1
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Yin Y, Duan Q, Li J, Qiu C, Chen H. Evolution of optical vortices in gradient media and curved spaces. OPTICS LETTERS 2023; 48:315-318. [PMID: 36638446 DOI: 10.1364/ol.472963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Light propagation in gradient media and curved spaces induce intriguing phenomena, such as focusing and self-imaging, thus delivering a wide range of applications. However, these systems are limited to excitations without orbital angular momentum, which may produce unforeseen results. Here, we demonstrate the reconstructions (or called imaging to some extent) of optical vortices (OVs) in two-dimensional (2D) gradient media and three-dimensional (3D) curved spaces. We present the evolution of OVs in two types of generalized Maxwell fisheye (GMFE) lenses from the perspective of geometrical and wave optics, and use coherent perfect absorbers (CPAs) to better recover the OVs in the converging position. Furthermore, we also demonstrate such phenomena in two types of 3D compact closed manifolds-sphere and spindle-which are also called geodesic lenses. Surprisingly, the results we obtained in 3D curved spaces can be seen as a strong verification of the Poincaré-Hopf theorem. Our work provides a new, to the best of our knowledge, platform to investigate the evolution of OVs on curved surfaces.
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2
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Yang Z, Huang X. An acoustic cloaking design based on topology optimization. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:3510. [PMID: 36586879 DOI: 10.1121/10.0016493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
In this work, we explain how to utilize the topology optimization method for the design of acoustic cloaks based on the principle of scattering cancellation. To take account of the challenging fabrication restriction, we impose boundary control inside the optimization objective function and enforce hyperbolic tangent projection to minimize the gray transition regions of the optimized design. In addition, a filter based on the Helmholtz differential equation is used to remove any tiny structures due to the effect of discretized grids. Then, we fabricate the designed cloaks and conduct the experiments in a couple of representative set-ups to validate the proposed design approach. The experiments are conducted inside both air and water. We found that the current cloaking design performs much better in air than in water and reveal the associated reason. Overall, this work paves the way for the acoustic cloaking design, fabrication, and experiments for future practical applications.
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Affiliation(s)
- Zudi Yang
- State Key Laboratory of Turbulence and Complex Systems, Department of Aeronautics and Astronautics, College of Engineering, Peking University, Beijing, 100871, People's Republic of China
| | - Xun Huang
- State Key Laboratory of Turbulence and Complex Systems, Department of Aeronautics and Astronautics, College of Engineering, Peking University, Beijing, 100871, People's Republic of China
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3
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Xu C, Chu H, Luo J, Hang ZH, Wu Y, Lai Y. Three-Dimensional Electromagnetic Void Space. PHYSICAL REVIEW LETTERS 2021; 127:123902. [PMID: 34597082 DOI: 10.1103/physrevlett.127.123902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 08/04/2021] [Indexed: 06/13/2023]
Abstract
Electromagnetic void space is a medium, while geometrically occupying a finite volume of space, optically equivalent to an infinitesimal point, in which electromagnetic waves do not experience any phase accumulation. Here, we report the first realization of three-dimensional (3D) electromagnetic void space by an all-dielectric photonic crystal possessing vanishing permittivity and permeability simultaneously. The 3D electromagnetic void space offers distinctive functionalities inaccessible to its 2D or acoustic counterparts because of the fundamental changes in topology, which comes from the ascension of dimensionality as well as the transverse nature of electromagnetic waves. In particular, we demonstrate, both theoretically and experimentally, that the transmission through such a 3D void space is unaffected by its inner boundaries, but highly sensitive to the outer boundaries. This enables many applications such as the impurity "antidoping" effect, outer-boundary-controlled switching, and 3D perfect wave steering. Our work paves a road toward 3D exotic optics of an optically infinitesimal point.
