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Agulto VC, Ling Z, Zhao Z, Feng S, Kato K, Haga M, Mag-Usara VK, Yoshimura M, Nakajima M. Design and fabrication of a microcoil metamaterial absorber for the sub-terahertz region. OPTICS LETTERS 2023; 48:6324-6327. [PMID: 38039258 DOI: 10.1364/ol.502614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/09/2023] [Indexed: 12/03/2023]
Abstract
The development of electromagnetic wave absorbers operating in the sub-terahertz (sub-THz) region is necessary in 6G communications. We designed and fabricated a sub-THz metamaterial absorber based on metal microcoils embedded and periodically arranged in a dielectric substrate. The microcoil parameters were optimized by calculating the electromagnetic response of the metamaterial using finite element analysis. An actual metamaterial was then fabricated based on the optimized parameters and characterized using THz time-domain spectroscopy. Our microcoil absorber exhibits an absorptance of >80% and a high shielding performance at about 250 GHz. The resonance frequency can be precisely adjusted by modifying the microcoil array dimensions.
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Lee G, Maeng I, Kang C, Oh MK, Kee CS. Strong polarization-dependent terahertz modulation of aligned Ag nanowires on Si substrate. OPTICS EXPRESS 2018; 26:13677-13685. [PMID: 29801390 DOI: 10.1364/oe.26.013677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 05/08/2018] [Indexed: 06/08/2023]
Abstract
Optically tunable, strong polarization-dependent transmission of terahertz pulses through aligned Ag nanowires on a Si substrate is demonstrated. Terahertz pulses primarily pass through the Ag nanowires and the transmittance is weakly dependent on the angle between the direction of polarization of the terahertz pulse and the direction of nanowire alignment. However, the transmission of a terahertz pulse through optically excited materials strongly depends on the polarization direction. The extinction ratio increases as the power of the pumping laser increases. The enhanced polarization dependency is explained by the redistribution of photocarriers, which accelerates the sintering effect along the direction of alignment of the Ag nanowires. The photocarrier redistribution effect is examined by the enhancement of terahertz emission from the sample. Oblique metal nanowires on Si could be utilized for designing optically tunable terahertz polarization modulators.
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Ma X, Pu M, Li X, Guo Y, Gao P, Luo X. Meta-Chirality: Fundamentals, Construction and Applications. NANOMATERIALS (BASEL, SWITZERLAND) 2017; 7:E116. [PMID: 28513560 PMCID: PMC5449997 DOI: 10.3390/nano7050116] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 05/09/2017] [Accepted: 05/10/2017] [Indexed: 11/19/2022]
Abstract
Chiral metamaterials represent a special type of artificial structures that cannot be superposed to their mirror images. Due to the lack of mirror symmetry, cross-coupling between electric and magnetic fields exist in chiral mediums and present unique electromagnetic characters of circular dichroism and optical activity, which provide a new opportunity to tune polarization and realize negative refractive index. Chiral metamaterials have attracted great attentions in recent years and have given rise to a series of applications in polarization manipulation, imaging, chemical and biological detection, and nonlinear optics. Here we review the fundamental theory of chiral media and analyze the construction principles of some typical chiral metamaterials. Then, the progress in extrinsic chiral metamaterials, absorbing chiral metamaterials, and reconfigurable chiral metamaterials are summarized. In the last section, future trends in chiral metamaterials and application in nonlinear optics are introduced.
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Affiliation(s)
- Xiaoliang Ma
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, P. O. Box 350, Chengdu 610209, China.
| | - Mingbo Pu
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, P. O. Box 350, Chengdu 610209, China.
| | - Xiong Li
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, P. O. Box 350, Chengdu 610209, China.
| | - Yinghui Guo
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, P. O. Box 350, Chengdu 610209, China.
| | - Ping Gao
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, P. O. Box 350, Chengdu 610209, China.
| | - Xiangang Luo
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, P. O. Box 350, Chengdu 610209, China.
