1
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Luo Y, Ye W, Zhou L, Xie J. Manipulating terahertz guided wave excitation with Fabry-Perot cavity-assisted metasurfaces. OPTICS EXPRESS 2024; 32:21216-21229. [PMID: 38859481 DOI: 10.1364/oe.525377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 05/13/2024] [Indexed: 06/12/2024]
Abstract
Metasurfaces are emerging as powerful tools for manipulating complex light fields, offering enhanced control in free space and on-chip waveguide applications. Their ability to customize refractive indices and dispersion properties opens up new possibilities in light guiding, yet their efficiency in exciting guided waves, particularly through metallic structures, is not fully explored. Here, we present a new method for exciting terahertz (THz) guided waves using Fabry-Perot (FP) cavity-assisted metasurfaces that enable spin-selective directional coupling and mode selection. Our design uses a substrate-free ridge silicon THz waveguide with air cladding and a supporting slab, incorporating placed metallic metasurfaces to exploit their unique interaction with the guided waves. With the silicon thin layer and air serving as an FP cavity, THz waves enter from the bottom of the device, thereby intensifying the impact of the metasurfaces. The inverse-structured complementary metasurface could enhance excitation performance. We demonstrate selective excitation of TE00 and TE10 modes with directional control, confirmed through simulations and experimental validations using a THz vector network analyzer (VNA) system. This work broadens the potential of metasurfaces for advanced THz waveguide technologies.
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2
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Canós Valero A, Shamkhi HK, Kupriianov AS, Weiss T, Pavlov AA, Redka D, Bobrovs V, Kivshar Y, Shalin AS. Superscattering emerging from the physics of bound states in the continuum. Nat Commun 2023; 14:4689. [PMID: 37542069 PMCID: PMC10403603 DOI: 10.1038/s41467-023-40382-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 07/25/2023] [Indexed: 08/06/2023] Open
Abstract
We study the Mie-like scattering from an open subwavelength resonator made of a high-index dielectric material, when its parameters are tuned to the regime of interfering resonances. We uncover a novel mechanism of superscattering, closely linked to strong coupling of the resonant modes and described by the physics of bound states in the continuum (BICs). We demonstrate that the enhanced scattering occurs due to constructive interference described by the Friedrich-Wintgen mechanism of interfering resonances, allowing to push the scattering cross section of a multipole resonance beyond the currently established limit. We develop a general non-Hermitian model to describe interfering resonances of the quasi-normal modes, and study subwavelength dielectric nonspherical resonators exhibiting avoided crossing resonances associated with quasi-BIC states. We confirm our theoretical findings by a scattering experiment conducted in the microwave frequency range. Our results reveal a new strategy to boost scattering from non-Hermitian systems, suggesting important implications for metadevices.
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Affiliation(s)
- Adrià Canós Valero
- Institute of Physics, University of Graz, and NAWI Graz, 8010, Graz, Austria.
- ITMO University, St. Petersburg, 197101, Russia.
| | - Hadi K Shamkhi
- ITMO University, St. Petersburg, 197101, Russia
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Republic of Singapore
| | | | - Thomas Weiss
- Institute of Physics, University of Graz, and NAWI Graz, 8010, Graz, Austria
| | | | - Dmitrii Redka
- Electrotechnical University LETI, St. Petersburg, 197376, Russia
| | - Vjaceslavs Bobrovs
- Riga Technical University, Institute of Telecommunications, Riga, 1048, Latvia
| | - Yuri Kivshar
- Nonlinear Physics Centre, Research School of Physics, Australian National University, Canberra, ACT, 2601, Australia.
| | - Alexander S Shalin
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia.
- MSU, Faculty of Physics, Moscow, 119991, Russia.
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3
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Yang Y, Seong J, Choi M, Park J, Kim G, Kim H, Jeong J, Jung C, Kim J, Jeon G, Lee KI, Yoon DH, Rho J. Integrated metasurfaces for re-envisioning a near-future disruptive optical platform. LIGHT, SCIENCE & APPLICATIONS 2023; 12:152. [PMID: 37339970 DOI: 10.1038/s41377-023-01169-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 02/16/2023] [Accepted: 04/24/2023] [Indexed: 06/22/2023]
Abstract
Metasurfaces have been continuously garnering attention in both scientific and industrial fields, owing to their unprecedented wavefront manipulation capabilities using arranged subwavelength artificial structures. To date, research has mainly focused on the full control of electromagnetic characteristics, including polarization, phase, amplitude, and even frequencies. Consequently, versatile possibilities of electromagnetic wave control have been achieved, yielding practical optical components such as metalenses, beam-steerers, metaholograms, and sensors. Current research is now focused on integrating the aforementioned metasurfaces with other standard optical components (e.g., light-emitting diodes, charged-coupled devices, micro-electro-mechanical systems, liquid crystals, heaters, refractive optical elements, planar waveguides, optical fibers, etc.) for commercialization with miniaturization trends of optical devices. Herein, this review describes and classifies metasurface-integrated optical components, and subsequently discusses their promising applications with metasurface-integrated optical platforms including those of augmented/virtual reality, light detection and ranging, and sensors. In conclusion, this review presents several challenges and prospects that are prevalent in the field in order to accelerate the commercialization of metasurfaces-integrated optical platforms.
