6337. [PMID: 25231412 PMCID: PMC4166714 DOI: 10.1038/srep06337] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 08/20/2014] [Indexed: 11/13/2022] Open
Abstract
We propose a kind of anisotropic gradient-index (GRIN) metamaterials, which can be used to control differently-polarized waves independently. We show that two three- dimensional (3D) planar lenses made of such anisotropic GRIN metamaterials are able to make arbitrary beam deflections for the vertical (or horizontal) polarization but have no response to the horizontal (or vertical) polarization. Then the vertically- and horizontally-polarized waves are separated and controlled independently to deflect to arbitrarily different directions by designing the anisotropic GRIN planar lenses. We make experimental verifications of the lenses using such a special metamaterial, which has both electric and magnetic responses simultaneously to reach approximately equal permittivity and permeability. Hence excellent impedance matching is obtained between the GRIN planar lenses and the air. The measurement results demonstrate good performance on the independent controls of differently-polarized waves, as observed in the numerical simulations.
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Affiliation(s)
- Hui Feng Ma
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096, China
| | - Gui Zhen Wang
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096, China
| | - Wei Xiang Jiang
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096, China
| | - Tie Jun Cui
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing 210096, China
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214
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Krauter CM, Schirmer J, Jacob CR, Pernpointner M, Dreuw A. Plasmons in molecules: Microscopic characterization based on orbital transitions and momentum conservation. J Chem Phys 2014; 141:104101. [DOI: 10.1063/1.4894266] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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215
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Liu S, Zhang HC, Xu HX, Cui TJ. Nonideal ultrathin mantle cloak for electrically large conducting cylinders. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:2075-2082. [PMID: 25401449 DOI: 10.1364/josaa.31.002075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Based on the concept of the scattering cancellation technique, we propose a nonideal ultrathin mantle cloak that can efficiently suppress the total scattering cross sections of an electrically large conducting cylinder (over one free-space wavelength). The cloaking mechanism is investigated in depth based on the Mie scattering theory and is simultaneously interpreted from the perspective of far-field bistatic scattering and near-field distributions. We remark that, unlike the perfect transformation-optics-based cloak, this nonideal cloaking technique is mainly designed to minimize simultaneously several scattering multipoles of a relatively large geometry around considerably broad bandwidth. Numerical simulations and experimental results show that the antiscattering ability of the metasurface gives rise to excellent total scattering reduction of the electrically large cylinder and remarkable electric-field restoration around the cloak. The outstanding cloaking performance together with the good features of and ultralow profile, flexibility, and easy fabrication predict promising applications in the microwave frequencies.
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216
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Kort-Kamp WJM, Rosa FSS, Pinheiro FA, Farina C. Molding the flow of light with a magnetic field: plasmonic cloaking and directional scattering. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:1969-1976. [PMID: 25401436 DOI: 10.1364/josaa.31.001969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We investigate electromagnetic (EM) scattering and plasmonic cloaking in a system composed of a dielectric cylinder coated with a magneto-optical shell. In the long-wavelength limit we demonstrate that the application of an external magnetic field can not only switch on and off the cloaking mechanism but also mitigate losses, as the absorption cross section is shown to drop sharply precisely at the cloaking operation frequency band. We also show that the angular distribution of the scattered radiation can be effectively controlled by applying an external magnetic field, allowing for a swift change in the scattering pattern. By demonstrating that these results are feasible with realistic, existing magneto-optical materials, such as graphene epitaxially grown on SiC, we suggest that magnetic fields could be used as effective, versatile external agents to tune plasmonic cloaks and to dynamically control EM scattering in an unprecedented way. We hope that these results may find use in disruptive photonic technologies.
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217
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Ushiba S, Shoji S, Masui K, Kono J, Kawata S. Direct laser writing of 3D architectures of aligned carbon nanotubes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:5653-5657. [PMID: 24944112 DOI: 10.1002/adma.201400783] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 05/01/2014] [Indexed: 06/03/2023]
Abstract
Direct laser writing through two-photon polymerization lithography is used to fabricate 3D nanostructures containing aligned single-wall carbon nanotubes (SWCNTs). SWCNTs are aligned in the laser scanning directions while they are embedded in the structure. The alignment is induced by spatial confinement, volume shrinkage, and the optical gradient force. This method is expected to lead to new applications based on aligned SWCNTs.
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Affiliation(s)
- Shota Ushiba
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
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218
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Tsargorodska A, El Zubir O, Darroch B, Cartron ML, Basova T, Hunter CN, Nabok AV, Leggett GJ. Fast, simple, combinatorial routes to the fabrication of reusable, plasmonically active gold nanostructures by interferometric lithography of self-assembled monolayers. ACS NANO 2014; 8:7858-7869. [PMID: 25007208 DOI: 10.1021/nn5014319] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We describe a fast, simple method for the fabrication of reusable, robust gold nanostructures over macroscopic (cm(2)) areas. A wide range of nanostructure morphologies is accessible in a combinatorial fashion. Self-assembled monolayers of alkylthiolates on chromium-primed polycrystalline gold films are patterned using a Lloyd's mirror interferometer and etched using mercaptoethylamine in ethanol in a rapid process that does not require access to clean-room facilities. The use of a Cr adhesion layer facilitates the cleaning of specimens by immersion in piranha solution, enabling their repeated reuse without significant change in their absorbance spectra over two years. A library of 200 different nanostructures was prepared and found to exhibit a range of optical behavior. Annealing yielded structures with a uniformly high degree of crystallinity that exhibited strong plasmon bands. Using a combinatorial approach, correlations were established between the preannealing morphologies (determined by the fabrication conditions) and the postannealing optical properties that enabled specimens to be prepared "to order" with a selected localized surface plasmon resonance. The refractive index sensitivity of gold nanostructures formed in this way was found to correlate closely with measurements reported for structures fabricated by other methods. Strong enhancements were observed in the Raman spectra of tetra-tert-butyl-substituted phthalocyanine. The shift in the position of the plasmon band after site-specific attachment of histidine-tagged green fluorescent protein (His-GFP) and bacteriochlorophyll a was measured for a range of nanostructured films, enabling the rapid identification of the one that yielded the largest shift. This approach offers a simple route to the production of durable, reusable, macroscopic arrays of gold nanostructures with precisely controllable morphologies.