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Affiliation(s)
- Changqing Xu
- Division of Computer, Electrical and Mathematical Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Hongchen Chu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jie Luo
- School of Physical Science and Technology, Soochow University, Suzhou 215006, China
| | - Zhi Hong Hang
- School of Physical Science and Technology, Soochow University, Suzhou 215006, China
| | - Ying Wu
- Division of Computer, Electrical and Mathematical Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Yun Lai
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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4
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Shi Y, Li M, Gui X, Li C, Jing X, Hong Z. High-efficiency transmissive invisibility cloaking based on all-dielectric multilayer frame structure metasurfaces. APPLIED OPTICS 2021; 60:3909-3916. [PMID: 33983329 DOI: 10.1364/ao.421319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/13/2021] [Indexed: 06/12/2023]
Abstract
Metasurfaces provide a completely new path to realize the cloaking effect due to their excellent electromagnetic wavefront manipulation. However, most previous metasurfaces realized cloaking by using phase compensation, which is limited by the reflection phase formula and can be used only for reflection mode. We use the generalized Snell's law to propose a free-space transmission stealth device, consisting of multilayer all-dielectric metasurfaces. We utilize three phase gradient all-dielectric silicon metasurfaces that, respectively, play the role of beam splitting, steering, and collection to guide incident waves around the object, thereby forming an ideal stealth area in free space. All-dielectric metasurfaces can greatly reduce transmission loss and enhance efficiency to a large extent. The advantage of choosing an all-dielectric material is that it is easy to process and more suitable in practice. Simulation results of the near field and far field prove that this cloak has a cloaking effect at 1 THz. Our work opens up a new path for transmissive stealth.
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5
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Jing X, Feng D, Tian Y, Li M, Chu C, Li C, He Y, Gan H, Hong Z. Design of two invisibility cloaks using transmissive and reflective metamaterial-based multilayer frame microstructures. OPTICS EXPRESS 2020; 28:35528-35539. [PMID: 33379666 DOI: 10.1364/oe.409137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/28/2020] [Indexed: 06/12/2023]
Abstract
Ultrathin metamaterials provide new possibilities for the realization of cloaking devices because of their ability to control electromagnetic waves. However, applications of metamaterials in cloaking devices have been limited primarily to reflection-type carpet cloaks. Hence, a transmissive free-space cloak was developed using a multilayer frame structure, wherein highly transparent metamaterials were used to guide incident waves into propagating around an object. The cloaking effect was quantitatively verified using near-field and far-field distributions. Metamaterials allow for the cloaking shells of transmissive cloaks to be developed without spatially varying extreme parameters. Moreover, a transmissive invisible cloak with metamaterial-based mirrors was designed. The design principle of this cloak with a frame structure consists of four metamaterial-based mirrors and two metal mirrors. After covered with the designed metamaterials-based mirrors cloak, the outgoing electromagnetic wave is restored greatly as if the wave passes directly through the obstacle without distortion. This cloak used the metamaterials mirrors to adjust the reflected angle, so that the outgoing electromagnetic wave does not change direction, thereby achieving the cloaking effect.
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6
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Wang Y, Sheng C, Lu YH, Gao J, Chang YJ, Pang XL, Yang TH, Zhu SN, Liu H, Jin XM. Quantum simulation of particle pair creation near the event horizon. Natl Sci Rev 2020; 7:1476-1484. [PMID: 34691544 PMCID: PMC8288817 DOI: 10.1093/nsr/nwaa111] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/26/2020] [Accepted: 02/25/2020] [Indexed: 11/13/2022] Open
Abstract
Though it is still a big challenge to unify general relativity and quantum mechanics in modern physics, the theory of quantum field related with the gravitational effect has been well developed and some striking phenomena are predicted, such as Hawking radiation. However, the direct measurement of these quantum effects under general relativity is far beyond present experiment techniques. Fortunately, the emulation of general relativity phenomena in the laboratory has become accessible in recent years. However, up to now, these simulations are limited either in classical regime or in flat space whereas quantum simulation related with general relativity is rarely involved. Here we propose and experimentally demonstrate a quantum evolution of fermions in close proximity to an artificial black hole on a photonic chip. We successfully observe the acceleration behavior, quantum creation, and evolution of a fermion pair near the event horizon: a single-photon wave packet with positive energy escapes from the black hole while negative energy is captured. Our extensible platform not only provides a route to access quantum effects related with general relativity, but also has the potentiality to investigate quantum gravity in future.