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Affiliation(s)
- Younghwan Yang
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Junhwa Seong
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Minseok Choi
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Junkyeong Park
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Gyeongtae Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Hongyoon Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Junhyeon Jeong
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Chunghwan Jung
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Joohoon Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Gyoseon Jeon
- Research Institute of Industrial Science and Technology (RIST), Pohang, 37673, Republic of Korea
| | - Kyung-Il Lee
- Research Institute of Industrial Science and Technology (RIST), Pohang, 37673, Republic of Korea
| | - Dong Hyun Yoon
- Research Institute of Industrial Science and Technology (RIST), Pohang, 37673, Republic of Korea
| | - Junsuk Rho
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.
- POSCO-POSTECH-RIST Convergence Research Center for Flat Optics and Metaphotonics, Pohang, 37673, Republic of Korea.
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4
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McCarthy L, Verma O, Naidu GN, Bursi L, Alabastri A, Nordlander P, Link S. Chiral Plasmonic Pinwheels Exhibit Orientation-Independent Linear Differential Scattering under Asymmetric Illumination. CHEMICAL & BIOMEDICAL IMAGING 2023; 1:30-39. [PMID: 37122830 PMCID: PMC10131493 DOI: 10.1021/cbmi.2c00005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/09/2023] [Accepted: 02/14/2023] [Indexed: 05/02/2023]
Abstract
Plasmonic nanoantennas have considerably stronger polarization-dependent optical properties than their molecular counterparts, inspiring photonic platforms for enhancing molecular dichroism and providing fundamental insight into light-matter interactions. One such insight is that even achiral nanoparticles can yield strong optical activity when they are asymmetrically illuminated from a single oblique angle instead of evenly illuminated. This effect, called extrinsic chirality, results from the overall chirality of the experimental geometry and strongly depends on the orientation of the incident light. Although extrinsic chirality has been well-characterized, an analogous effect involving linear polarization sensitivity has not yet been discussed. In this study, we investigate the differential scattering of rotationally symmetric chiral plasmonic pinwheels when asymmetrically irradiated with linearly polarized light. Despite their high rotational symmetry, we observe substantial linear differential scattering that is maintained over all pinwheel orientations. We demonstrate that this orientation-independent linear differential scattering arises from the broken mirror and rotational symmetries of our overall experimental geometry. Our results underscore the necessity of considering both the rotational symmetry of the nanoantenna and the experimental setup, including illumination direction and angle, when performing plasmon-enhanced chiroptical characterizations. Our results demonstrate spectroscopic signatures of an effect analogous to extrinsic chirality for linear polarizations.
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Affiliation(s)
- Lauren
A. McCarthy
- Department
of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Ojasvi Verma
- Department
of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Gopal Narmada Naidu
- Department
of Physics and Astronomy, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Luca Bursi
- Department
of Physics and Astronomy, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Alessandro Alabastri
- Department
of Electrical and Computer Engineering, Rice University, 6100
Main Street, Houston, Texas 77005, United States
| | - Peter Nordlander
- Department
of Physics and Astronomy, Rice University, 6100 Main Street, Houston, Texas 77005, United States
- Department
of Electrical and Computer Engineering, Rice University, 6100
Main Street, Houston, Texas 77005, United States
| | - Stephan Link
- Department
of Chemistry, Rice University, 6100 Main Street, Houston, Texas 77005, United States
- Department
of Electrical and Computer Engineering, Rice University, 6100
Main Street, Houston, Texas 77005, United States
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5
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Li F, Yang ZY, Shi JJ, He XB. Subwavelength dichroic demultiplexer based on double Fabry-Perot cavities. OPTICS EXPRESS 2022; 30:37753-37759. [PMID: 36258357 DOI: 10.1364/oe.472582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Plasmonic demultiplexers hold promise for the realization of the subwavelength and high-splitting ratio dichroic splitter and have a wide range of applications from optical communication, and manipulation to ultrafast data treatment. However, this vision has not been realized for a long time due to lacking the suitable splitting structure design, which limits its further development of integrated photonic circuits. Here, we demonstrate a plasmonic demultiplexer with subwavelength feature size (0.54 µm) and broadband spectral (620-870 nm) range, and high-splitting ratio (17 dB in experiments and 20 dB in calculations). It consists of two adjacent Fabry-Perot cavities (covered by PMMA polymer) and coupling gratings, which are integrated with the Au waveguide. The relatively simple double cavities design of our device has a simple theoretical analysis and fabrication process. Our work has relevance for various optical applications, such as multiple wavelength photodetectors and optical multichannel interconnects.