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Affiliation(s)
- Anna Tsargorodska
- Department of Chemistry, University of Sheffield , Brook Hill, Sheffield S3 7HF, U.K
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219
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Smalley JST, Vallini F, Kanté B, Fainman Y. Modal amplification in active waveguides with hyperbolic dispersion at telecommunication frequencies. OPTICS EXPRESS 2014; 22:21088-21105. [PMID: 25321309 DOI: 10.1364/oe.22.021088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a method for studying amplification of electromagnetic modes in active, circularly symmetric waveguides with hyperbolic dispersion. Using this method, we obtain a closed-form expression for the modal threshold condition. We find that modal amplification is possible in a region of the radius-wavelength phase-space with small enough radius so that propagation of the mode is permitted while modal energy and phase counter-propagate. At telecommunication frequencies, such a situation is achievable only when the absolute value of the real metal permittivity exceeds that of the active dielectric. We validate our theoretical conclusions with numerical simulations that explain the threshold condition in terms of an energy balance between the longitudinal and radial components of the electric field.
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220
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Oner BB, Can MG, Kurt H. Dual polarized broadband and all dielectric partial cloaking using stacked graded index structures. OPTICS EXPRESS 2014; 22:20457-20462. [PMID: 25321252 DOI: 10.1364/oe.22.020457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We propose broadband one-dimensional optical cloaking design based on isotropic and purely dielectric non-absorbent materials. The photonic structures are formed by utilizing graded index (GRIN) concept in stacked form. All simulations are performed by finite-difference time-domain and plane wave basis frequency domain numerical methods. Indications in ray optics are also presented for the cloaking device. The refractive index distribution of the design is also obtained via effective medium theory. The cloaking devices can reroute wavelengths of light in one dimension. The rerouted light is avoided to reach the interior region of the stacked GRIN structure. Unidirectional GRIN cloaking structure demonstrates low-loss and large bandwidth characteristics. It is shown that the structure operates in dual polarization mode. Performed numerical analyses reveal the capability of cloaking devices to hide arbitrary shaped large objects from the incident light.
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221
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Bony PY, Guasoni M, Morin P, Sugny D, Picozzi A, Jauslin HR, Pitois S, Fatome J. Temporal spying and concealing process in fibre-optic data transmission systems through polarization bypass. Nat Commun 2014; 5:4678. [PMID: 25135759 PMCID: PMC4143945 DOI: 10.1038/ncomms5678] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 07/11/2014] [Indexed: 11/10/2022] Open
Abstract
Recent research has been focused on the ability to manipulate a light beam in such a way to hide, namely to cloak, an event over a finite time or localization in space. The main idea is to create a hole or a gap in the spatial or time domain so as to allow for an object or data to be kept hidden for a while and then to be restored. By enlarging the field of applications of this concept to telecommunications, researchers have recently reported the possibility to hide transmitted data in an optical fibre. Here we report the first experimental demonstration of perpetual temporal spying and blinding process of optical data in fibre-optic transmission line based on polarization bypass. We successfully characterize the performance of our system by alternatively copying and then concealing 100% of a 10-Gb s−1 transmitted signal. Recent temporal cloaking schemes hid or revealed temporal events and data using spectral modifications in a continuous wave probe. Here, Bony et al. propose using reversible manipulation of the polarization state of transmitted data to perpetually copy or conceal data in a fibre-optic transmission system.
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Affiliation(s)
- P Y Bony
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Avenue Alain Savary, 21078 Dijon, France
| | - M Guasoni
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Avenue Alain Savary, 21078 Dijon, France
| | - P Morin
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Avenue Alain Savary, 21078 Dijon, France
| | - D Sugny
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Avenue Alain Savary, 21078 Dijon, France
| | - A Picozzi
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Avenue Alain Savary, 21078 Dijon, France
| | - H R Jauslin
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Avenue Alain Savary, 21078 Dijon, France
| | - S Pitois
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Avenue Alain Savary, 21078 Dijon, France
| | - J Fatome
- Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), UMR 6303 CNRS-Université de Bourgogne, 9 Avenue Alain Savary, 21078 Dijon, France
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222
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Butun S, Aydin K. Structurally tunable resonant absorption bands in ultrathin broadband plasmonic absorbers. OPTICS EXPRESS 2014; 22:19457-19468. [PMID: 25321029 DOI: 10.1364/oe.22.019457] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Light absorption is a fundamental optical process playing significantly important role in wide variety of applications ranging from photovoltaics to photothermal therapy. Semiconductors have well-defined absorption bands with low-energy edge dictated by the band gap energy, therefore it is rather challenging to tune the absorption bandwidth of semiconductors. However, resonant absorbers based on plasmonic nanostructures and optical metamaterials emerged as alternative light absorbers due to spectrally selective absorption bands resulting from optical resonances. Recently, a broadband plasmonic absorber design was introduced by Aydin et al. with a reasonably high broadband absorption. Based on that design, here, structurally tunable, broadband absorbers with improved performance are demonstrated. This broadband absorber has a total thickness of 190 nm with 80% average measured absorption (90% simulated absorption) over the entire visible spectrum (400 - 700 nm). Moreover, the effect of the metal and the oxide thicknesses on the absorption spectra are investigated and results indicate that the shorter and the longer band-edge of broadband absorption can be structurally tuned with the metal and the oxide thicknesses, as well as with the resonator size. Detailed numerical simulations shed light on the type of optical resonances that contribute to the broadband absorption response and provide a design guideline for realizing plasmonic absorbers with structurally tunable bandwidths.
