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Liu J, Shen J, Zhao D, Zhang P. Photonic passbands induced by optical fractal effect in Cantor dielectric multilayers. PLoS One 2022; 17:e0268908. [PMID: 35917299 PMCID: PMC9345341 DOI: 10.1371/journal.pone.0268908] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/11/2022] [Indexed: 11/18/2022] Open
Abstract
We investigate the splitting and incorporation of optical fractal states in one-dimensional photonic quasi-crystals. The aperiodic crystals which are composed of two different dielectrics submit to Cantor sequence. Defects in Cantor crystals can greatly enhance the localization of electric field, which induces the optical fractal effect. The number of optical fractal states increases exponentially with the generation number of Cantor sequence. Moreover, the optical fractal characteristics depend on the incident angle of light, of which the fractal states may split/incorporate by modulating the value of incident angle. This study could be utilized for band-pass filters and reflectors.
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Affiliation(s)
- Jianxia Liu
- School of Electrical and Information Engineering, Hubei University of Science and Technology, Xianning, China
| | - Jing Shen
- School of Electrical and Information Engineering, Hubei University of Science and Technology, Xianning, China
| | - Dong Zhao
- School of Electrical and Information Engineering, Hubei University of Science and Technology, Xianning, China
| | - Pu Zhang
- Research Center for the Development of Rural Education and Culture, Key Research Base of Humanities and Social Sciences in Hubei Province, Hubei University of Science and Technology, Xianning, China
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2
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Aluminum Cayley trees as scalable, broadband, multiresonant optical antennas. Proc Natl Acad Sci U S A 2022; 119:2116833119. [PMID: 35046038 PMCID: PMC8794834 DOI: 10.1073/pnas.2116833119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2021] [Indexed: 11/18/2022] Open
Abstract
Optical antennas perform the same functions for light that aerials do for radio waves; they can extract energy from a propagating electromagnetic field, and they can convert localized energy into propagating radiation. Here, we use a fractal-like design, the Cayley tree, to create optical antennas. Implementing this simple iterative design with aluminum as the antenna material, we demonstrate optical antennas with broadband operating range from energies corresponding to thermal radiation up to ultraviolet. The spatial distribution of electromagnetic energy inside the antennas is experimentally imaged using electron energy loss spectroscopy, a technique allowing direct imaging and spectroscopy at the nanoscale. Such antennas are interesting for applications including photodetection, nonlinear frequency conversion, and infrared absorption spectroscopy. An optical antenna can convert a propagative optical radiation into a localized excitation and the reciprocal. Although optical antennas can be readily created using resonant nanoparticles (metallic or dielectric) as elementary building blocks, the realization of antennas sustaining multiple resonances over a broad range of frequencies remains a challenging task. Here, we use aluminum self-similar, fractal-like structures as broadband optical antennas. Using electron energy loss spectroscopy, we experimentally evidence that a single aluminum Cayley tree, a simple self-similar structure, sustains multiple plasmonic resonances. The spectral position of these resonances is scalable over a broad spectral range spanning two decades, from ultraviolet to midinfrared. Such multiresonant structures are highly desirable for applications ranging from nonlinear optics to light harvesting and photodetection, as well as surface-enhanced infrared absorption spectroscopy.
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3
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Bellido EP, Bicket IC, Botton GA. The effects of bending on plasmonic modes in nanowires and planar structures. NANOPHOTONICS 2022; 11:305-314. [PMID: 36533260 PMCID: PMC9728462 DOI: 10.1515/nanoph-2021-0449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 12/08/2021] [Indexed: 06/16/2023]
Abstract
In this work, we investigate the effects of bends on the surface plasmon resonances in nanowires (NWs) and isolated edges of planar structures using electron energy loss spectroscopy experiments and theoretical calculations. Previous work showed that the sharp bends in NWs do not affect their resonant modes. Here, we study previously overlooked effects and analyze systematically the evolution of resonant modes for several bending angles from 30° to 180°, showing that bending can have a significant effect on the plasmonic response of a nanostructure. In NWs, the modes can experience significant energy shifts that depend on the aspect ratio of the NW and can cause mode intersection and antinode bunching. We establish the relation between NW modes and edge modes and show that bending can even induce antinode splitting in edge modes. This work demonstrates that bends in plasmonic planar nanostructures can have a profound effect on their optical response and this must be accounted for in the design of optical devices.
