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Conrads L, Heßler A, Völkel L, Wilden K, Strauch A, Pries J, Wuttig M, Taubner T. Infrared Resonance Tuning of Nanoslit Antennas with Phase-Change Materials. ACS NANO 2023; 17:25721-25730. [PMID: 38085927 DOI: 10.1021/acsnano.3c11121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Phase-change materials (PCMs) have been established as prime candidates for nonvolatile resonance tuning of nanophotonic components based on a large optical contrast between their amorphous and crystalline states. Recently, the plasmonic PCM In3SbTe2 was introduced, which can be switched from an amorphous dielectric state to a crystalline metallic one over the entire infrared spectral range. While locally switching the PCM around metallic nanorod antennas has already been demonstrated, similar tuning of inverse antenna structures (nanoslits) has not yet been investigated. Here, we demonstrate optical resonance tuning of nanoslit antennas with dielectric and plasmonic PCMs. We compare two geometries with fundamentally different resonance tuning mechanisms: tuning the resonance of aluminum slit antennas by change of the refractive index (dielectric PCM Ge3Sb2Te6), and creating slit-like volumes of amorphous In3SbTe2 and modifying the slit geometry directly (plasmonic PCM In3SbTe2). While the tuning range with the plasmonic PCM is about 3.4 μm and only limited by fabrication, the resonances with the dielectric PCM feature a three times larger quality factor compared to resonances obtained with the plasmonic PCM.
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Affiliation(s)
- Lukas Conrads
- Institute of Physics (IA), RWTH Aachen University, Aachen D-52056, Germany
| | - Andreas Heßler
- Institute of Physics (IA), RWTH Aachen University, Aachen D-52056, Germany
| | - Lukas Völkel
- Institute of Physics (IA), RWTH Aachen University, Aachen D-52056, Germany
| | - Kilian Wilden
- Institute of Physics (IA), RWTH Aachen University, Aachen D-52056, Germany
| | - Achim Strauch
- Institute of Physics (IA), RWTH Aachen University, Aachen D-52056, Germany
| | - Julian Pries
- Institute of Physics (IA), RWTH Aachen University, Aachen D-52056, Germany
| | - Matthias Wuttig
- Institute of Physics (IA), RWTH Aachen University, Aachen D-52056, Germany
| | - Thomas Taubner
- Institute of Physics (IA), RWTH Aachen University, Aachen D-52056, Germany
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2
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Damasceno GHB, Carvalho WOF, Mejía-Salazar JR. Design of Plasmonic Yagi-Uda Nanoantennas for Chip-Scale Optical Wireless Communications. SENSORS (BASEL, SWITZERLAND) 2022; 22:7336. [PMID: 36236435 PMCID: PMC9570515 DOI: 10.3390/s22197336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Optical wireless transmission has recently become a major cutting-edge alternative for on-chip/inter-chip communications with higher transmission speeds and improved power efficiency. Plasmonic nanoantennas, the building blocks of this new nanoscale communication paradigm, require precise design to have directional radiation and improved communication ranges. Particular interest has been paid to plasmonic Yagi-Uda, i.e., the optical analog of the conventional Radio Frequency (RF) Yagi-Uda design, which may allow directional radiation of plasmonic fields. However, in contrast to the RF model, an overall design strategy for the directional and optimized front-to-back ratio of the radiated far-field patterns is lacking. In this work, a guide for the optimized design of Yagi-Uda plasmonic nanoantennas is shown. In particular, five different design conditions are used to study the effects of sizes and spacing between the constituent parts (made of Au). Importantly, it is numerically demonstrated (using the scattered fields) that closely spaced nanoantenna elements are not appropriated for directional light-to-plasmon conversion/radiation. In contrast, if the elements of the nanoantenna are widely spaced, the structure behaves like a one-dimensional array of nanodipoles, producing a funnel-like radiation pattern (not suitable for on-chip wireless optical transmission). Therefore, based on the results here, it can be concluded that the constituent metallic rib lengths must be optimized to exhibit the resonance at the working wavelength, whilst their separations should follow the relation λeff/π, where λeff indicates the effective wavelength scaling for plasmonic nanostructures.