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6
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Plasmonic-Induced Transparencies in an Integrated Metaphotonic System. NANOMATERIALS 2022; 12:nano12101701. [PMID: 35630923 PMCID: PMC9146456 DOI: 10.3390/nano12101701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/16/2022] [Accepted: 04/22/2022] [Indexed: 12/10/2022]
Abstract
In this contribution, we numerically demonstrate the generation of plasmonic transparency windows in the transmission spectrum of an integrated metaphotonic device. The hybrid photonic–plasmonic structure consists of two rectangular-shaped gold nanoparticles fully embedded in the core of a multimode dielectric optical waveguide, with their major axis aligned to the electric field lines of transverse electric guided modes. We show that these transparencies arise from different phenomena depending on the symmetry of the guided modes. For the TE0 mode, the quadrupolar and dipolar plasmonic resonances of the nanoparticles are weakly coupled, and the transparency window is due to the plasmonic analogue of electromagnetically induced transparency. For the TE1 mode, the quadrupolar and dipolar resonances of the nanoparticles are strongly coupled, and the transparency is originated from the classical analogue of the Autler–Townes effect. This analysis contributes to the understanding of plasmonic transparency windows, opening new perspectives in the design of on-chip devices for optical communications, sensing, and signal filtering applications.
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Meng Y, Chen Y, Lu L, Ding Y, Cusano A, Fan JA, Hu Q, Wang K, Xie Z, Liu Z, Yang Y, Liu Q, Gong M, Xiao Q, Sun S, Zhang M, Yuan X, Ni X. Optical meta-waveguides for integrated photonics and beyond. LIGHT, SCIENCE & APPLICATIONS 2021; 10:235. [PMID: 34811345 PMCID: PMC8608813 DOI: 10.1038/s41377-021-00655-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 09/17/2021] [Accepted: 09/28/2021] [Indexed: 05/13/2023]
Abstract
The growing maturity of nanofabrication has ushered massive sophisticated optical structures available on a photonic chip. The integration of subwavelength-structured metasurfaces and metamaterials on the canonical building block of optical waveguides is gradually reshaping the landscape of photonic integrated circuits, giving rise to numerous meta-waveguides with unprecedented strength in controlling guided electromagnetic waves. Here, we review recent advances in meta-structured waveguides that synergize various functional subwavelength photonic architectures with diverse waveguide platforms, such as dielectric or plasmonic waveguides and optical fibers. Foundational results and representative applications are comprehensively summarized. Brief physical models with explicit design tutorials, either physical intuition-based design methods or computer algorithms-based inverse designs, are cataloged as well. We highlight how meta-optics can infuse new degrees of freedom to waveguide-based devices and systems, by enhancing light-matter interaction strength to drastically boost device performance, or offering a versatile designer media for manipulating light in nanoscale to enable novel functionalities. We further discuss current challenges and outline emerging opportunities of this vibrant field for various applications in photonic integrated circuits, biomedical sensing, artificial intelligence and beyond.
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Affiliation(s)
- Yuan Meng
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084, Beijing, China
| | - Yizhen Chen
- Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing and School of Information, Science and Technology, Fudan University, Shanghai, 200433, China
| | - Longhui Lu
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yimin Ding
- Department of Electrical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
| | - Andrea Cusano
- Optoelectronic Division, Department of Engineering, University of Sannio, I-82100, Benevento, Italy
| | - Jonathan A Fan
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Qiaomu Hu
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Kaiyuan Wang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhenwei Xie
- Nanophotonics Research Centre, Shenzhen Key Laboratory of Micro-Scale Optical Information Technology, Shenzhen University, Shenzhen, 518060, China
| | - Zhoutian Liu
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084, Beijing, China
| | - Yuanmu Yang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084, Beijing, China
| | - Qiang Liu
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084, Beijing, China
- Key Laboratory of Photonic Control Technology, Ministry of Education, Tsinghua University, 100084, Beijing, China
| | - Mali Gong
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084, Beijing, China
- Key Laboratory of Photonic Control Technology, Ministry of Education, Tsinghua University, 100084, Beijing, China
| | - Qirong Xiao
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, 100084, Beijing, China.
- Key Laboratory of Photonic Control Technology, Ministry of Education, Tsinghua University, 100084, Beijing, China.
| | - Shulin Sun
- Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing and School of Information, Science and Technology, Fudan University, Shanghai, 200433, China.
- Yiwu Research Institute of Fudan University, Chengbei Road, Yiwu City, 322000, Zhejiang, China.
| | - Minming Zhang
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China.