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Affiliation(s)
- Edson P. Bellido
- Department of Materials Science and Engineering, McMaster University, Hamilton, Canada
| | - Isobel C. Bicket
- Department of Materials Science and Engineering, McMaster University, Hamilton, Canada
- Canadian Centre for Electron Microscopy, McMaster University, Hamilton, Canada
| | - Gianluigi A. Botton
- Department of Materials Science and Engineering, McMaster University, Hamilton, Canada
- Canadian Light Source, Saskatoon, Canada
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4
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Alexander DTL, Flauraud V, Demming-Janssen F. Near-Field Mapping of Photonic Eigenmodes in Patterned Silicon Nanocavities by Electron Energy-Loss Spectroscopy. ACS NANO 2021; 15:16501-16514. [PMID: 34585583 DOI: 10.1021/acsnano.1c06065] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recently, there has been significant interest in using dielectric nanocavities for the controlled scattering of light, owing to the diverse electromagnetic modes that they support. For plasmonic systems, electron energy-loss spectroscopy (EELS) is now an established method enabling structure-optical property analysis at the scale of the nanostructure. Here, we instead test its potential for the near-field mapping of photonic eigenmodes supported in planar dielectric nanocavities, which are lithographically patterned from amorphous silicon according to standard photonic principles. By correlating results with finite element simulations, we demonstrate how many of the EELS excitations can be directly corresponded to various optical eigenmodes of interest for photonic engineering. The EELS maps present a high spatial definition, displaying intensity features that correlate precisely to the impact parameters giving the highest probability of modal excitation. Further, eigenmode characteristics translate into their EELS signatures, such as the spatially and energetically extended signal of the low Q-factor electric dipole and nodal intensity patterns emerging from excitation of toroidal and second-order magnetic modes within the nanocavity volumes. Overall, the spatial-spectral nature of the data, combined with our experimental-simulation toolbox, enables interpretation of subtle changes in the EELS response across a range of nanocavity dimensions and forms, with certain simulated resonances matching the excitation energies within ±0.01 eV. By connecting results to far-field simulations, perspectives are offered for tailoring the nanophotonic resonances via manipulating nanocavity size and shape.
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Affiliation(s)
- Duncan T L Alexander
- Electron Spectrometry and Microscopy Laboratory (LSME), Institute of Physics (IPHYS), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Valentin Flauraud
- Microsystems Laboratory (LMIS1), Microengineering Institute (IMT), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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5
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Wang X, Liu C, Gao C, Yao K, Masouleh SSM, Berté R, Ren H, Menezes LDS, Cortés E, Bicket IC, Wang H, Li N, Zhang Z, Li M, Xie W, Yu Y, Fang Y, Zhang S, Xu H, Vomiero A, Liu Y, Botton GA, Maier SA, Liang H. Self-Constructed Multiple Plasmonic Hotspots on an Individual Fractal to Amplify Broadband Hot Electron Generation. ACS NANO 2021; 15:10553-10564. [PMID: 34114794 DOI: 10.1021/acsnano.1c03218] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Plasmonic nanoparticles are ideal candidates for hot-electron-assisted applications, but their narrow resonance region and limited hotspot number hindered the energy utilization of broadband solar energy. Inspired by tree branches, we designed and chemically synthesized silver fractals, which enable self-constructed hotspots and multiple plasmonic resonances, extending the broadband generation of hot electrons for better matching with the solar radiation spectrum. We directly revealed the plasmonic origin, the spatial distribution, and the decay dynamics of hot electrons on the single-particle level by using ab initio simulation, dark-field spectroscopy, pump-probe measurements, and electron energy loss spectroscopy. Our results show that fractals with acute tips and narrow gaps can support broadband resonances (400-1100 nm) and a large number of randomly distributed hotspots, which can provide unpolarized enhanced near field and promote hot electron generation. As a proof-of-concept, hot-electron-triggered dimerization of p-nitropthiophenol and hydrogen production are investigated under various irradiations, and the promoted hot electron generation on fractals was confirmed with significantly improved efficiency.