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Affiliation(s)
- Gabriel H B Damasceno
- National Institute of Telecommunications (Inatel), Santa Rita do Sapucaí 37540-000, MG, Brazil
| | - William O F Carvalho
- National Institute of Telecommunications (Inatel), Santa Rita do Sapucaí 37540-000, MG, Brazil
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3
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Wu B, Lou Y, Wu D, Min Q, Wan X, Zhang H, Yu Y, Ma J, Si G, Pang Y. Directivity-Enhanced Detection of a Single Nanoparticle Using a Plasmonic Slot Antenna. NANO LETTERS 2022; 22:2374-2380. [PMID: 35285643 DOI: 10.1021/acs.nanolett.1c04949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In situ refractive index sensors integrated with nanoaperture-based optical tweezers possess stable and sensitive responsivity to single nanoparticles. In most existing works, detection events are only identified using the total light intensity with directivity information ignored, leading to a low signal-to-noise ratio. Here, we propose to detect an optically trapped 20 nm silica particle by monitoring directivity of a plasmonic antenna. The main and secondary radiation lobes of the antenna reverse upon trapping because the particle-induced perturbation negates the relative phase between two antenna elements, leading to a significant change of the antenna front-to-back ratio. As a result, we obtain a signal-to-noise ratio of 20, with an order-of-magnitude improvement as compared to the intensity-only detection scheme.
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Affiliation(s)
- Bei Wu
- School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China
| | - Yuanhao Lou
- School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China
| | - Dan Wu
- School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China
| | - Qiuhong Min
- School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China
| | - Xinchen Wan
- School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China
| | - Hongyuan Zhang
- School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China
| | - Yarong Yu
- School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China
| | - Jian Ma
- School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China
| | - Gangzheng Si
- School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China
| | - Yuanjie Pang
- School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430074, China
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Zang T, Zang H, Xi Z, Du J, Wang H, Lu Y, Wang P. Asymmetric Excitation of Surface Plasmon Polaritons via Paired Slot Antennas for Angstrom Displacement Sensing. PHYSICAL REVIEW LETTERS 2020; 124:243901. [PMID: 32639811 DOI: 10.1103/physrevlett.124.243901] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/01/2020] [Indexed: 06/11/2023]
Abstract
Optical antennas enable efficient coupling between propagating light and bonding electromagnetic waves like surface plasmon polaritons (SPPs). Under the illumination of inhomogeneous optical fields, propagating SPPs mediated by multimode antennas could be spatially asymmetric and the asymmetry strongly depends on the position of the antennas relative to the illumination field. Here we develop such asymmetric excitation of SPPs through illuminating a pair of slot antennas with the (1,0) mode Hermite-Gaussian beam. The physical scenario of the interaction between the illumination optical field and the paired slot antennas are elaborated by full-wave electromagnetic simulations. We also carry out experiments to monitor the asymmetric SPPs propagation with a back-focal plane imaging technique. By retrieving the asymmetric intensity ratio of the SPP pattern in the back-focal plane image, lateral displacement of the antennas down to angstrom level is demonstrated.
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Affiliation(s)
- Tianyang Zang
- Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Haofeng Zang
- Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Zheng Xi
- Optics Research Group, Delft University of Technology, Department of Imaging Physics, Lorentzweg 1, 2628CJ Delft, The Netherlands
| | - Jing Du
- Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Han Wang
- Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Yonghua Lu
- Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
- Advanced Laser Technology Laboratory of Anhui Province, Hefei, Anhui 230026, People's Republic of China
| | - Pei Wang
- Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
- Advanced Laser Technology Laboratory of Anhui Province, Hefei, Anhui 230026, People's Republic of China
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5
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Kim HM, Kim MK. Beam steering of a single nanoantenna. OPTICS EXPRESS 2020; 28:16822-16833. [PMID: 32549496 DOI: 10.1364/oe.392999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 05/06/2020] [Indexed: 06/11/2023]
Abstract
Nanoantennas play an important role as mediators to efficiently convert free-space light into localized optical energy and vice versa. However, effective control of the beam direction of a single nanoantenna remains a great challenge. In this paper, we propose an approach to steer the beam direction of a single nanoantenna by adjusting two antenna modes with opposite phase symmetry. Our theoretical study confirmed that the combination of even- and odd-symmetric modes with a phase difference of π/2 enables effective beam steering of a single nanoantenna whose steering angle is controlled by adjusting the amplitude ratio of the two antenna modes. To implement our theory in real devices, we introduced asymmetric trapezoidal nano-slot antennas with different side air-gaps of 10 and 50 nm. The trapezoidal nanoantennas can simultaneously excite the dipole and quadrupole modes in a single nanoantenna and enables effective beam steering with an angle of greater than 35° near the resonance of the quadrupole mode. In addition, the steering angle can also be controlled by adjusting the degree of asymmetry of the trapezoidal slot structure. We believe that our beam steering method for a single nanoantenna will find many potential applications in fields such as imaging, sensing, optical communication, and quantum optics.