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China.
| | - Xiaocong Yuan
- Nanophotonics Research Centre, Shenzhen Key Laboratory of Micro-Scale Optical Information Technology, Shenzhen University, Shenzhen, 518060, China
| | - Xingjie Ni
- Department of Electrical Engineering, Pennsylvania State University, University Park, PA, 16802, USA
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8
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He T, Meng Y, Liu Z, Hu F, Wang R, Li D, Yan P, Liu Q, Gong M, Xiao Q. Guided mode meta-optics: metasurface-dressed waveguides for arbitrary mode couplers and on-chip OAM emitters with a configurable topological charge. OPTICS EXPRESS 2021; 29:39406-39418. [PMID: 34809306 DOI: 10.1364/oe.443186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
Metasurface has achieved fruitful results in tailoring optical fields in free space. However, a systematic investigation on applying meta-optics to completely control waveguide modes is still elusive. Here we present a comprehensive catalog to selectively and exclusively couple free space light into arbitrary high-order waveguide modes of interest, leveraging silicon metasurface-patterned silicon nitride waveguides. By simultaneously engineering the matched phase gradient of the nanoantennas and the vectorial spatial modal overlap between the antenna near-field and target waveguide mode profile, either single or multiple high-order modes are successfully launched with high purity reaching 98%. Moreover, on-chip twisted light generators are theoretically proposed with configurable OAM topological charge ℓ from -3 to +2. This work may serve as a comprehensive framework for guided mode meta-optics and motivates further applications such as versatile integrated couplers, multiplexers, and mode-division multiplexing-based communication systems.
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9
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Xie C, Huang L, Liu W, Hong W, Ding J, Wu W, Guo M. Bifocal focusing and polarization demultiplexing by a guided wave-driven metasurface. OPTICS EXPRESS 2021; 29:25709-25719. [PMID: 34614894 DOI: 10.1364/oe.431619] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Metasurfaces have shown extraordinary light-manipulation abilities, however, most of them deal with free-space waves. It is highly desirable to develop a guided wave-driven metasurface which can extract the in-plane guided modes in the waveguide and mold it into the desired out-of-plane free-space modes. In this paper, an all-dielectric guided wave-driven metasurface, composed of an array of silicon meta-atoms on top of a silicon nitride waveguide, is proposed and simulatively demonstrated. When directly driven by fundamental transverse electric (TE00) and fundamental transverse magnetic (TM00) guided modes at operation wavelength 1.55 µm, the guided wave-driven metasurface converts them into y-polarized and x-polarized free-space light, respectively, and focuses them at different focal points, with polarization extinction ratio over 27 dB, thus simultaneously realizing triple functions of coupling guided modes to free-space waves, bifocal metalens and polarization demultiplexing. Our work offers an alternate way to control light across photonic integrated devices and free-space platforms.
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10
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Zhang Y, Li Z, Liu W, Li Z, Cheng H, Tian J, Chen S. Multi-band on-chip photonic spin Hall effect and selective excitation of whispering gallery modes with metasurface-integrated microcavity. OPTICS LETTERS 2021; 46:3528-3531. [PMID: 34329216 DOI: 10.1364/ol.429940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/20/2021] [Indexed: 06/13/2023]
Abstract
We propose an approach to realize a multi-band on-chip photonic spin Hall effect and selective excitation of whispering gallery modes (WGMs) by integrating metasurfaces with microcavities. Free-space circularly polarized light with opposite spin angular momentum can effectively excite WGMs with opposite propagation directions at fixed wavelengths. Moreover, the different WGMs with different propagation directions and polarizations can be selectively excited by manipulating the number of antennas. We demonstrate that the optical properties (i.e., coupling efficiency, peak positions, and peak widths) of the proposed metasurface-integrated microcavities can be easily tailored by adjusting different geometric parameters. This study enables the realization of chiral microcavities with exciting novel functionalities, which may provide a further step in the development of photonic integrated circuits, optical sensing, and chiral optics.
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11
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Alquliah A, Elkabbash M, Zhang J, Cheng J, Guo C. Ultrabroadband, compact, polarization independent and efficient metasurface-based power splitter on lithium niobate waveguides. OPTICS EXPRESS 2021; 29:8160-8170. [PMID: 33820267 DOI: 10.1364/oe.415676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
We propose a metasurface-based Lithium Niobate waveguide power splitter with an ultrabroadband and polarization independent performance. The design consists of an array of amorphous silicon nanoantennas that partially converts the input mode to multiple output modes creating multimode interference such that the input power is equally split and directed to two branching waveguides. FDTD simulation results show that the power splitter operates with low insertion loss (< 1dB) over a bandwidth of approximately 800 nm in the near-infrared range, far exceeding the O, E, S, C, L and U optical communication bands. The metasurface is ultracompact with a total length of 2.7 µm. The power splitter demonstrates a power imbalance of less than 0.16 dB for both fundamental TE and TM modes. Our simulations show that the device efficiency exhibits high tolerance to possible fabrication imperfections.