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Affiliation(s)
- Xi Wang
- School of Materials Science and Engineering, Tianjin University, Tianjin 300350, P.R. China
- Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, Ministry of Education, Tianjin University, Tianjin 300350, P.R. China
| | - Changxu Liu
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, D-80539 München, Germany
| | - Congcong Gao
- School of Materials Science and Engineering, Tianjin University, Tianjin 300350, P.R. China
| | - Kaili Yao
- School of Materials Science and Engineering, Tianjin University, Tianjin 300350, P.R. China
| | - Seyed Shayan Mousavi Masouleh
- Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada
| | - Rodrigo Berté
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, D-80539 München, Germany
| | - Haoran Ren
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, D-80539 München, Germany
| | - Leonardo de S Menezes
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, D-80539 München, Germany
- Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife-PE, Brazil
| | - Emiliano Cortés
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, D-80539 München, Germany
| | - Isobel C Bicket
- Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada
| | - Haiyu Wang
- School of Materials Science and Engineering, Tianjin University, Tianjin 300350, P.R. China
| | - Ning Li
- School of Materials Science and Engineering, Tianjin University, Tianjin 300350, P.R. China
| | - Zhenglong Zhang
- School of Physics and Information Technology, Shaanxi Normal University, Xi'an 710061, P R. China
| | - Ming Li
- School of Materials Science and Engineering, State Key Laboratory for Power Metallurgy, Central South University, Changsha, Hunan 410083, P.R. China
| | - Wei Xie
- Key Lab of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Weijin Road 94, Tianjin 300071, P.R. China
| | - Yifu Yu
- Department of Chemistry, School of Science, Institute of Molecular Plus, Tianjin University, Tianjin, 300072, P. R. China
| | - Yurui Fang
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, P.R. China
| | - Shunping Zhang
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, P.R. China
| | - Hongxing Xu
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, P.R. China
- The Institute for Advanced Studies, Wuhan University, Wuhan 430072, P.R. China
| | - Alberto Vomiero
- Division of Materials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, S-97187 Luleå, Sweden
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, I-30172 Venezia Mestre, Italy
| | - Yongchang Liu
- State Key Lab of Hydraulic Engineering Simulation and Safety, School of Materials Science and Engineering, Tianjin University, Tianjin 300354, P.R. China
| | - Gianluigi A Botton
- Department of Materials Science and Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7, Canada
| | - Stefan A Maier
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, D-80539 München, Germany
- Department of Physics, Imperial College London, London SW7 2AZ, England
| | - Hongyan Liang
- School of Materials Science and Engineering, Tianjin University, Tianjin 300350, P.R. China
- Key Laboratory of Efficient Utilization of Low and Medium Grade Energy, Ministry of Education, Tianjin University, Tianjin 300350, P.R. China
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6
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Carvalho WOF, Mejía-Salazar JR. Surface Plasmon Resonances in Sierpinski-Like Photonic Crystal Fibers: Polarization Filters and Sensing Applications. MOLECULES (BASEL, SWITZERLAND) 2020; 25:molecules25204654. [PMID: 33065967 PMCID: PMC7587391 DOI: 10.3390/molecules25204654] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/01/2020] [Accepted: 10/09/2020] [Indexed: 12/20/2022]
Abstract
We investigate the plasmonic behavior of a fractal photonic crystal fiber, with Sierpinski-like circular cross-section, and its potential applications for refractive index sensing and multiband polarization filters. Numerical results were obtained using the finite element method through the commercial software COMSOL Multiphysics®. A set of 34 surface plasmon resonances was identified in the wavelength range from λ=630 nm to λ=1700 nm. Subsets of close resonances were noted as a consequence of similar symmetries of the surface plasmon resonance (SPR) modes. Polarization filtering capabilities are numerically shown in the telecommunication windows from the O-band to the L-band. In the case of refractive index sensing, we used the wavelength interrogation method in the wavelength range from λ=670 nm to λ=790 nm, where the system exhibited a sensitivity of S(λ)=1951.43 nm/RIU (refractive index unit). Due to the broadband capabilities of our concept, we expect that it will be useful to develop future ultra-wide band optical communication infrastructures, which are urgent to meet the ever-increasing demand for bandwidth-hungry devices.