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6
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F. Carvalho WO, Mejía-Salazar JR. Plasmonics for Telecommunications Applications. SENSORS (BASEL, SWITZERLAND) 2020; 20:s20092488. [PMID: 32354016 PMCID: PMC7250033 DOI: 10.3390/s20092488] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/17/2020] [Accepted: 04/20/2020] [Indexed: 05/08/2023]
Abstract
Plasmonic materials, when properly illuminated with visible or near-infrared wavelengths, exhibit unique and interesting features that can be exploited for tailoring and tuning the light radiation and propagation properties at nanoscale dimensions. A variety of plasmonic heterostructures have been demonstrated for optical-signal filtering, transmission, detection, transportation, and modulation. In this review, state-of-the-art plasmonic structures used for telecommunications applications are summarized. In doing so, we discuss their distinctive roles on multiple approaches including beam steering, guiding, filtering, modulation, switching, and detection, which are all of prime importance for the development of the sixth generation (6G) cellular networks.
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Horák M, Křápek V, Hrtoň M, Konečná A, Ligmajer F, Stöger-Pollach M, Šamořil T, Paták A, Édes Z, Metelka O, Babocký J, Šikola T. Limits of Babinet's principle for solid and hollow plasmonic antennas. Sci Rep 2019; 9:4004. [PMID: 30850673 PMCID: PMC6408474 DOI: 10.1038/s41598-019-40500-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 02/18/2019] [Indexed: 11/23/2022] Open
Abstract
We present an experimental and theoretical study of Babinet’s principle of complementarity in plasmonics. We have used spatially-resolved electron energy loss spectroscopy and cathodoluminescence to investigate electromagnetic response of elementary plasmonic antenna: gold discs and complementary disc-shaped apertures in a gold layer. We have also calculated their response to the plane wave illumination. While the qualitative validity of Babinet’s principle has been confirmed, quantitative differences have been found related to the energy and quality factor of the resonances and the magnitude of related near fields. In particular, apertures were found to exhibit stronger interaction with the electron beam than solid antennas, which makes them a remarkable alternative of the usual plasmonic-antennas design. We also examine the possibility of magnetic near field imaging based on the Babinet’s principle.
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Affiliation(s)
- M Horák
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00, Brno, Czech Republic
| | - V Křápek
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00, Brno, Czech Republic. .,Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69, Brno, Czech Republic.
| | - M Hrtoň
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00, Brno, Czech Republic
| | - A Konečná
- Materials Physics Center CSIC-UPV/EHU, Paseo Manuel de Lardizabal 5, 20018, San Sebastián, Spain
| | - F Ligmajer
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00, Brno, Czech Republic.,Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69, Brno, Czech Republic
| | - M Stöger-Pollach
- University Service Centre for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10, 1040, Wien, Austria
| | - T Šamořil
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00, Brno, Czech Republic.,Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69, Brno, Czech Republic
| | - A Paták
- Institute of Scientific Instruments, Czech Academy of Sciences, Královopolská 147, 612 00, Brno, Czech Republic
| | - Z Édes
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00, Brno, Czech Republic.,Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69, Brno, Czech Republic
| | - O Metelka
- Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69, Brno, Czech Republic
| | - J Babocký
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00, Brno, Czech Republic.,Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69, Brno, Czech Republic
| | - T Šikola
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00, Brno, Czech Republic.,Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69, Brno, Czech Republic
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8
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Xiang Y, Amarie S, Cai W, Luo W, Wu W, Ren M, Zhang X, Xu J. Real-space mapping of mid-infrared near-field of Yagi-Uda antenna in the emission mode. OPTICS EXPRESS 2019; 27:5884-5892. [PMID: 30876183 DOI: 10.1364/oe.27.005884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/04/2019] [Indexed: 06/09/2023]
Abstract
By using transmission-mode, scattering-type scanning near-field optical microscopy, we characterize the mid-infrared near-field properties of a Yagi-Uda antenna in the emission mode. The underlying near-field properties, including the near-field dipole-dipole coupling between antenna elements, are clearly observed. Moreover, even though most of the radiation energy is emitted into the substrate, by adopting two detector antennas, we managed to verify the unidirectionality and frequency-selectivity of the Yagi-Uda antenna in the air side. All the experimental results presented in this work are in good qualitative agreement with our numerical simulations. Our work on the Yagi-Uda antenna could help lead to novel methods for mid-infrared material analysis and bio-sensing. It should also be applicable in all-optical processing like radiation routers or a chromatic discriminator.