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223
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Liu L, Zhang X, Kenney M, Su X, Xu N, Ouyang C, Shi Y, Han J, Zhang W, Zhang S. Broadband metasurfaces with simultaneous control of phase and amplitude. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:5031-6. [PMID: 24863731 DOI: 10.1002/adma.201401484] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 04/30/2014] [Indexed: 05/17/2023]
Abstract
By combining the freedom of both the structural design and the orientation of split ring resonator antennas, we demonstrate terahertz metasurfaces that are capable of controlling both the phase and amplitude profiles over a very broad bandwidth. As an example, we show that the phase-amplitude metasurfaces can be engineered to control the diffraction orders arbitrarily.
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Affiliation(s)
- Lixiang Liu
- School of Physics & Astronomy, University of Birmingham, Birmingham, B15 2TT, UK; Institute of Solid State Physics, Shanxi Datong University, Datong, 037009, China
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224
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Wang K, Zhao J, Cheng Q, Dong DS, Cui TJ. Broadband and broad-angle low-scattering metasurface based on hybrid optimization algorithm. Sci Rep 2014; 4:5935. [PMID: 25089367 PMCID: PMC4120860 DOI: 10.1038/srep05935] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 07/15/2014] [Indexed: 11/30/2022] Open
Abstract
A broadband and broad-angle low-scattering metasurface is designed, fabricated, and characterized. Based on the optimization algorithm and far-field scattering pattern analysis, we propose a rapid and efficient method to design metasurfaces, which avoids the large amount of time-consuming electromagnetic simulations. Full-wave simulation and measurement results show that the proposed metasurface is insensitive to the polarization of incident waves, and presents good scattering-reduction properties for oblique incident waves.
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Affiliation(s)
- Ke Wang
- State Key Laboratory of Millimeter Waves, Department of Radio Engineering Southeast University, Nanjing 210096, P. R. China
| | - Jie Zhao
- State Key Laboratory of Millimeter Waves, Department of Radio Engineering Southeast University, Nanjing 210096, P. R. China
| | - Qiang Cheng
- State Key Laboratory of Millimeter Waves, Department of Radio Engineering Southeast University, Nanjing 210096, P. R. China
| | - Di Sha Dong
- State Key Laboratory of Millimeter Waves, Department of Radio Engineering Southeast University, Nanjing 210096, P. R. China
| | - Tie Jun Cui
- State Key Laboratory of Millimeter Waves, Department of Radio Engineering Southeast University, Nanjing 210096, P. R. China
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225
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Schittny R, Kadic M, Bückmann T, Wegener M. Invisibility cloaking in a diffusive light scattering medium. Science 2014; 345:427-9. [DOI: 10.1126/science.1254524] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Robert Schittny
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), D-76128 Karlsruhe, Germany
- Deutsche Forschungsgemeinschaft (DFG)–Center for Functional Nanostructures (CFN), KIT, D-76128 Karlsruhe, Germany
| | - Muamer Kadic
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), D-76128 Karlsruhe, Germany
- Institute of Nanotechnology, KIT, D-76021 Karlsruhe, Germany
| | - Tiemo Bückmann
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), D-76128 Karlsruhe, Germany
- Deutsche Forschungsgemeinschaft (DFG)–Center for Functional Nanostructures (CFN), KIT, D-76128 Karlsruhe, Germany
| | - Martin Wegener
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), D-76128 Karlsruhe, Germany
- Deutsche Forschungsgemeinschaft (DFG)–Center for Functional Nanostructures (CFN), KIT, D-76128 Karlsruhe, Germany
- Institute of Nanotechnology, KIT, D-76021 Karlsruhe, Germany
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226
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Liu Y, Jiang W, He S, Ma Y. An efficient plate heater with uniform surface temperature engineered with effective thermal materials. OPTICS EXPRESS 2014; 22:17006-17015. [PMID: 25090515 DOI: 10.1364/oe.22.017006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Extended from its electromagnetic counterpart, transformation thermodynamics applied to thermal conduction equations can map a virtual geometry into a physical thermal medium, realizing the manipulation of heat flux with almost arbitrarily desired diffusion paths, which provides unprecedented opportunities to create thermal devices unconceivable or deemed impossible before. In this work we employ this technique to design an efficient plate heater that can transiently achieve a large surface of uniform temperature powered by a small thermal source. As opposed to the traditional approach of relying on the deployment of a resistor network, our approach fully takes advantage of an advanced functional material system to guide the heat flux to achieve the desired temperature heating profile. A different set of material parameters for the transformed device has been developed, offering the parametric freedom for practical applications. As a proof of concept, the proposed devices are implemented with engineered thermal materials and show desired heating behaviors consistent with numerical simulations. Unique applications for these devices can be envisioned where stringent temperature uniformity and a compact heat source are both demanded.