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Affiliation(s)
- Yao Wang
- Center for Integrated Quantum Information Technologies (IQIT), School of Physics and Astronomy and State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chong Sheng
- National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yong-Heng Lu
- Center for Integrated Quantum Information Technologies (IQIT), School of Physics and Astronomy and State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jun Gao
- Center for Integrated Quantum Information Technologies (IQIT), School of Physics and Astronomy and State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yi-Jun Chang
- Center for Integrated Quantum Information Technologies (IQIT), School of Physics and Astronomy and State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiao-Ling Pang
- Center for Integrated Quantum Information Technologies (IQIT), School of Physics and Astronomy and State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tian-Huai Yang
- Center for Integrated Quantum Information Technologies (IQIT), School of Physics and Astronomy and State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shi-Ning Zhu
- National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Hui Liu
- National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xian-Min Jin
- Center for Integrated Quantum Information Technologies (IQIT), School of Physics and Astronomy and State Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai 200240, China
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7
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La Spada L, Spooner C, Haq S, Hao Y. Curvilinear MetaSurfaces for Surface Wave Manipulation. Sci Rep 2019; 9:3107. [PMID: 30816130 PMCID: PMC6395592 DOI: 10.1038/s41598-018-36451-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 11/15/2018] [Indexed: 11/09/2022] Open
Abstract
Artificial sheet materials, known as MetaSurfaces, have been applied to fully control both space and surface waves due to their exceptional abilities to dynamically tailor wave fronts and polarization states, while maintaining small footprints. However, previous and current designs and manufactured MetaSurfaces are limited to specific types of surfaces. There exists no general but rigorous design methodology for MetaSurfaces with generic curvature. The aim of this paper is to develop an analytical approach to characterize the wave behavior over arbitrary curvilinear MetaSurfaces. The proposed method allows us to fully characterize all propagating and evanescent wave modes from the MetaSurfaces. We will validate the proposed technique by designing, realizing and testing an ultrathin MetaSurface cloak for surface waves. Good results are obtained in terms of bandwidth, polarization independence and fabrication simplicity.
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Affiliation(s)
- Luigi La Spada
- School of Electronic Engineering and Computer Science Queen Mary University of London, London, E1 4NS, United Kingdom.,School of Engineering and the Built Environment, Edinburgh Napier University, 10 Colinton Rd, Edinburgh, EH10 5DT, United Kingdom
| | - Chris Spooner
- QinetiQ Ltd, Cody Technology Park Ively Road, Farnborough Hampshire, GU14 0LX, United Kingdom
| | - Sajad Haq
- QinetiQ Ltd, Cody Technology Park Ively Road, Farnborough Hampshire, GU14 0LX, United Kingdom
| | - Yang Hao
- School of Electronic Engineering and Computer Science Queen Mary University of London, London, E1 4NS, United Kingdom.
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8
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Zhu J, Liu Y, Liang Z, Chen T, Li J. Elastic Waves in Curved Space: Mimicking a Wormhole. PHYSICAL REVIEW LETTERS 2018; 121:234301. [PMID: 30576206 DOI: 10.1103/physrevlett.121.234301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Indexed: 06/09/2023]
Abstract
Transformation optics (TO) can be used to investigate nontrivial spacetime structures with inhomogeneous materials. However, the extreme curvature and large refractive indices make the implementation of a wormhole challenging. By considering flexural waves on a curved plate with geometric curvature, the stringent material requirement can be relaxed, and we demonstrate a two-dimensional analog of a wormhole using homogeneous materials within a curved laboratory frame. TO is used to understand wave propagation in such a curved space. This curved elastic space approach allows us to investigate not only geodesics but also wave redirection, tunneling, and virtual caustics of the wormhole, and will be useful to develop curvature-driven wave front shaping in general.
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Affiliation(s)
- Jian Zhu
- School of Mechanical Engineering and State Key Laboratory of Strength & Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Yongquan Liu
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Zixian Liang
- College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, China
| | - Tianning Chen
- School of Mechanical Engineering and State Key Laboratory of Strength & Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China
| | - Jensen Li
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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9
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Isotropic Backward Waves Supported by a Spiral Array Metasurface. Sci Rep 2018; 8:7098. [PMID: 29740039 PMCID: PMC5940691 DOI: 10.1038/s41598-018-25469-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/11/2018] [Indexed: 11/21/2022] Open
Abstract
A planar metallic metasurface formed of spiral elements is shown to support an isotropic backward wave over a narrow band of microwave frequencies. The magnetic field of this left-handed mode is mapped experimentally using a near-field scanning technique, allowing the anti-parallel group and phase velocities to be directly visualised. The corresponding dispersion relation and isofrequency contours are obtained through Fourier transformation of the field images.