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12
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Tanaka M, Amemiya T, Kagami H, Nishiyama N, Arai S. Control of slow-light effect in a metamaterial-loaded Si waveguide. OPTICS EXPRESS 2020; 28:23198-23208. [PMID: 32752320 DOI: 10.1364/oe.389996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
A metamaterial is an artificial material designed to control the electric permittivity and magnetic permeability freely beyond naturally existing values. A promising application is a slow-light device realized using a combination of optical waveguides and metamaterials. This paper proposes a method to dynamically control the slow-light effect in a metamaterial-loaded Si waveguide. In this method, the slow-light effect (i.e., group index) is controlled by changing the phase of the control light incident on the device from a direction opposite to that of the signal light. The group index of the device could be continuously controlled from 63.6 to 4.2 at a wavelength of 1.55 µm.
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13
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Guo X, Ding Y, Chen X, Duan Y, Ni X. Molding free-space light with guided wave-driven metasurfaces. SCIENCE ADVANCES 2020; 6:eabb4142. [PMID: 32832643 PMCID: PMC7439608 DOI: 10.1126/sciadv.abb4142] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/04/2020] [Indexed: 05/25/2023]
Abstract
Metasurfaces with unparalleled controllability of light have shown great potential to revolutionize conventional optics. However, they mainly require external light excitation, which makes it difficult to fully integrate them on-chip. On the other hand, integrated photonics enables packing optical components densely on a chip, but it has limited free-space light controllability. Here, by dressing metasurfaces onto waveguides, we molded guided waves into any desired free-space modes to achieve complex free-space functions, such as out-of-plane beam deflection and focusing. This metasurface also breaks the degeneracy of clockwise- and counterclockwise-propagating whispering gallery modes in an active microring resonator, leading to on-chip direct orbital angular momentum lasing. Our study shows a viable route toward complete control of light across integrated photonics and free-space platforms and paves a way for creating multifunctional photonic integrated devices with agile access to free space, which enables a plethora of applications in communications, remote sensing, displays, etc.
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Abstract
Photonic integrated circuits (PICs) are revolutionizing nanotechnology, with far-reaching applications in telecommunications, molecular sensing, and quantum information. PIC designs rely on mature nanofabrication processes and readily available and optimised photonic components (gratings, splitters, couplers). Hybrid plasmonic elements can enhance PIC functionality (e.g., wavelength-scale polarization rotation, nanoscale optical volumes, and enhanced nonlinearities), but most PIC-compatible designs use single plasmonic elements, with more complex circuits typically requiring ab initio designs. Here we demonstrate a modular approach to post-processes off-the-shelf silicon-on-insulator (SOI) waveguides into hybrid plasmonic integrated circuits. These consist of a plasmonic rotator and a nanofocusser, which generate the second harmonic frequency of the incoming light. We characterize each component's performance on the SOI waveguide, experimentally demonstrating intensity enhancements of more than 200 in an inferred mode area of 100 nm2, at a pump wavelength of 1320 nm. This modular approach to plasmonic circuitry makes the applications of this technology more practical.
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15
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Wei J, Lee C. Anomalous plasmon hybridization in nanoantennas near interfaces. OPTICS LETTERS 2019; 44:6041-6044. [PMID: 32628214 DOI: 10.1364/ol.44.006041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 11/18/2019] [Indexed: 06/11/2023]
Abstract
We report on an anomalous plasmon hybridization in side-by-side coupled metallic nanoantennas on top of a silicon waveguide. Contrary to the conventional perception based on Coulomb coupling, the hybridized anti-symmetric mode in our structure possesses a higher resonance frequency than the symmetric mode. This unusual phenomenon reveals a new mechanism of plasmon hybridization, namely, coupling-induced charge redistribution. Our work includes numerical simulation, experimental validation, and theoretical analysis, emphasizing the importance of dielectric interfaces in coupled plasmonic structures, and offers new possibilities for non-Hermitian systems and integrated devices.
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16
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Wiecha PR, Majorel C, Girard C, Cuche A, Paillard V, Muskens OL, Arbouet A. Design of plasmonic directional antennas via evolutionary optimization. OPTICS EXPRESS 2019; 27:29069-29081. [PMID: 31684648 DOI: 10.1364/oe.27.029069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 08/08/2019] [Indexed: 06/10/2023]
Abstract
We demonstrate inverse design of plasmonic nanoantennas for directional light scattering. Our method is based on a combination of full-field electrodynamical simulations via the Green dyadic method and evolutionary optimization (EO). Without any initial bias, we find that the geometries reproducibly found by EO work on the same principles as radio-frequency antennas. We demonstrate the versatility of our approach by designing various directional optical antennas for different scattering problems. EO-based nanoantenna design has tremendous potential for a multitude of applications like nano-scale information routing and processing or single-molecule spectroscopy. Furthermore, EO can help to derive general design rules and to identify inherent physical limitations for photonic nanoparticles and metasurfaces.