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227
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Sun TQ, Ye Q, Wang XW, Wang J, Deng ZC, Mei JC, Zhou WY, Zhang CP, Tian JG. Scanning focused refractive-index microscopy. Sci Rep 2014; 4:5647. [PMID: 25008374 PMCID: PMC4090626 DOI: 10.1038/srep05647] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 06/23/2014] [Indexed: 11/09/2022] Open
Abstract
We present a novel scanning focused refractive-index microscopy (SFRIM) technique to obtain the refractive index (RI) profiles of objects. The method uses a focused laser as the light source, and combines the derivative total reflection method (DTRM), projection magnification, and scanning technique together. SFRIM is able to determine RIs with an accuracy of 0.002, and the central spatial resolution achieved is 1 µm, which is smaller than the size of the focal spot. The results of measurements carried out on cedar oil and a gradient-refractive-index (GRIN) lens agree well with theoretical expectations, verifying the accuracy of SFRIM. Furthermore, using SFRIM, to the best of our knowledge we have extracted for the first time the RI profile of a periodically modulated photosensitive gelatin sample. SFRIM is the first RI profile-resolved reflected light microscopy technique that can be applied to scattering and absorbing samples. SFRIM enables the possibility of performing RI profile measurements in a variety of applications, including optical waveguides, photosensitive materials and devices, photorefractive effect studies, and RI imaging in biomedical fields.
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Affiliation(s)
- Teng-Qian Sun
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Qing Ye
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Xiao-Wan Wang
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Jin Wang
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Zhi-Chao Deng
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Jian-Chun Mei
- Advanced Technology Institute, Nankai University, Tianjin 300071, China
| | - Wen-Yuan Zhou
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Chun-Ping Zhang
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
| | - Jian-Guo Tian
- Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of physics and TEDA Applied Physics School, Nankai University, Tianjin 300071, China
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228
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Han T, Wu Z. Electromagnetic wave rotators with homogeneous, nonmagnetic, and isotropic materials. OPTICS LETTERS 2014; 39:3698-3701. [PMID: 24978714 DOI: 10.1364/ol.39.003698] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We propose a novel optical transformation to design an arbitrary N-sided regular polygonal rotator, which demonstrates that the inhomogeneity of a rotator can be completely removed, and only anisotropy is needed to rotate wavefronts without any perturbance. An N-sided regular polygonal rotator will give rise to a rotation angle of 360°/N, thereby leading to a series of discrete rotation angles with different choices of N. Practical realization of such homogeneous rotators is suggested by using only four kinds of nonmagnetic isotropic dielectrics throughout. The dielectrics can be easily arranged in a planarly stratified configuration due to all the flat boundaries, which makes the rotator much easier in fabrication and application. Full-wave simulation validates the proposed scheme applicable to both passive object and active source with excellent performance.
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229
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Bückmann T, Thiel M, Kadic M, Schittny R, Wegener M. An elasto-mechanical unfeelability cloak made of pentamode metamaterials. Nat Commun 2014; 5:4130. [DOI: 10.1038/ncomms5130] [Citation(s) in RCA: 356] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 05/16/2014] [Indexed: 11/09/2022] Open
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230
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Ray-optics cloaking devices for large objects in incoherent natural light. Nat Commun 2014; 4:2652. [PMID: 24153410 PMCID: PMC3826629 DOI: 10.1038/ncomms3652] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 09/20/2013] [Indexed: 11/16/2022] Open
Abstract
A cloak that can hide living creatures from sight is a common feature of mythology but still remains unrealized as a practical device. To preserve the wave phase, the previous cloaking solution proposed by Pendry and colleagues required transformation of the electromagnetic space around the hidden object in such a way that the rays bending around the object inside the cloak region have to travel faster than those passing it by. This difficult phase preservation requirement is the main obstacle for building a broadband polarization-insensitive cloak for large objects. Here we propose a simplified version of Pendry’s cloak by abolishing the requirement for phase preservation, as it is irrelevant for observation using incoherent natural light with human eyes, which are phase and polarization insensitive. This allows for a cloak design on large scales using commonly available materials. We successfully demonstrate the cloaking of living creatures, a cat and a fish, from the eye. Although many electromagnetic cloaking schemes exist at different wavelengths, realizing a broadband visible wavelength device is hard. By relaxing the need for phase preservation inherent to most methods, Chen et al. present a ray-optics scheme for cloaking large-scale objects from the human eye.
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231
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Ha K, Choi H, Jung K, Han K, Lee JK, Ahn K, Choi M. Large-area assembly of three-dimensional nanoparticle structures via ion assisted aerosol lithography with a multi-pin spark discharge generator. NANOTECHNOLOGY 2014; 25:225302. [PMID: 24833290 DOI: 10.1088/0957-4484/25/22/225302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present an approach utilizing ion assisted aerosol lithography (IAAL) with a newly designed multi-pin spark discharge generator (SDG) for fabricating large-area three-dimensional (3D) nanoparticle-structure (NPS) arrays. The design of the multi-pin SDG allows us to uniformly construct 3D NPSs on a large area of 50 mm × 50 mm in a parallel fashion at atmospheric pressure. The ion-induced focusing capability of IAAL significantly reduces the feature size of 3D NPSs compared to that of the original pre-patterns formed on a substrate. The spatial uniformity of 3D NPSs is above 95% using the present multi-pin SDG, which is far superior to that of the previous single-pin SDG with less than 32% uniformity. The effect of size distributions of nanoparticles generated via the multi-pin SDG on the 3D NPSs also has been studied. In addition, we measured spectral reflectance for the present 3D NPSs coated with Ag, demonstrating enhanced diffuse reflectance.