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10
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Definite photon deflections of topological defects in metasurfaces and symmetry-breaking phase transitions with material loss. Nat Commun 2018; 9:4271. [PMID: 30323279 PMCID: PMC6189048 DOI: 10.1038/s41467-018-06718-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 09/14/2018] [Indexed: 11/24/2022] Open
Abstract
Combination of topology and general relativity can lead to some profound and farsighted predictions. It is well known that symmetry breaking of the Higgs vacuum field in the early universe possibly induced topological defects in space-time, whose nontrivial effects can provide some clues about the universe’s origin. Here, by using an artificial waveguide bounded with rotational metasurface, the nontrivial effects of a topological defect of spacetime are experimentally emulated. The photon deflection in the topological waveguide has a robust definite angle that does not depend on the location and momentum of incident photons. This is remarkably different from the random optical scattering in trivial space. By including material loss such a topological effect can be well understood from the symmetry breaking of photonic modes. Our technique provides a platform to investigate topological gravity in optical systems. This method can also be extended to obtain many other novel topological photonic devices. Photonic structures can be used to simulate fundamental physical phenomena like the optical analog of gravity. Here, the authors use metasurface-engineered waveguides to emulate the optical effects of a topological defect on space-time.
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11
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Cao T, Wei CW, Cen MJ, Guo B, Kim YJ, Zhang S, Qiu CW. A reprogrammable multifunctional chalcogenide guided-wave lens. NANOSCALE 2018; 10:17053-17059. [PMID: 29869667 DOI: 10.1039/c8nr02100g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The transformation optics (TO) technique, which establishes an equivalence between a curved space and a spatial distribution of inhomogeneous constitutive parameters, has enabled an extraordinary paradigm for manipulating wave propagation. However, extreme constitutive parameters, as well as a static nature, inherently limit the simultaneous achievement of broadband performance, ultrafast reconfigurability and versatile reprogrammable functions. Here, we integrate the TO technique with an active phase-change chalcogenide to achieve a reconfigurable multi-mode guided-wave lens. The lens is made of a Rinehart-shaped curved waveguide with an effective refractive index gradient profile through partially crystallizing Ge2Sb2Te5. Upon changing the bias time of the external voltage imparted to the Ge2Sb2Te5 segments, the refractive index gradient profile can be tuned with a transformative platform for various functions for visible light. The electrically reprogrammable multi-mode guided-wave lens is capable of dynamically acquiring various functionalities with an ultrafast response time. Our findings may offer a significant step forward by providing a universal method to obtain ultrafast and highly versatile guided-wave manipulation, such as in Einstein rings, cloaking, Maxwell fish-eye lenses and Luneburg lenses.
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Affiliation(s)
- Tun Cao
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, 116024, China.
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12
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Chu H, Li Q, Liu B, Luo J, Sun S, Hang ZH, Zhou L, Lai Y. A hybrid invisibility cloak based on integration of transparent metasurfaces and zero-index materials. LIGHT, SCIENCE & APPLICATIONS 2018; 7:50. [PMID: 30839599 PMCID: PMC6107001 DOI: 10.1038/s41377-018-0052-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 07/02/2018] [Accepted: 07/02/2018] [Indexed: 05/14/2023]
Abstract
The invisibility cloak, a long-standing fantastic dream for humans, has become more tangible with the development of metamaterials. Recently, metasurface-based invisibility cloaks have been proposed and realized with significantly reduced thickness and complexity of the cloaking shell. However, the previous scheme is based on reflection-type metasurfaces and is thus limited to reflection geometry. In this work, by integrating the wavefront tailoring functionality of transparent metasurfaces and the wave tunneling functionality of zero-index materials, we have realized a unique type of hybrid invisibility cloak that functions in transmission geometry. The principle is general and applicable to arbitrary shapes. For experimental demonstration, we constructed a rhombic double-layer cloaking shell composed of a highly transparent metasurface and a double-zero medium consisting of dielectric photonic crystals with Dirac cone dispersions. The cloaking effect is verified by both full-wave simulations and microwave experimental results. The principle also reveals exciting possibilities for realizing skin-thick ultrathin cloaking shells in transmission geometry, which can eliminate the need for spatially varying extreme parameters. Our work paves a path for novel optical and electromagnetic devices based on the integration of metasurfaces and metamaterials.