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Baig SA, Boland JL, Damry DA, Tan HH, Jagadish C, Joyce HJ, Johnston MB. An Ultrafast Switchable Terahertz Polarization Modulator Based on III-V Semiconductor Nanowires. NANO LETTERS 2017; 17:2603-2610. [PMID: 28334532 DOI: 10.1021/acs.nanolett.7b00401] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Progress in the terahertz (THz) region of the electromagnetic spectrum is undergoing major advances, with advanced THz sources and detectors being developed at a rapid pace. Yet, ultrafast THz communication is still to be realized, owing to the lack of practical and effective THz modulators. Here, we present a novel ultrafast active THz polarization modulator based on GaAs semiconductor nanowires arranged in a wire-grid configuration. We utilize an optical pump-terahertz probe spectroscopy system and vary the polarization of the optical pump beam to demonstrate ultrafast THz modulation with a switching time of less than 5 ps and a modulation depth of -8 dB. We achieve an extinction of over 13% and a dynamic range of -9 dB, comparable to microsecond-switchable graphene- and metamaterial-based THz modulators, and surpassing the performance of optically switchable carbon nanotube THz polarizers. We show a broad bandwidth for THz modulation between 0.1 and 4 THz. Thus, this work presents the first THz modulator which combines not only a large modulation depth but also a broad bandwidth and picosecond time resolution for THz intensity and phase modulation, making it an ideal candidate for ultrafast THz communication.
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Affiliation(s)
- Sarwat A Baig
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Jessica L Boland
- Department of Physics, Clarendon Laboratory, University of Oxford , Parks Road, Oxford, OX1 3PU, United Kingdom
| | - Djamshid A Damry
- Department of Physics, Clarendon Laboratory, University of Oxford , Parks Road, Oxford, OX1 3PU, United Kingdom
| | - H Hoe Tan
- Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University , Canberra, Australian Capital Territory 2601, Australia
| | - Chennupati Jagadish
- Department of Electronic Materials Engineering, Research School of Physics and Engineering, Australian National University , Canberra, Australian Capital Territory 2601, Australia
| | - Hannah J Joyce
- Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Michael B Johnston
- Department of Physics, Clarendon Laboratory, University of Oxford , Parks Road, Oxford, OX1 3PU, United Kingdom
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Xiao YY, Lu SF. Terahertz circular fiber polarizers using suspended-core spiral fibers. APPLIED OPTICS 2017; 56:558-562. [PMID: 28157919 DOI: 10.1364/ao.56.000558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A terahertz (THz) fiber circular polarizer based on suspended core fibers is proposed and analyzed. The THz mode guides within a subwavelength-scale core, which is suspended in a polymer tube. The dry air inner cladding not only suppresses the absorption loss of the device but also supports the leaky cladding modes. The circularly polarized core mode with the same handedness of the grating couples to the leaky cladding modes suffers from loss near resonant frequencies due to the spiral structure of the fiber. The principles and characteristics of the proposed circular polarizer are theoretically derived. Parameters that have influence on the performances are analyzed by numerical simulations. Simulation results show that the proposed THz fiber polarizer exhibits a broad single circular polarization bandwidth and a relatively low absorption loss.
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Nouman MT, Hwang JH, Jang JH. Ultrathin Terahertz Quarter-wave plate based on Split Ring Resonator and Wire Grating hybrid Metasurface. Sci Rep 2016; 6:39062. [PMID: 27958358 PMCID: PMC5153656 DOI: 10.1038/srep39062] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 11/16/2016] [Indexed: 12/28/2022] Open
Abstract
Planar metasurface based quarter-wave plates offer various advantages over conventional waveplates in terms of compactness, flexibility and simple fabrication; however they offer very narrow bandwidth of operation. Here, we demonstrate a planar terahertz (THz) metasurface capable of linear to circular polarization conversion and vice versa in a wide frequency range. The proposed metasurface is based on horizontally connected split ring resonators and is realized on an ultrathin (0.05λ) zeonor substrate. The fabricated quarter waveplate realizes linear to circular polarization conversion in two broad frequency bands comprising 0.64–0.82 THz and 0.96–1.3 THz with an insertion loss ranging from −3.9 to −10 dB. By virtue of ultrathin sub wavelength thickness, the proposed waveplate design is well suited for application in near field THz optical systems. Additionally, the proposed metasurface design offers novel transmission phase characteristics that present further opportunities to realize dynamic polarization control of incident waves.