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232
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Liu S, Xu HX, Zhang HC, Cui TJ. Tunable ultrathin mantle cloak via varactor-diode-loaded metasurface. OPTICS EXPRESS 2014; 22:13403-17. [PMID: 24921534 DOI: 10.1364/oe.22.013403] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We propose a tunable strategy for the ultrathin mantle cloak via metasurface. The tunable cloak is implemented by loading varactor diodes between two neighboring horizontal metallic strips which constitute the metasurface. We demonstrate that the varactor diodes enable the capacitive reactance of the metasurface to be tunable from -157 Ω to -3 Ω when the DC bias voltage is properly changed. The active metasurface is then explored to cloak conformally a conducting cylinder. Both numerical and experiment results show that the cloaking frequency can be continuously controlled from 2.3 GHz to 3.7 GHz by appropriately adjusting the bias voltage. The flexible tunability and good cloaking performance are further examined by the measured field distributions. The advanced features of tunability, low profile, and conformal ability of the ultrathin cloak pave the way for practical applications of cloaking devices.
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233
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Farhat M, Chen PY, Bağcı H, Enoch S, Guenneau S, Alù A. Platonic scattering cancellation for bending waves in a thin plate. Sci Rep 2014; 4:4644. [PMID: 24844801 PMCID: PMC4027886 DOI: 10.1038/srep04644] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 03/24/2014] [Indexed: 11/09/2022] Open
Abstract
We propose an ultra-thin elastic cloak to control the scattering of bending waves in isotropic heterogeneous thin plates. The cloak design makes use of the scattering cancellation technique applied, for the first time, to the biharmonic operator describing the propagation of bending waves in thin plates. We first analyze scattering from hard and soft cylindrical objects in the quasistatic limit, then we prove that the scattering of bending waves from an object in the near and far-field regions can be suppressed significantly by covering it with a suitably designed coating. Beyond camouflaging, these findings may have potential applications in protection of buildings from earthquakes and isolating structures from vibrations in the motor vehicle industry.
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Affiliation(s)
- M. Farhat
- Division of Computer, Electrical, and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - P.-Y. Chen
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - H. Bağcı
- Division of Computer, Electrical, and Mathematical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - S. Enoch
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel, UMR 7249, 13013 Marseille, France
| | - S. Guenneau
- Aix-Marseille Université, CNRS, Centrale Marseille, Institut Fresnel, UMR 7249, 13013 Marseille, France
| | - A. Alù
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
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234
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Zigoneanu L, Popa BI, Cummer SA. Three-dimensional broadband omnidirectional acoustic ground cloak. NATURE MATERIALS 2014; 13:352-5. [PMID: 24608143 DOI: 10.1038/nmat3901] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 01/31/2014] [Indexed: 05/24/2023]
Abstract
The control of sound propagation and reflection has always been the goal of engineers involved in the design of acoustic systems. A recent design approach based on coordinate transformations, which is applicable to many physical systems, together with the development of a new class of engineered materials called metamaterials, has opened the road to the unconstrained control of sound. However, the ideal material parameters prescribed by this methodology are complex and challenging to obtain experimentally, even using metamaterial design approaches. Not surprisingly, experimental demonstration of devices obtained using transformation acoustics is difficult, and has been implemented only in two-dimensional configurations. Here, we demonstrate the design and experimental characterization of an almost perfect three-dimensional, broadband, and, most importantly, omnidirectional acoustic device that renders a region of space three wavelengths in diameter invisible to sound.
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235
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Han T, Bai X, Thong JTL, Li B, Qiu CW. Full control and manipulation of heat signatures: cloaking, camouflage and thermal metamaterials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:1731-4. [PMID: 24497430 DOI: 10.1002/adma.201304448] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 10/26/2013] [Indexed: 05/14/2023]
Abstract
Thermal camouflage and cloaking can transform an actual heat signature into a pre-controlled one. A viable recipe for controlling and manipulating heat signatures using thermal metamaterials to empower cloaking and camouflage in heat conduction is demonstrated. The thermal signature of the object is thus metamorphosed and perceived as multiple targets with different geometries and compositions, with the original object cloaked.
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Affiliation(s)
- Tiancheng Han
- Department of Electrical and Computer Engineering, National University of Singapore, 117583, Republic of Singapore
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236
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A versatile smart transformation optics device with auxetic elasto-electromagnetic metamaterials. Sci Rep 2014; 4:4084. [PMID: 24522287 PMCID: PMC3923231 DOI: 10.1038/srep04084] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 01/27/2014] [Indexed: 11/18/2022] Open
Abstract
Synergistic integration of electromagnetic (EM) and mechanical properties of metamaterials, a concept known as smart metamaterials, promises new applications across the spectrum, from flexible waveguides to shape-conforming cloaks. These applications became possible thanks to smart transformation optics (STO), a design methodology that utilizes coordinate transformations to control both EM wave propagation and mechanical deformation of the device. Here, we demonstrate several STO devices based on extremely auxetic (Poisson ratio −1) elasto-electromagnetic metamaterials, both of which exhibit enormous flexibility and sustain efficient operation upon a wide range of deformations. Spatial maps of microwave electric fields across these devices confirm our ability to deform carpet cloaks, bent waveguides, and potentially other quasi-conformal TO-based devices operating at 7 ~ 8 GHz. These devices are each fabricated from a single sheet of initially uniform (double-periodic) square-lattice metamaterial, which acquires the necessary distribution of effective permittivity entirely from the mechanical deformation of its boundary. By integrating transformation optics and continuum mechanics theory, we provide analytical derivations for the design of STO devices. Additionally, we clarify an important point relating to two-dimensional STO devices: the difference between plane stress and plane strain assumptions, which lead to elastic metamaterials with Poisson ratio −1 and −∞, respectively.