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9
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Yang H, Kim DS, Kim RHJY, Ahn JS, Kang T, Jeong J, Lee D. Magnetic Nature of Light Transmission through a 5-nm Gap. Sci Rep 2018; 8:2751. [PMID: 29426882 PMCID: PMC5807359 DOI: 10.1038/s41598-018-21037-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 01/18/2018] [Indexed: 11/08/2022] Open
Abstract
Slot antennas have been exploited as important building blocks of optical magnetism because their radiations are invoked by the magnetic fields along the axes, as vectorial Babinet principle predicts. However, optical magnetism of a few-nanometer-width slit, for which fascinating applications are found due to the colossal field enhancement but Babinet principle fails due to the nonnegligible thickness, has not been investigated. In this paper, we demonstrated that the magnetic field plays a dominant role in light transmission through a 5-nm slit on a 150-nm-thick gold film. The 5-nm slit was fabricated by atomic layer lithography, and the transmission was investigated for various incident angles by experiment and simulation at 785-nm wavelength. We found that, due to the deep subwavelength gap width, the transmission has the same incident angle dependence as the tangential magnetic field on the metal surface and this magnetic nature of a nanogap holds up to ~100-nm width. Our analysis establishes conditions for nanogap optical magnetism and suggests new possibilities in realizing magnetic-field-driven optical nonlinearities.
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Affiliation(s)
- Hyosim Yang
- Department of Physics and Astronomy and Center for Atom Scale Electromagnetism, Seoul National University, Seoul, 08826, Republic of Korea
| | - Dai-Sik Kim
- Department of Physics and Astronomy and Center for Atom Scale Electromagnetism, Seoul National University, Seoul, 08826, Republic of Korea
| | - Richard H Joon-Yeon Kim
- Department of Physics and Astronomy and Center for Atom Scale Electromagnetism, Seoul National University, Seoul, 08826, Republic of Korea
- Ames Laboratory, U.S. Department of Energy and Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011, USA
| | - Jae Sung Ahn
- Bio-medical Photonics Research Center, Korea Photonics Technology Institute, 9 Cheomdan venture-ro 108beon-gil, Gwangju, 61007, Republic of Korea
| | - Taehee Kang
- Department of Physics and Astronomy and Center for Atom Scale Electromagnetism, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jeeyoon Jeong
- Department of Physics and Astronomy and Center for Atom Scale Electromagnetism, Seoul National University, Seoul, 08826, Republic of Korea
| | - Dukhyung Lee
- Department of Physics and Astronomy and Center for Atom Scale Electromagnetism, Seoul National University, Seoul, 08826, Republic of Korea.
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Metasurface electrode light emitting diodes with planar light control. Sci Rep 2017; 7:14753. [PMID: 29116150 PMCID: PMC5677004 DOI: 10.1038/s41598-017-15254-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/24/2017] [Indexed: 11/30/2022] Open
Abstract
The ability of metasurfaces to manipulate light at the subwavelength scale offers unprecedented functionalities for passive and active lasing devices. However, applications of metasurfaces to optical devices are rare due to fabrication difficulties. Here, we present quantum dot light emitting diodes (QDLEDs) with a metasurface-integrated metal electrode and demonstrate microscopically controlled LED emission. By incorporating slot-groove antennas into the metal electrode, we show that LED emission from randomly polarized QD sources can be polarized and directed at will. Utilizing the relation between polarization and emission direction, we also demonstrate microscopic LED beam splitting through the selective choice of polarization.