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Liu H, Zhang Q, Zhang K, Hu G, Duan H. Designing 3D Digital Metamaterial for Elastic Waves: From Elastic Wave Polarizer to Vibration Control. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2019; 6:1900401. [PMID: 31453062 PMCID: PMC6702649 DOI: 10.1002/advs.201900401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Indexed: 05/21/2023]
Abstract
Elastic wave polarizers, which can filter out linearly polarized elastic waves from hybrid elastic waves, remain a challenge since elastic waves contain both transverse and longitudinal natures. Here, a tunable, digital, locally resonant metamaterial inspired by abacus is proposed, which consists of 3D-printed octahedral frames and built-in electromagnets. By controlling current in the electromagnets, each unit cell exhibits three digital modes, where the elastic waves have different characteristics of propagation under each mode. A variety of waveguides can be formed by a combination of the three modes and desired polarization can be further filtered out from hybrid elastic waves in a tunable manner. The underlying mechanism of these polarizer-like characteristics is investigated through a combination of theoretical analysis, numerical simulation, and experimental testing. This study provides a means of filtering out the desired wave from hybrid elastic waves, and offers promise for vibration control of particle distribution and flexible structure.
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Affiliation(s)
- Huan Liu
- State Key Laboratory of Turbulence and Complex SystemsDepartment of Mechanics and Engineering ScienceBIC‐ESATCollege of EngineeringPeking universityBeijing100871China
| | - Quan Zhang
- School of Aerospace EngineeringBeijing Institute of TechnologyBeijing100081China
| | - Kai Zhang
- School of Aerospace EngineeringBeijing Institute of TechnologyBeijing100081China
- Key Laboratory of Dynamics and Control of Flight VehicleSchool of Aerospace EngineeringBeijing Institute of TechnologyBeijing100081China
| | - Gengkai Hu
- School of Aerospace EngineeringBeijing Institute of TechnologyBeijing100081China
- Key Laboratory of Dynamics and Control of Flight VehicleSchool of Aerospace EngineeringBeijing Institute of TechnologyBeijing100081China
| | - Huiling Duan
- State Key Laboratory of Turbulence and Complex SystemsDepartment of Mechanics and Engineering ScienceBIC‐ESATCollege of EngineeringPeking universityBeijing100871China
- CAPTHEDPS and IFSA Collaborative Innovation Center of MoEPeking UniversityBeijing100871China
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18
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Meng Y, Hu F, Liu Z, Xie P, Shen Y, Xiao Q, Fu X, Bae SH, Gong M. Chip-integrated metasurface for versatile and multi-wavelength control of light couplings with independent phase and arbitrary polarization. OPTICS EXPRESS 2019; 27:16425-16439. [PMID: 31252868 DOI: 10.1364/oe.27.016425] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/01/2019] [Indexed: 05/28/2023]
Abstract
While metasurfaces are now widely considered in free-space optics, their potential for coupling and tailoring guided waves is not fully explored. Here we transfer the Jones matrix method to target versatile on-chip coupling using metasurface-patterned photonic waveguides around the telecommunication wavelength of 1.55 μm, which can accommodate both propagation and Pancharatnam-Berry phase metasurfaces for guided waves. One can either encode two arbitrary and independent phase profiles to any pair of orthogonal polarizations or deploy complete control over both the phase and polarization of coupled modes. A set of design scenarios synergizing silicon nanoantennas and low-loss silicon-nitride waveguides are proposed, including directional couplers with mode-selectivity and polarization splitters with directionality ranging from 10 to 20 dB. Furthermore, our optimization method can be further extended to cover multiple working wavelengths. Exemplary on-chip color routers are also numerically demonstrated. This chip-integrated metasurface platform further translates the concept of a metasurface into photonic integrated circuits, serving as a positive paradigm for versatile and complete control over waveguide optical signals and motivating chip-scale applications such as polarization/wavelength demultiplexers, optical switches, and multifunctional mode converters.
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19
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Amemiya T, Yamasaki S, Tanaka M, Kagami H, Masuda K, Nishiyama N, Arai S. Demonstration of slow-light effect in silicon-wire waveguides combined with metamaterials. OPTICS EXPRESS 2019; 27:15007-15017. [PMID: 31163940 DOI: 10.1364/oe.27.015007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 04/04/2019] [Indexed: 06/09/2023]
Abstract
We demonstrated a novel slow-light Si-wire waveguide combined with metamaterials, which can be easily integrated with other Si photonics devices. The slow-light effect can be produced simply by placing metamaterials at an appropriate position on a Si-wire waveguide. It was confirmed that the large group index of more than 40 could be obtained because of a steep and discontinuous change of dispersion relation near the resonance frequency of metamaterials.