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Affiliation(s)
- Hongchen Chu
- School of Physical Science and Technology and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 215006 Suzhou, China
| | - Qi Li
- State Key Laboratory of Surface Physics and Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, 200433 Shanghai, China
- Collaborative Innovation Center of Advanced Microstructures, 210093 Nanjing, China
| | - Bingbing Liu
- School of Physical Science and Technology and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 215006 Suzhou, China
| | - Jie Luo
- School of Physical Science and Technology and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 215006 Suzhou, China
| | - Shulin Sun
- Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing, Green Photonics and Department of Optical Science and Engineering, Fudan University, 200433 Shanghai, China
- State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 130033 Changchun, China
| | - Zhi Hong Hang
- School of Physical Science and Technology and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 215006 Suzhou, China
| | - Lei Zhou
- State Key Laboratory of Surface Physics and Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, 200433 Shanghai, China
- Collaborative Innovation Center of Advanced Microstructures, 210093 Nanjing, China
| | - Yun Lai
- School of Physical Science and Technology and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 215006 Suzhou, China
- Collaborative Innovation Center of Advanced Microstructures, 210093 Nanjing, China
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, 210093 Nanjing, China
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13
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Zhang C, Shi Z, Mao F, Yang C, Zhu X, Yang J, Zuo H, Fan R. Flexible Polyimide Nanocomposites with dc Bias Induced Excellent Dielectric Tunability and Unique Nonpercolative Negative- k toward Intrinsic Metamaterials. ACS APPLIED MATERIALS & INTERFACES 2018; 10:26713-26722. [PMID: 30004213 DOI: 10.1021/acsami.8b09063] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Intrinsic metamaterials with negative- k that originated from random-structured materials have drawn increasing attention. Currently, intrinsic negative- k was mainly achieved in percolative composites by tailoring the compositions and microstructures. Herein, plasmalike negative- k was successfully achieved in multiwalled carbon nanotubes (MWCNT)/polyimide (PI) nanocomposites via applying external dc bias which exhibited excellent capability in conveniently and accurately adjusting negative- k. Mechanism analysis indicated that the localized charges at the interfaces between MWCNT and PI became delocalized after gaining energy from the dc bias, resulting in elevated concentration of delocalized charges, and hence the enhanced negative- k. Furthermore, it is surprising to observe that negative- k also appeared in multilayer nanocomposites consisting of alternating BaTiO3/PI and PI layers, in which there was no percolative conducting network. On the basis of systematic analysis, it is proposed that the unique nonpercolative negative- k resulted from the mutual competition between plasma oscillations of delocalized charges and polarizations of localized charges. Negative- k appeared once the polarizations were overwhelmed by plasma oscillations. This work demonstrated that applying dc bias is a promising way to achieve highly tailorable negative- k. Meanwhile, the observation of unique nonpercolative negative- k and the clarification of underlying mechanisms offer new insights into negative- k metamaterials, which will greatly facilitate the exploration of high-performance electromagnetic metamaterials.