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Seitl L, Laible F, Dickreuter S, Gollmer DA, Kern DP, Fleischer M. Miniaturized fractal optical nanoantennas defined by focused helium ion beam milling. NANOTECHNOLOGY 2020; 31:075301. [PMID: 31725410 DOI: 10.1088/1361-6528/ab5120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
It has been shown in the past that fractal geometries are beneficial for radio and communication antenna designs in terms of bandwidth and gain. Recently, this concept was extended to plasmonic nanoantennas. Here, we present a fabrication method based on electron beam lithography and focused helium ion beam milling to further miniaturize dimer nanoantennas of 0th, 1st and 2nd order Sierpiński fractals. With this state-of-the-art approach, it becomes feasible to experimentally move their resonance conditions into the sub-micron wavelength regime, while maintaining excellent pattern definition and achieving sub-10 nm gap sizes for high near-field enhancement. These highly sophisticated nanostructures are numerically simulated and analyzed by dark-field scattering spectroscopy to monitor the effects of the fractal structuring on the scattering spectra and near-field enhancement.
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Affiliation(s)
- Lisa Seitl
- Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany. Center for Light-Matter-Interaction, Sensors and Analytics LISA+, University of Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany
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8
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Zheng M, Chen Y, Liu Z, Liu Y, Wang Y, Liu P, Liu Q, Bi K, Shu Z, Zhang Y, Duan H. Kirigami-inspired multiscale patterning of metallic structures via predefined nanotrench templates. MICROSYSTEMS & NANOENGINEERING 2019; 5:54. [PMID: 31814993 PMCID: PMC6885514 DOI: 10.1038/s41378-019-0100-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 08/18/2019] [Accepted: 08/19/2019] [Indexed: 05/06/2023]
Abstract
Reliable fabrication of multiscale metallic patterns with precise geometry and size at both the nanoscale and macroscale is of importance for various applications in electronic and optical devices. The existing fabrication processes, which usually involve film deposition in combination with electron-beam patterning, are either time-consuming or offer limited precision. Inspired by the kirigami, an ancient handicraft art of paper cutting, this work demonstrates an electron-beam patterning process for multiscale metallic structures with significantly enhanced efficiency and precision. Similar to the kirigami, in which the final pattern is defined by cutting its contour in a paper and then removing the unwanted parts, we define the target multiscale structures by first creating nanotrench contours in a metallic film via an electron-beam-based process and then selectively peeling the separated film outside the contours. Compared with the conventional approach, which requires the exposure of the whole pattern, much less exposure area is needed for nanotrench contours, thus enabling reduced exposure time and enhanced geometric precision due to the mitigated proximity effect. A theoretical model based on interface mechanics allows a clear understanding of the nanotrench-assisted selective debonding behaviour in the peeling process. By using this fabrication process, multiscale metallic structures with sub-10-nm up to submillimetre features can be reliably achieved, having potential applications for anti-counterfeiting and gap-plasmon-enhanced spectroscopy.
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Affiliation(s)
- Mengjie Zheng
- School of Physics and Electronics, State Key laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, 410082 Changsha, People’s Republic of China
- College of Mechanical and Vehicle Engineering, Hunan University, 410082 Changsha, People’s Republic of China
| | - Yiqin Chen
- College of Mechanical and Vehicle Engineering, Hunan University, 410082 Changsha, People’s Republic of China
| | - Zhi Liu
- AML, Department of Engineering Mechanics; Center for Flexible Electronics Technology, Tsinghua University, 100084 Beijing, People’s Republic of China
| | - Yuan Liu
- AML, Department of Engineering Mechanics; Center for Flexible Electronics Technology, Tsinghua University, 100084 Beijing, People’s Republic of China
| | - Yasi Wang
- College of Mechanical and Vehicle Engineering, Hunan University, 410082 Changsha, People’s Republic of China
| | - Peng Liu
- College of Mechanical and Vehicle Engineering, Hunan University, 410082 Changsha, People’s Republic of China
| | - Qing Liu
- College of Mechanical and Vehicle Engineering, Hunan University, 410082 Changsha, People’s Republic of China
| | - Kaixi Bi
- School of Physics and Electronics, State Key laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, 410082 Changsha, People’s Republic of China
| | - Zhiwen Shu
- College of Mechanical and Vehicle Engineering, Hunan University, 410082 Changsha, People’s Republic of China
| | - Yihui Zhang
- AML, Department of Engineering Mechanics; Center for Flexible Electronics Technology, Tsinghua University, 100084 Beijing, People’s Republic of China
| | - Huigao Duan
- School of Physics and Electronics, State Key laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, 410082 Changsha, People’s Republic of China
- College of Mechanical and Vehicle Engineering, Hunan University, 410082 Changsha, People’s Republic of China
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9
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Wallace GQ, Lagugné-Labarthet F. Advancements in fractal plasmonics: structures, optical properties, and applications. Analyst 2019; 144:13-30. [DOI: 10.1039/c8an01667d] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Fractal nanostructures exhibit optical properties that span the visible to far-infrared and are emerging as exciting structures for plasmon-mediated applications.