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Gao S, Park CS, Lee SS, Choi DY. All-dielectric metasurfaces for simultaneously realizing polarization rotation and wavefront shaping of visible light. NANOSCALE 2019; 11:4083-4090. [PMID: 30778492 DOI: 10.1039/c9nr00187e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
All-dielectric metasurfaces have shown unprecedented abilities to control light polarization and phase, yet most previous relevant studies have been mainly limited to cross-polarized schemes. This paper presents dielectric metasurfaces that incorporate distinct half-waveplate-like hydrogenated amorphous silicon nanoposts and are shown to manipulate the wavefront of transmitted visible light exhibiting controllable linear polarization angles. An anomalous beam deflector is designed, and high performances including an absolute deflection efficiency of 82%, a polarization conversion efficiency of 96%, and an extinction ratio of 37 dB are first demonstrated in the cross-polarized scheme. Furthermore, the anomalously deflected light could hold a high degree of linear polarization (>0.96), which can be continuously rotated by varying the incident polarization angle. Based on this principle, we fabricate a metalens and experimentally observe the light focusing phenomenon at the location designed for the cross-polarized light. Moreover, the rotation of the linear polarization angle corresponding to the output focused beam spot is successfully validated by tailoring the incident polarization angle. The developed metalens can therefore be treated as equivalent to the combination of a half-waveplate and focusing lens. The proposed ultra-thin dielectric metasurfaces, which do not require the alignment of multiple elements, could be used to facilitate the development of ultra-compact photonics systems.
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Affiliation(s)
- Song Gao
- Department of Electronic Engineering, Kwangwoon University, 20 Kwangwoon-ro, Nowon-gu, Seoul 01897, Republic of Korea.
| | - Chul-Soon Park
- Department of Electronic Engineering, Kwangwoon University, 20 Kwangwoon-ro, Nowon-gu, Seoul 01897, Republic of Korea.
| | - Sang-Shin Lee
- Department of Electronic Engineering, Kwangwoon University, 20 Kwangwoon-ro, Nowon-gu, Seoul 01897, Republic of Korea.
| | - Duk-Yong Choi
- Laser Physics Centre, Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia and College of Information Science and Technology, Jinan University, Guangzhou, Guangdong 510632, China
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21
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Meng Y, Hu F, Shen Y, Yang Y, Xiao Q, Fu X, Gong M. Ultracompact Graphene-Assisted Tunable Waveguide Couplers with High Directivity and Mode Selectivity. Sci Rep 2018; 8:13362. [PMID: 30190496 PMCID: PMC6127104 DOI: 10.1038/s41598-018-31555-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 07/23/2018] [Indexed: 11/24/2022] Open
Abstract
Graphene distinguishes itself as a promising candidate for realizing tunable integrated photonic devices with high flexibility. We propose a set of ultracompact tunable on-chip waveguide couplers with mode-selectivity and polarization sensitivity around the telecom wavelength of 1.55 μm, under the configuration of graphene-laminated silicon waveguides patterned with gold nanoantennas. Versatile couplings can be achieved in a widely tunable fashion within a deep-subwavelength area (210 × 210 nm2), by marrying the advantages of tight field confinement in plasmonic antennas and the largely tunable carrier density of graphene. Incident light signals can be selectively coupled into different fundamental modes with good mode quality and high directionality exceeding 25 dB. Design scenarios for asymmetric couplings are presented, where the operation wavelength can be tuned across a 107-nm range around 1.55 mm by altering the chemical potential of graphene from 0 to 1.8 eV. Furthermore, the proposed schemes can be leveraged as mode-sensitive on-chip directional waveguide signal detectors with an extinction ratio over 10 dB. Our results provide a new paradigm upon graphene-assisted tunable integrated photonic applications.
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Affiliation(s)
- Yuan Meng
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Futai Hu
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Yijie Shen
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Yuanmu Yang
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Qirong Xiao
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Xing Fu
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China
| | - Mali Gong
- State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China. .,State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing, 100084, China.
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Gao S, Lee SS, Kim ES, Choi DY. Vertically integrated visible and near-infrared metasurfaces enabling an ultra-broadband and highly angle-resolved anomalous reflection. NANOSCALE 2018; 10:12453-12460. [PMID: 29926867 DOI: 10.1039/c8nr03059f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
An optical device with minimized dimensions, which is capable of efficiently resolving an ultra-broad spectrum into a wide splitting angle but incurring no spectrum overlap, is of importance in advancing the development of spectroscopy. Unfortunately, this challenging task cannot be easily addressed through conventional geometrical or diffractive optical elements. Herein, we propose and demonstrate vertically integrated visible and near-infrared metasurfaces which render an ultra-broadband and highly angle-resolved anomalous reflection. The proposed metasurface capitalizes on a supercell that comprises two vertically concatenated trapezoid-shaped aluminum antennae, which are paired with a metallic ground plane via a dielectric layer. Under normal incidence, reflected light within a spectral bandwidth of 1000 nm ranging from λ = 456 nm to 1456 nm is efficiently angle-resolved to a single diffraction order with no spectrum overlap via the anomalous reflection, exhibiting an average reflection efficiency over 70% and a substantial angular splitting of 58°. In light of a supercell pitch of 1500 nm, to the best of our knowledge, the micron-scale bandwidth is the largest ever reported. It is noted that the substantially wide bandwidth has been accomplished by taking advantage of spectral selective vertical coupling effects between antennae and ground plane. In the visible regime, the upper antenna primarily renders an anomalous reflection by cooperating with the lower antenna, which in turn cooperates with the ground plane and produces phase variations leading to an anomalous reflection in the near-infrared regime. Misalignments between the two antennae have been particularly inspected to not adversely affect the anomalous reflection, thus guaranteeing enhanced structural tolerance of the proposed metasurface.