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237
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Sun J, Zeng J, Wang X, Cartwright AN, Litchinitser NM. Concealing with structured light. Sci Rep 2014; 4:4093. [PMID: 24522638 PMCID: PMC3923230 DOI: 10.1038/srep04093] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 01/30/2014] [Indexed: 11/09/2022] Open
Abstract
While making objects less visible (or invisible) to a human eye or a radar has captured people's imagination for centuries, current attempts towards realization of this long-awaited functionality range from various stealth technologies to recently proposed cloaking devices. A majority of proposed approaches share a number of common deficiencies such as design complexity, polarization effects, bandwidth, losses and the physical size or shape requirement complicating their implementation especially at optical frequencies. Here we demonstrate an alternative way to conceal macroscopic objects by structuring light itself. In our approach, the incident light is transformed into an optical vortex with a dark core that can be used to conceal macroscopic objects. Once such a beam passed around the object it is transformed back into its initial Gaussian shape with minimum amplitude and phase distortions. Therefore, we propose to use that dark core of the vortex beam to conceal an object that is macroscopic yet small enough to fit the dark (negligibly low intensity) region of the beam. The proposed concealing approach is polarization independent, easy to fabricate, lossless, operates at wavelengths ranging from 560 to 700 nm, and can be used to hide macroscopic objects providing they are smaller than vortex core.
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Affiliation(s)
- Jingbo Sun
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Jinwei Zeng
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Xi Wang
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Alexander N Cartwright
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
| | - Natalia M Litchinitser
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA
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238
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Han T, Bai X, Gao D, Thong JTL, Li B, Qiu CW. Experimental demonstration of a bilayer thermal cloak. PHYSICAL REVIEW LETTERS 2014; 112:054302. [PMID: 24580600 DOI: 10.1103/physrevlett.112.054302] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Indexed: 06/03/2023]
Abstract
Invisibility has attracted intensive research in various communities, e.g., optics, electromagnetics, acoustics, thermodynamics, dc, etc. However, many experimental demonstrations have only been achieved by virtue of simplified approaches due to the inhomogeneous and extreme parameters imposed by the transformation-optic method, and usually require a challenging realization with metamaterials. In this Letter, we demonstrate a bilayer thermal cloak made of bulk isotropic materials, and it has been validated as an exact cloak. We experimentally verified its ability to maintain the heat front and its heat protection capabilities in a 2D proof-of-concept experiment. The robustness of this scheme is validated in both 2D (including oblique heat front incidence) and 3D configurations. The proposed scheme may open a new avenue to control the diffusive heat flow in ways inconceivable with phonons, and also inspire new alternatives to the functionalities promised by transformation optics.
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Affiliation(s)
- Tiancheng Han
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Republic of Singapore
| | - Xue Bai
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Republic of Singapore and Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117546, Republic of Singapore and NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore,Kent Ridge 119620, Republic of Singapore
| | - Dongliang Gao
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Republic of Singapore
| | - John T L Thong
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Republic of Singapore and NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore,Kent Ridge 119620, Republic of Singapore
| | - Baowen Li
- Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117546, Republic of Singapore and NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore,Kent Ridge 119620, Republic of Singapore and Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering, Tongji University, 200092 Shanghai, China
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Republic of Singapore and NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore,Kent Ridge 119620, Republic of Singapore
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239
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Xu H, Shi X, Gao F, Sun H, Zhang B. Ultrathin three-dimensional thermal cloak. PHYSICAL REVIEW LETTERS 2014; 112:054301. [PMID: 24580599 DOI: 10.1103/physrevlett.112.054301] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Indexed: 05/27/2023]
Abstract
We report the first experimental realization of a three-dimensional thermal cloak shielding an air bubble in a bulk metal without disturbing the external conductive thermal flux. The cloak is made of a thin layer of homogeneous and isotropic material with specially designed three-dimensional manufacturing. The cloak's thickness is 100 μm while the cloaked air bubble has a diameter of 1 cm, achieving the ratio between dimensions of the cloak and the cloaked object 2 orders smaller than previous thermal cloaks, which were mainly realized in a two-dimensional geometry. This work can find applications in novel thermal devices in the three-dimensional physical space.
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Affiliation(s)
- Hongyi Xu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Xihang Shi
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Fei Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Handong Sun
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore and Centre for Disruptive Photonic Technologies, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Baile Zhang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore and Centre for Disruptive Photonic Technologies, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
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240
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Zhang D, Zhu M, Zhu L, Xu Q, Chen J. Controlling the polarization orientation of highly confined and enhanced surface plasmon polaritons. RSC Adv 2014. [DOI: 10.1039/c4ra11699b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We show the manipulation of the overall polarization orientation of the enhanced and confined surface plasmon polaritons near the nanostructure.
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Affiliation(s)
- Dawei Zhang
- Engineering Research Center of Optical Instrument and System
- Ministry of Education
- Shanghai Key Lab of Modern Optical System
- School of Optical-Electrical and Computer Engineering
- University of Shanghai for Science and Technology
| | - Mengjun Zhu
- Engineering Research Center of Optical Instrument and System
- Ministry of Education
- Shanghai Key Lab of Modern Optical System
- School of Optical-Electrical and Computer Engineering
- University of Shanghai for Science and Technology
| | - Linwei Zhu
- School of Physics and Optical-Electrical Engineering
- Ludong University
- Yantai 264025, China
| | - Qinfeng Xu
- School of Physics
- Nanjing University
- Nanjing, China
| | - Jiannong Chen
- School of Physics and Optical-Electrical Engineering
- Ludong University
- Yantai 264025, China
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241
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Chen PY, Argyropoulos C, Alù A. Broadening the cloaking bandwidth with non-Foster metasurfaces. PHYSICAL REVIEW LETTERS 2013; 111:233001. [PMID: 24476265 DOI: 10.1103/physrevlett.111.233001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Indexed: 06/03/2023]
Abstract
We introduce the concept and practical design of broadband, ultrathin cloaks based on non-Foster, negatively capacitive metasurfaces. By using properly tailored, active frequency-selective screens conformal to an object, within the realm of a practical realization, we show that it is possible to drastically reduce the scattering over a wide frequency range in the microwave regime, orders of magnitude broader than any available passive cloaking technology. The proposed active cloak may impact not only invisibility and camouflaging, but also practical antenna and sensing applications.