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Affiliation(s)
- Chao Zhang
- School of Materials Science and Engineering , Ocean University of China , Qingdao 266100 , China
| | - Zhicheng Shi
- School of Materials Science and Engineering , Ocean University of China , Qingdao 266100 , China
| | - Fan Mao
- School of Materials Science and Engineering , Ocean University of China , Qingdao 266100 , China
| | - Chaoqiang Yang
- School of Materials Science and Engineering , Ocean University of China , Qingdao 266100 , China
| | - Xiaotong Zhu
- School of Materials Science and Engineering , Ocean University of China , Qingdao 266100 , China
| | - Jie Yang
- School of Materials Science and Engineering , Ocean University of China , Qingdao 266100 , China
| | - Heng Zuo
- School of Materials Science and Engineering , Ocean University of China , Qingdao 266100 , China
| | - Runhua Fan
- Institute of Marine Materials Science and Engineering , Shanghai Maritime University , Shanghai 201306 , China
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14
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Zhong F, Li J, Liu H, Zhu S. Controlling Surface Plasmons Through Covariant Transformation of the Spin-Dependent Geometric Phase Between Curved Metamaterials. PHYSICAL REVIEW LETTERS 2018; 120:243901. [PMID: 29956963 DOI: 10.1103/physrevlett.120.243901] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Indexed: 06/08/2023]
Abstract
General relativity uses curved space-time to describe accelerating frames. The movement of particles in different curved space-times can be regarded as equivalent physical processes based on the covariant transformation between different frames. In this Letter, we use one-dimensional curved metamaterials to mimic accelerating particles in curved space-times. The different curved shapes of structures are used to mimic different accelerating frames. The different geometric phases along the structure are used to mimic different movements in the frame. Using the covariant principle of general relativity, we can obtain equivalent nanostructures based on space-time transformations, such as the Lorentz transformation and conformal transformation. In this way, many covariant structures can be found that produce the same surface plasmon fields when excited by spin photons. A new kind of accelerating beam, the Rindler beam, is obtained based on the Rindler metric in gravity. Very large effective indices can be obtained in such systems based on geometric-phase gradient. This general covariant design method can be extended to many other optical media.
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Affiliation(s)
- Fan Zhong
- National Laboratory of Solid State Microstructures & School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jensen Li
- School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Hui Liu
- National Laboratory of Solid State Microstructures & School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Shining Zhu
- National Laboratory of Solid State Microstructures & School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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15
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Shao Z, Yang Y, Wang Z, Yahaya M, Zheng B, Dehdashti S, Wang H, Chen H. Manipulating surface plasmon polaritons with infinitely anisotropic metamaterials. OPTICS EXPRESS 2017; 25:10515-10526. [PMID: 28468424 DOI: 10.1364/oe.25.010515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Guiding surface states through disorders recently has attracted attention of scientists from diverse backgrounds. In this work, we report a robust method to guide surface plasmon polaritons (SPPs) through arbitrary distorted metal surfaces (a kind of disorder), including slopes, bumps, and sharp corners. Almost total transmissions over a broad frequency range can be achieved by use of infinitely anisotropic metamaterials (IAMs). The SPPs are coupled into and out of the bulk modes in the IAMs, where the bulk modes are routed by altering the principle axis of the IAMs. Due to unique non-diffraction property of the IAMs, all processes are of high efficiency, which are explained from both microscopic and macroscopic perspectives. Several functional SPP devices, including adapter, cloak, and sharp bending waveguide, are presented in the simulations. Two proof-of-concept SPP devices are experimentally demonstrated, where the SPPs are mimicked by the designer SPPs at microwave frequency.
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16
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Omnidirectional surface wave cloak using an isotropic homogeneous dielectric coating. Sci Rep 2016; 6:30984. [PMID: 27492929 PMCID: PMC4974505 DOI: 10.1038/srep30984] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/24/2016] [Indexed: 11/13/2022] Open
Abstract
The field of transformation optics owes a lot of its fame to the concept of cloaking. While some experimental progress has been made towards free-space cloaking in three dimensions, the material properties required are inherently extremely difficult to achieve. The approximations that then have to be made to allow fabrication produce unsatisfactory device performance. In contrast, when surface wave systems are the focus, it has been shown that a route distinct from those used to design free-space cloaks can be taken. This results in very simple solutions that take advantage of the ability to incorporate surface curvature. Here, we provide a demonstration in the microwave regime of cloaking a bump in a surface. The distortion of the shape of the surface wave fronts due to the curvature is corrected with a suitable refractive index profile. The surface wave cloak is fabricated from a metallic backed homogeneous dielectric waveguide of varying thickness, and exhibits omnidirectional operation.