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Affiliation(s)
- Song Gao
- Department of Electronic Engineering, Kwangwoon University, 20 Kwangwoon-ro, Nowon-gu, Seoul 01897, Republic of Korea.
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Panmai M, Xiang J, Sun Z, Peng Y, Liu H, Liu H, Dai Q, Tie S, Lan S. All-silicon-based nano-antennas for wavelength and polarization demultiplexing. OPTICS EXPRESS 2018; 26:12344-12362. [PMID: 29801270 DOI: 10.1364/oe.26.012344] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 04/25/2018] [Indexed: 06/08/2023]
Abstract
We propose an all-silicon-based nano-antenna that functions as not only a wavelength demultiplexer but also a polarization one. The nano-antenna is composed of two silicon cuboids with the same length and height but with different widths. The asymmetric structure of the nano-antenna with respect to the electric field of the incident light induced an electric dipole component in the propagation direction of the incident light. The interference between this electric dipole and the magnetic dipole induced by the magnetic field parallel to the long side of the cuboids is exploited to manipulate the radiation direction of the nano-antenna. The radiation direction of the nano-antenna at a certain wavelength depends strongly on the phase difference between the electric and magnetic dipoles interacting coherently, offering us the opportunity to realize wavelength demultiplexing. By varying the polarization of the incident light, the interference of the magnetic dipole induced by the asymmetry of the nano-antenna and the electric dipole induced by the electric field parallel to the long side of the cuboids can also be used to realize polarization demultiplexing in a certain wavelength range. More interestingly, the interference between the dipole and quadrupole modes of the nano-antenna can be utilized to shape the radiation directivity of the nano-antenna. We demonstrate numerically that radiation with adjustable direction and high directivity can be realized in such a nano-antenna which is compatible with the current fabrication technology of silicon chips.
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24
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Chen B, Bruck R, Traviss D, Khokhar AZ, Reynolds S, Thomson DJ, Mashanovich GZ, Reed GT, Muskens OL. Hybrid Photon-Plasmon Coupling and Ultrafast Control of Nanoantennas on a Silicon Photonic Chip. NANO LETTERS 2018; 18:610-617. [PMID: 29272140 DOI: 10.1021/acs.nanolett.7b04861] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Hybrid integration of nanoplasmonic devices with silicon photonic circuits holds promise for a range of applications in on-chip sensing, field-enhanced and nonlinear spectroscopy, and integrated nanophotonic switches. Here, we demonstrate a new regime of photon-plasmon coupling by combining a silicon photonic resonator with plasmonic nanoantennas. Using principles from coherent perfect absorption, we make use of standing-wave light fields to maximize the photon-plasmon interaction strength. Precise placement of the broadband antennas with respect to the narrowband photonic racetrack modes results in controlled hybridization of only a subset of these modes. By combining antennas into groups of radiating dipoles with opposite phase, far-field scattering is effectively suppressed. We achieve ultrafast tuning of photon-plasmon hybridization including reconfigurable routing of the standing-wave input between two output ports. Hybrid photonic-plasmonic resonators provide conceptually new approaches for on-chip integrated nanophotonic devices.
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Affiliation(s)
- Bigeng Chen
- Physics and Astronomy, Faculty of Physical Sciences and Engineering, University of Southampton , Southampton SO17 1BJ, U.K
| | - Roman Bruck
- Physics and Astronomy, Faculty of Physical Sciences and Engineering, University of Southampton , Southampton SO17 1BJ, U.K
| | - Daniel Traviss
- Physics and Astronomy, Faculty of Physical Sciences and Engineering, University of Southampton , Southampton SO17 1BJ, U.K
| | - Ali Z Khokhar
- Optoelectronics Research Centre, Faculty of Physical Sciences and Engineering, University of Southampton , Southampton SO17 1BJ, U.K
| | - Scott Reynolds
- Optoelectronics Research Centre, Faculty of Physical Sciences and Engineering, University of Southampton , Southampton SO17 1BJ, U.K
| | - David J Thomson
- Optoelectronics Research Centre, Faculty of Physical Sciences and Engineering, University of Southampton , Southampton SO17 1BJ, U.K
| | - Goran Z Mashanovich
- Optoelectronics Research Centre, Faculty of Physical Sciences and Engineering, University of Southampton , Southampton SO17 1BJ, U.K
| | - Graham T Reed
- Optoelectronics Research Centre, Faculty of Physical Sciences and Engineering, University of Southampton , Southampton SO17 1BJ, U.K
| | - Otto L Muskens
- Physics and Astronomy, Faculty of Physical Sciences and Engineering, University of Southampton , Southampton SO17 1BJ, U.K
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