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Affiliation(s)
- Muhammad Tayyab Nouman
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, 1 OryongdongBuk-gu, Gwangju 500-712, South Korea
| | - Ji Hyun Hwang
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, 1 OryongdongBuk-gu, Gwangju 500-712, South Korea
| | - Jae-Hyung Jang
- School of Electrical Engineering and Computer Science, Gwangju Institute of Science and Technology, 1 OryongdongBuk-gu, Gwangju 500-712, South Korea
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Dynamical manipulation of electromagnetic polarization using anisotropic meta-mirror. Sci Rep 2016; 6:30771. [PMID: 27469028 PMCID: PMC4965767 DOI: 10.1038/srep30771] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/08/2016] [Indexed: 11/17/2022] Open
Abstract
Polarization control of electromagnetic wave is very important in many fields. Here, we propose an active meta-mirror to dynamically manipulate electromagnetic polarization state at a broad band. This meta-mirror is composed of a double-layered metallic pattern backed by a metallic flat plate, and the active elements of PIN diodes are integrated into the meta-atom to control the reflection phase difference between two orthogonal polarization modes. Through switching the operating state of the PIN diodes, the meta-mirror is expected to achieve three polarization states which are left-handed, right-handed circular polarizations and linear polarization, respectively. We fabricated this active meta-mirror and validated its polarization conversion performance by measurement. The linearly polarized incident wave can be dynamically converted to right-handed or left-handed circular polarization in the frequency range between 3.4 and 8.8 GHz with the average loss of 1 dB. Furthermore, it also can keep its initial linear polarization state.
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Aschaffenburg DJ, Williams MRC, Schmuttenmaer CA. Terahertz spectroscopic polarimetry of generalized anisotropic media composed of Archimedean spiral arrays: Experiments and simulations. J Chem Phys 2016; 144:174705. [DOI: 10.1063/1.4947469] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel J. Aschaffenburg
- Department of Chemistry, Yale University, 225 Prospect St., P.O. Box 208107, New Haven, Connecticut 06520-8107, USA
| | - Michael R. C. Williams
- Department of Chemistry, Yale University, 225 Prospect St., P.O. Box 208107, New Haven, Connecticut 06520-8107, USA
| | - Charles A. Schmuttenmaer
- Department of Chemistry, Yale University, 225 Prospect St., P.O. Box 208107, New Haven, Connecticut 06520-8107, USA
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Zhang W, Wang Y, Wen X, Zhang Z. Giant circular dichroism induced by silver nanocuboid heterodimers. APPLIED OPTICS 2015; 54:9359-9363. [PMID: 26560593 DOI: 10.1364/ao.54.009359] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Metallic nanocuboid heterodimers are proposed to generate a giant circular dichroism (CD) effect. Two cuboids in the heterodimers have different heights. The dipole and quadrupole charge oscillation modes in the cuboids occur under left- and right-handed circular polarizations. The height difference generates phase difference between charge oscillations in the two cuboids. The two charge oscillations and the phase difference between them are consistent with the Born-Kuhn model for the CD effect. The CD effect of the nanocuboid heterodimers can be tuned by changing the structural parameters of the nanocuboid heterodimers, especially the height difference between two cuboids. The results of this research are not only useful for designing plasmonic structures to generate the CD effect but also for understanding the physical mechanisms of the CD effect.
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Nondispersive optical activity of meshed helical metamaterials. Nat Commun 2014; 5:5435. [DOI: 10.1038/ncomms6435] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 10/01/2014] [Indexed: 11/09/2022] Open
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Spirulina-templated metal microcoils with controlled helical structures for THz electromagnetic responses. Sci Rep 2014; 4:4919. [PMID: 24815190 PMCID: PMC4017220 DOI: 10.1038/srep04919] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 04/22/2014] [Indexed: 11/08/2022] Open
Abstract
Microstructures in nature are ultrafine and ordered in biological roles, which have attracted material scientists. Spirulina forms three-dimensional helical microstructure, one of remarkable features in nature beyond our current processing technology such as lithography in terms of mass-productivity and structural multiplicity. Spirulina varies its diameter, helical pitch, and/or length against growing environment. This unique helix is suggestive of a tiny electromagnetic coil, if composed of electro-conductive metal, which brought us main concept of this work. Here, we describe the biotemplating process onto Spirulina surface to fabricate metal microcoils. Structural parameters of the microcoil can be controlled by the cultivation conditions of Spirulina template and also purely one-handed microcoil can be fabricated. A microcoil dispersion sheet exhibited optically active response attributed to structural resonance in terahertz-wave region.