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Surface Wave Cloak from Graded Refractive Index Nanocomposites. Sci Rep 2016; 6:29363. [PMID: 27416815 PMCID: PMC4945873 DOI: 10.1038/srep29363] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/17/2016] [Indexed: 02/02/2023] Open
Abstract
Recently, a great deal of interest has been re-emerged on the possibility to manipulate surface waves, in particular, towards the THz and optical regime. Both concepts of Transformation Optics (TO) and metamaterials have been regarded as one of key enablers for such applications in applied electromagnetics. In this paper, we experimentally demonstrate for the first time a dielectric surface wave cloak from engineered gradient index materials to illustrate the possibility of using nanocomposites to control surface wave propagation through advanced additive manufacturing. The device is designed analytically and validated through numerical simulations and measurements, showing good agreement and performance as an effective surface wave cloak. The underlying design approach has much wider applications, which span from microwave to optics for the control of surface plasmon polaritons (SPPs) and radiation of nanoantennas.
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Omnidirectional optical attractor in structured gap-surface plasmon waveguide. Sci Rep 2016; 6:23514. [PMID: 27001451 PMCID: PMC4802319 DOI: 10.1038/srep23514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 03/08/2016] [Indexed: 11/08/2022] Open
Abstract
An optical attractor based on a simple and easy to fabricate structured metal-dielectric-metal (SMDM) waveguide is proposed. The structured waveguide has a variable thickness in the vicinity of an embedded microsphere and allow for adiabatic nano-focusing of gap-surface plasmon polaritons (GSPPs). We show that the proposed system acts as an omnidirectional absorber across a broad spectral range. The geometrical optics approximation is used to provide a description of the ray trajectories in the system and identify the singularity of the deflection angle at the photon sphere. The analytical theory is validated by full-wave numerical simulations demonstrating adiabatic, deep sub-wavelength focusing of GSPPs and high local field enhancement. The proposed structured waveguide is an ideal candidate for the demonstration of reflection free omnidirectional absorption of GSPP in the optical and infrared frequency ranges.
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A broadband polarization-insensitive cloak based on mode conversion. Sci Rep 2015; 5:12106. [PMID: 26175114 PMCID: PMC4502514 DOI: 10.1038/srep12106] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 06/17/2015] [Indexed: 11/20/2022] Open
Abstract
In this work, we demonstrate an one-dimensional cloak consisting of parallel-plated waveguide with two slabs of gradient index metamaterials attached to its metallic walls. In it objects are hidden without limitation of polarizations, and good performance is observed for a broadband of frequencies. The experiments at microwave frequencies are carried out, supporting the theoretical results very well. The essential principle behind the proposed cloaking device is based on mode conversion, which provides a new strategy to manipulate wave propagation.
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Abstract
Guiding surface electromagnetic waves around disorder without disturbing the wave amplitude or phase is in great demand for modern photonic and plasmonic devices, but is fundamentally difficult to realize because light momentum must be conserved in a scattering event. A partial realization has been achieved by exploiting topological electromagnetic surface states, but this approach is limited to narrow-band light transmission and subject to phase disturbances in the presence of disorder. Recent advances in transformation optics apply principles of general relativity to curve the space for light, allowing one to match the momentum and phase of light around any disorder as if that disorder were not there. This feature has been exploited in the development of invisibility cloaks. An ideal invisibility cloak, however, would require the phase velocity of light being guided around the cloaked object to exceed the vacuum speed of light--a feat potentially achievable only over an extremely narrow band. In this work, we theoretically and experimentally show that the bottlenecks encountered in previous studies can be overcome. We introduce a class of cloaks capable of remarkable broadband surface electromagnetic waves guidance around ultrasharp corners and bumps with no perceptible changes in amplitude and phase. These cloaks consist of specifically designed nonmagnetic metamaterials and achieve nearly ideal transmission efficiency over a broadband frequency range from 0(+) to 6 GHz. This work provides strong support for the application of transformation optics to plasmonic circuits and could pave the way toward high-performance, large-scale integrated photonic circuits.