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11
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Abstract
We clarify the nature of dynamic coupling in plasmonic resonators and determine the dynamic coupling coefficient using a simple analytic model. We show that plasmonic resonators, such as subwavelength holes in a metal film which can be treated as bound charge oscillators, couple to each other through the retarded interaction of oscillating screened charges. Our dynamic coupling model offers, for the first time, a quantitative analytic description of the fundamental symmetric and anti-symmetric modes of coupled resonators which agrees with experimental results. Our model also reveals that plasmonic electromagnetically induced transparency arises in any coupled resonators of slightly unequal lengths, as confirmed by a rigorous numerical calculation and experiments.
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Broadband nanophotonic wireless links and networks using on-chip integrated plasmonic antennas. Sci Rep 2016; 6:19490. [PMID: 26783033 PMCID: PMC4725999 DOI: 10.1038/srep19490] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/14/2015] [Indexed: 11/25/2022] Open
Abstract
Owing to their high capacity and flexibility, broadband wireless communications have been widely employed in radio and microwave regimes, playing indispensable roles in our daily life. Their optical analogs, however, have not been demonstrated at the nanoscale. In this paper, by exploiting plasmonic nanoantennas, we demonstrate the complete design of broadband wireless links and networks in the realm of nanophotonics. With a 100-fold enhancement in power transfer superior to previous designs as well as an ultrawide bandwidth that covers the entire telecommunication wavelength range, such broadband nanolinks and networks are expected to pave the way for future optical integrated nanocircuits.
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13
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Light scattering of rectangular slot antennas: parallel magnetic vector vs perpendicular electric vector. Sci Rep 2016; 6:18935. [PMID: 26740335 PMCID: PMC4704062 DOI: 10.1038/srep18935] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/01/2015] [Indexed: 11/29/2022] Open
Abstract
We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet’s principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet’s principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.
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14
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Directional radiation of Babinet-inverted optical nanoantenna integrated with plasmonic waveguide. Sci Rep 2015; 5:11832. [PMID: 26135115 PMCID: PMC4488836 DOI: 10.1038/srep11832] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 06/05/2015] [Indexed: 11/23/2022] Open
Abstract
We present a Babinet-inverted optical nanoantenna integrated with a plasmonic waveguide. Using an integrated nanoantenna, we can couple the plasmon guide mode in a metal-insulator-metal (MIM) structure into the resonant antenna feed directly. The resonantly excited feed slot then radiates to free space and generates a magnetic dipole-like far-field pattern. The coupling efficiency of the integrated nanoantenna is calculated as being approximately 19% using a three-dimensional finite-difference time-domain (3D FDTD) simulation. By adding an auxiliary groove structure along with the feed, the radiation direction can be controlled similar to an optical Yagi-Uda antenna. We also determine, both theoretically and experimentally, that groove depth plays a significant role to function groove structure as a reflector or a director. The demonstrated Babinet-inverted optical nanoantenna integrated with a plasmonic waveguide can be used as a “plasmonic via” in plasmonic nanocircuits.
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Zhao C, Liu Y, Yang J, Zhang J. Single-molecule detection and radiation control in solutions at high concentrations via a heterogeneous optical slot antenna. NANOSCALE 2014; 6:9103-9109. [PMID: 24976558 DOI: 10.1039/c4nr01407c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We designed a heterogeneous optical slot antenna (OSA) that is capable of detecting single molecules in solutions at high concentrations, where most biological processes occur. A heterogeneous OSA consists of a rectangular nanoslot fabricated on heterogeneous metallic films formed by sequential deposition of gold and aluminum on a glass substrate. The rectangular nanoslot gives rise to large field and fluorescence enhancement for single molecules. The near-field intensity inside a heterogeneous OSA is 170 times larger than that inside an aluminum zero-mode waveguide (ZMW), and the fluorescence emission rate of a molecule inside the heterogeneous OSA is about 70 times higher than that of the molecule in free space. Our proposed heterogeneous optical antenna enables excellent balance between performance and cost. The design takes into account the practical experimental conditions so that the parameters chosen in the simulation are well within the reach of current nano-fabrication technologies. Our results can be used as a direct guidance for designing high-performance, low-cost plasmonic nanodevices for the study of bio-molecule and enzyme dynamics at the single-molecule level.
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Affiliation(s)
- Chenglong Zhao
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing, 100871, China
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