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Affiliation(s)
- Gregory Q. Wallace
- Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research
- University of Western Ontario
- London
- Canada
| | - François Lagugné-Labarthet
- Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research
- University of Western Ontario
- London
- Canada
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10
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Reyes Gómez F, Porras-Montenegro N, Oliveira ON, Mejía-Salazar JR. Giant Second-Harmonic Generation in Cantor-like Metamaterial Photonic Superlattices. ACS OMEGA 2018; 3:17922-17927. [PMID: 31458384 PMCID: PMC6643366 DOI: 10.1021/acsomega.8b02837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 12/07/2018] [Indexed: 05/27/2023]
Abstract
We present a nonlinear transfer matrix method for studying the second-harmonic generation (SHG) in nonperiodic metamaterial photonic superlattices. A large enhancement of up to 5 orders of magnitude in SHG efficiency was observed for superlattices made with a Cantor-like quasiperiodic assembly of a nonlinear material and a metamaterial. The enhancement was found to depend much more on the electric field amplitude along the structure because of self-similarity effects than on the amount of nonlinear material, which opens the way to design superlattices for tailored applications in broad-band tunable lasers.
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Affiliation(s)
| | | | - Osvaldo N. Oliveira
- São
Carlos Institute of Physics, University
of São Paulo, CP 369, 13560-970 São Carlos, SP, Brazil
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11
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Trautmann S, Richard-Lacroix M, Dathe A, Schneidewind H, Dellith J, Fritzsche W, Deckert V. Plasmon response evaluation based on image-derived arbitrary nanostructures. NANOSCALE 2018; 10:9830-9839. [PMID: 29774907 DOI: 10.1039/c8nr02783h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The optical response of realistic 3D plasmonic substrates composed of randomly shaped particles of different size and interparticle distance distributions in addition to nanometer scale surface roughness is intrinsically challenging to simulate due to computational limitations. Here, we present a Finite Element Method (FEM)-based methodology that bridges in-depth theoretical investigations and experimental optical response of plasmonic substrates composed of such silver nanoparticles. Parametrized scanning electron microscopy (SEM) images of surface enhanced Raman spectroscopy (SERS) active substrate and tip-enhanced Raman spectroscopy (TERS) probes are used to simulate the far-and near-field optical response. Far-field calculations are consistent with experimental dark field spectra and charge distribution images reveal for the first time in arbitrary structures the contributions of interparticle hybridized modes such as sub-radiant and super-radiant modes that also locally organize as basic units for Fano resonances. Near-field simulations expose the spatial position-dependent impact of hybridization on field enhancement. Simulations of representative sections of TERS tips are shown to exhibit the same unexpected coupling modes. Near-field simulations suggest that these modes can contribute up to 50% of the amplitude of the plasmon resonance at the tip apex but, interestingly, have a small effect on its frequency in the visible range. The band position is shown to be extremely sensitive to particle nanoscale roughness, highlighting the necessity to preserve detailed information at both the largest and the smallest scales. To the best of our knowledge, no currently available method enables reaching such a detailed description of large scale realistic 3D plasmonic systems.
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Affiliation(s)
- S Trautmann
- Leibniz Institute of photonic technology (IPHT), Albert-Einstein-Straße 9, D-07745 Jena, Germany.
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