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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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McManus TM, Valiente-Kroon JA, Horsley SAR, Hao Y. Illusions and cloaks for surface waves. Sci Rep 2014; 4:5977. [PMID: 25145953 PMCID: PMC4141251 DOI: 10.1038/srep05977] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 07/11/2014] [Indexed: 11/30/2022] Open
Abstract
Ever since the inception of Transformation Optics (TO), new and exciting ideas have been proposed in the field of electromagnetics and the theory has been modified to work in such fields as acoustics and thermodynamics. The most well-known application of this theory is to cloaking, but another equally intriguing application of TO is the idea of an illusion device. Here, we propose a general method to transform electromagnetic waves between two arbitrary surfaces. This allows a flat surface to reproduce the scattering behaviour of a curved surface and vice versa, thereby giving rise to perfect optical illusion and cloaking devices, respectively. The performance of the proposed devices is simulated using thin effective media with engineered material properties. The scattering of the curved surface is shown to be reproduced by its flat analogue (for illusions) and vice versa for cloaks.
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Affiliation(s)
- T M McManus
- School of Electronic Engineering and Computer Science, Queen Mary University of London, E1 4NS, England, , UK
| | - J A Valiente-Kroon
- School of Mathematical Sciences, Queen Mary University of London, E1 4NS, England, , UK
| | - S A R Horsley
- Department of Physics and Astronomy, University of Exeter, EX4 4QL, England, , UK
| | - Y Hao
- School of Electronic Engineering and Computer Science, Queen Mary University of London, E1 4NS, England, , UK
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Mitchell-Thomas RC, Quevedo-Teruel O, McManus TM, Horsley SAR, Hao Y. Lenses on curved surfaces. OPTICS LETTERS 2014; 39:3551-3554. [PMID: 24978534 DOI: 10.1364/ol.39.003551] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This Letter presents a theory that allows graded index lenses to be mapped onto arbitrary rotationally symmetric curved surfaces. Examples of the Luneburg and Maxwell fish-eye lens are given, for numerous surfaces, always resulting in isotropic permittivity requirements. The performance of these lenses is initially illustrated with full-wave simulations utilizing a waveguide structure. A transformation of the refractive index profiles is then performed to design surface-wave lenses, where the dielectric layer is not only isotropic but also homogenous, demonstrating the applicability and ease of fabrication.
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Horsley SAR, Hooper IR, Mitchell–Thomas RC, Quevedo–Teruel O. Removing singular refractive indices with sculpted surfaces. Sci Rep 2014; 4:4876. [PMID: 24786649 PMCID: PMC4007085 DOI: 10.1038/srep04876] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 04/15/2014] [Indexed: 11/23/2022] Open
Abstract
The advent of Transformation Optics established the link between geometry and material properties, and has resulted in a degree of control over electromagnetic fields that was previously impossible. For waves confined to a surface it is known that there is a simpler, but related, geometrical equivalence between the surface shape and the refractive index, and here we demonstrate that conventional devices possessing a singularity - that is, the requirement of an infinite refractive index - can be realised for waves confined to an appropriately sculpted surface. In particular, we redesign three singular omnidirectional devices: the Eaton lens, the generalized Maxwell Fish-Eye, and the invisible sphere. Our designs perfectly reproduce the behaviour of these singular devices, and can be achieved with simple isotropic media of low refractive index contrast.
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Affiliation(s)
- S. A. R. Horsley
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, United Kingdom
| | - I. R. Hooper
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, United Kingdom
| | - R. C. Mitchell–Thomas
- School of Electronic Engineering and Computer Science, Queen Mary University of London, London E1 4NS, United Kingdom
| | - O. Quevedo–Teruel
- School of Electrical Engineering, KTH Royal Institute of Technology, SE-10044, Stockholm, Sweden
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Kumar A, Fung KH, Reid MTH, Fang NX. Transformation optics scheme for two-dimensional materials. OPTICS LETTERS 2014; 39:2113-6. [PMID: 24686688 DOI: 10.1364/ol.39.002113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Two-dimensional optical materials, such as graphene, can be characterized by surface conductivity. So far, the transformation optics schemes have focused on three-dimensional properties such as permittivity ϵ and permeability μ. In this Letter, we use a scheme for transforming surface currents to highlight that the surface conductivity transforms in a way different from ϵ and μ. We use this surface conductivity transformation to demonstrate an example problem of reducing the scattering of the plasmon mode from sharp protrusions in graphene.
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