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Affiliation(s)
- Pai-Yen Chen
- The University of Texas at Austin, Department of Electrical and Computer Engineering, Austin, Texas 78712, USA
| | - Christos Argyropoulos
- The University of Texas at Austin, Department of Electrical and Computer Engineering, Austin, Texas 78712, USA
| | - Andrea Alù
- The University of Texas at Austin, Department of Electrical and Computer Engineering, Austin, Texas 78712, USA
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242
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Kadic M, Bückmann T, Schittny R, Wegener M. Metamaterials beyond electromagnetism. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2013; 76:126501. [PMID: 24190877 DOI: 10.1088/0034-4885/76/12/126501] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Metamaterials are rationally designed man-made structures composed of functional building blocks that are densely packed into an effective (crystalline) material. While metamaterials are mostly associated with negative refractive indices and invisibility cloaking in electromagnetism or optics, the deceptively simple metamaterial concept also applies to rather different areas such as thermodynamics, classical mechanics (including elastostatics, acoustics, fluid dynamics and elastodynamics), and, in principle, also to quantum mechanics. We review the basic concepts, analogies and differences to electromagnetism, and give an overview on the current state of the art regarding theory and experiment-all from the viewpoint of an experimentalist. This review includes homogeneous metamaterials as well as intentionally inhomogeneous metamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics. Examples are laminates, transient thermal cloaks, thermal concentrators and inverters, 'space-coiling' metamaterials, anisotropic acoustic metamaterials, acoustic free-space and carpet cloaks, cloaks for gravitational surface waves, auxetic mechanical metamaterials, pentamode metamaterials ('meta-liquids'), mechanical metamaterials with negative dynamic mass density, negative dynamic bulk modulus, or negative phase velocity, seismic metamaterials, cloaks for flexural waves in thin plates and three-dimensional elastostatic cloaks.
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Affiliation(s)
- Muamer Kadic
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76128 Karlsruhe, Germany
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243
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Zeng L, Song R. Controlling chloride ions diffusion in concrete. Sci Rep 2013; 3:3359. [PMID: 24285220 PMCID: PMC3842543 DOI: 10.1038/srep03359] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 11/11/2013] [Indexed: 11/17/2022] Open
Abstract
The corrosion of steel in concrete is mainly due to the chemical reaction between the chloride ions and iron ions. Indeed, this is a serious threaten for reinforced concrete structure, especially for the reinforced concrete structure in the sea. So it is urgent and important to protect concrete against chloride ions corrosion. In this work, we report multilayer concrete can cloak chloride ions. We formulated five kinds of concrete A, B, C, D and E, which are made of different proportion of cement, sand and glue, and fabricated six-layer (ABACAD) cylinder diffusion cloak and background media E. The simulation results show that the six-layer mass diffusion cloak can protect concrete against chloride ions penetration, while the experiment results show that the concentration gradients are parallel and equal outside the outer circle in the diffusion flux lines, the iso-concentration lines are parallel outside the outer circle, and the concentration gradients in the inner circle are smaller than those outside the outer circle.
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Affiliation(s)
- Lunwu Zeng
- Jiangsu Key Laboratory for Intelligent Agricultural Equipment, College of Engineering, Nanjing Agricultural University, Nanjing 210031, China
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244
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Otsuka PH, Nanri K, Matsuda O, Tomoda M, Profunser DM, Veres IA, Danworaphong S, Khelif A, Benchabane S, Laude V, Wright OB. Broadband evolution of phononic-crystal-waveguide eigenstates in real- and k-spaces. Sci Rep 2013; 3:3351. [PMID: 24284621 PMCID: PMC3842087 DOI: 10.1038/srep03351] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 11/07/2013] [Indexed: 11/09/2022] Open
Abstract
Control of sound in phononic band-gap structures promises novel control and guiding mechanisms. Designs in photonic systems were quickly matched in phononics, and rows of defects in phononic crystals were shown to guide sound waves effectively. The vast majority of work in such phononic guiding has been in the frequency domain, because of the importance of the phononic dispersion relation in governing acoustic confinement in waveguides. However, frequency-domain studies miss vital information concerning the phase of the acoustic field and eigenstate coupling. Using a wide range of wavevectors k, we implement an ultrafast technique to probe the wave field evolution in straight and L-shaped phononic crystal surface-phonon waveguides in real- and k-space in two spatial dimensions, thus revealing the eigenstate-energy redistribution processes and the coupling between different frequency-degenerate eigenstates. Such use of k-t space is a first in acoustics, and should have other interesting applications such as acoustic-metamaterial characterization.