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Zhang P, Zhao M, Wu L, Lu Z, Xie Z, Zheng Y, Duan J, Yang Z. Giant circular polarization conversion in layer-by-layer nonchiral metamaterial. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2013; 30:1714-1718. [PMID: 24323251 DOI: 10.1364/josaa.30.001714] [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 studied numerically the transmission properties of a kind of layer-by-layer nonchiral metamaterial. Simulation results show that under certain off-normal incidence, giant circular polarization conversion occurs for both the right and left circularly polarized waves with a roughly 1 GHz operation band. Meanwhile, the copolarization transmissions are almost suppressed to zero, leading to the high purity circular polarization transformation. This phenomenon of giant circular polarization conversion is assumed to suffer from the strong magnetic response, which is illustrated by the surface current distributions of the structure. Compared with chiral structures, this nonchiral structure is easier to design and fabricate and is expected to be used as a promising circular polarization transformer.
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Zhang P, Yang Z, Zhao M, Wu L, Lu Z, Cheng Y, Gong R, Zheng Y, Duan J. Similar structures, different characteristics: circular dichroism of metallic helix arrays with single-, double-, and triple-helical structures. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2013; 30:677-681. [PMID: 23595328 DOI: 10.1364/josaa.30.000677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We fabricated three-dimensional metallic helix arrays with single-, double-, and triple-helical structures. The transmission performances with the normal incident angle were measured in the microwave frequency of 12-18 GHz. For the single- and double-helical structures, giant circular dichroism with fairly wide bands is observed in the transmission spectra. However, the triple-helical structure does not exhibit circular dichroism. Based on the phenomenon of circular dichroism, the single- and double-helical structures can be used as broadband circular polarizers in the microwave region, but triple-helical ones cannot. The experiments have a good agreement with our simulation results, which were studied by the finite-difference time domain method.
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Affiliation(s)
- Peng Zhang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
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Ma X, Huang C, Pu M, Hu C, Feng Q, Luo X. Multi-band circular polarizer using planar spiral metamaterial structure. OPTICS EXPRESS 2012; 20:16050-8. [PMID: 22772295 DOI: 10.1364/oe.20.016050] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A multi-band circular polarizer is proposed by using multi layered planar spiral metamaterial structure in analogy with classic spiral antenna. At three distinct resonant frequencies, the incident linearly polarized wave with electric field paralleling to one specific direction is transformed into left/right-handed circularly polarized waves through electric field coupling. Measured and simulated results show that right-handed circularly polarized wave is produced at 13.33 GHz and 16.75 GHz while left-handed circularly polarized wave is obtained at 15.56 GHz. The surface current distributions are studied to investigate the transformation behavior for both circular polarizations. The relationship between the resonant positions and the structure parameters is discussed as well.
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Affiliation(s)
- Xiaoliang Ma
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Science, P.O.box 350, Chengdu 610209, China
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Yasumatsu N, Watanabe S. Precise real-time polarization measurement of terahertz electromagnetic waves by a spinning electro-optic sensor. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:023104. [PMID: 22380076 DOI: 10.1063/1.3683570] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We propose and develop a method to quickly and precisely determine the polarization direction of coherent terahertz electromagnetic waves generated by femtosecond laser pulses. The measurement system consists of a conventional terahertz time-domain spectroscopy system with the electro-optic (EO) sampling method, but we add a new functionality in the EO crystal which is continuously rotating with the angular frequency ω. We find a simple yet useful formulation of the EO signal as a function of the crystal orientation, which enables a lock-in-like detection of both the electric-field amplitude and the absolute polarization direction of the terahertz waves with respect to the probe laser pulse polarization direction at the same time. The single measurement finishes around two periods of the crystal rotations (∼21 ms), and we experimentally prove that the accuracy of the polarization measurement does not suffer from the long-term amplitude fluctuation of the terahertz pulses. Distribution of the measured polarization directions by repeating the measurements is excellently fitted by a gaussian distribution function with a standard deviation of σ = 0.56°. The developed technique is useful for the fast direct determination of the polarization state of the terahertz electromagnetic waves for polarization imaging applications as well as the precise terahertz Faraday or Kerr rotation spectroscopy.
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Affiliation(s)
- Naoya Yasumatsu
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan.
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