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Affiliation(s)
- P H Otsuka
- Division of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
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245
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Kort-Kamp WJM, Rosa FSS, Pinheiro FA, Farina C. Tuning plasmonic cloaks with an external magnetic field. PHYSICAL REVIEW LETTERS 2013; 111:215504. [PMID: 24313504 DOI: 10.1103/physrevlett.111.215504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Indexed: 06/02/2023]
Abstract
We propose a mechanism to actively tune the operation of plasmonic cloaks with an external magnetic field by investigating electromagnetic scattering by a dielectric cylinder coated with a magneto-optical shell. In the long wavelength limit, we show that the presence of a magnetic field may drastically reduce the scattering cross section at all observation angles. We demonstrate that the application of magnetic fields can modify the operation wavelength without the need of changing material and/or geometrical parameters. We also show that applied magnetic fields can reversibly switch on and off the cloak operation. These results, which could be achieved for existing magneto-optical materials, are shown to be robust to material losses, so that they may pave the way for developing actively tunable, versatile plasmonic cloaks.
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Affiliation(s)
- W J M Kort-Kamp
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro 21941-972, Rio de Janeiro, Brazil
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246
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Huang L, Chen X, Mühlenbernd H, Zhang H, Chen S, Bai B, Tan Q, Jin G, Cheah KW, Qiu CW, Li J, Zentgraf T, Zhang S. Three-dimensional optical holography using a plasmonic metasurface. Nat Commun 2013. [PMCID: PMC3868226 DOI: 10.1038/ncomms3808] [Citation(s) in RCA: 408] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Benefitting from the flexibility in engineering their optical response, metamaterials have been used to achieve control over the propagation of light to an unprecedented level, leading to highly unconventional and versatile optical functionalities compared with their natural counterparts. Recently, the emerging field of metasurfaces, which consist of a monolayer of photonic artificial atoms, has offered attractive functionalities for shaping wave fronts of light by introducing an abrupt interfacial phase discontinuity. Here we realize three-dimensional holography by using metasurfaces made of subwavelength metallic nanorods with spatially varying orientations. The phase discontinuity takes place when the helicity of incident circularly polarized light is reversed. As the phase can be continuously controlled in each subwavelength unit cell by the rod orientation, metasurfaces represent a new route towards high-resolution on-axis three-dimensional holograms with a wide field of view. In addition, the undesired effect of multiple diffraction orders usually accompanying holography is eliminated. Holographic techniques allow for the construction of 3D images by controlling the wave front of light beams. Huang et al. develop ultrathin plasmonic metasurfaces to provide 3D optical holographic image reconstruction in the visible and near-infrared regions for circularly polarized light.
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247
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Ma Q, Mei ZL, Zhu SK, Jin TY, Cui TJ. Experiments on active cloaking and illusion for Laplace equation. PHYSICAL REVIEW LETTERS 2013; 111:173901. [PMID: 24206490 DOI: 10.1103/physrevlett.111.173901] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/17/2013] [Indexed: 05/14/2023]
Abstract
In recent years, invisibility cloaks have received a lot of attention and interest. These devices are generally classified into two types: passive and active. The design and realization of passive cloaks have been intensively studied using transformation optics and plasmonic approaches. However, active cloaks are still limited to theory and numerical simulations. Here, we present the first experiment on active cloaking and propose an active illusion for the Laplace equation. We make use of a resistor network to simulate a conducting medium. Then, we surround the central region with controlled sources to protect it from outside detection. We show that by dynamically changing the controlled sources, the protected region can be cloaked or disguised as different objects (illusion). Our measurement results agree very well with numerical simulations. Compared with the passive counterparts, the active cloaking and illusion devices do not need complicated metamaterials. They are flexible, in-line controllable, and adaptable to the environment. In addition to dc electricity, the proposed method can also be used for thermodynamics and other problems governed by the Laplace equation.
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Affiliation(s)
- Qian Ma
- School of Information Science and Engineering, Lanzhou University, Lanzhou 730000, People's Republic of China
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248
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Homogeneous thermal cloak with constant conductivity and tunable heat localization. Sci Rep 2013; 3:1593. [PMID: 23549139 PMCID: PMC3615408 DOI: 10.1038/srep01593] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 03/19/2013] [Indexed: 11/08/2022] Open
Abstract
Invisible cloak has long captivated the popular conjecture and attracted intensive research in various communities of wave dynamics, e.g., optics, electromagnetics, acoustics, etc. However, their inhomogeneous and extreme parameters imposed by transformation-optic method will usually require challenging realization with metamaterials, resulting in narrow bandwidth, loss, polarization-dependence, etc. In this paper, we demonstrate that thermodynamic cloak can be achieved with homogeneous and finite conductivity only employing naturally available materials. It is demonstrated that the thermal localization inside the coating layer can be tuned and controlled robustly by anisotropy, which enables an incomplete cloak to function perfectly. Practical realization of such homogeneous thermal cloak has been suggested by using two naturally occurring conductive materials, which provides an unprecedentedly plausible way to flexibly realize thermal cloak and manipulate heat flow with phonons.
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249
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Xu Y, Gu C, Hou B, Lai Y, Li J, Chen H. Broadband asymmetric waveguiding of light without polarization limitations. Nat Commun 2013; 4:2561. [DOI: 10.1038/ncomms3561] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 09/05/2013] [Indexed: 11/09/2022] Open
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250
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Tichit PH, Burokur SN, Qiu CW, de Lustrac A. Experimental verification of isotropic radiation from a coherent dipole source via electric-field-driven LC resonator metamaterials. PHYSICAL REVIEW LETTERS 2013; 111:133901. [PMID: 24116780 DOI: 10.1103/physrevlett.111.133901] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/25/2013] [Indexed: 06/02/2023]
Abstract
It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator's gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present.
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Affiliation(s)
- Paul-Henri Tichit
- IEF, CNRS, UMR 8622, University Paris-Sud, 91405 Orsay Cedex, France
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