1
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Muhammed MM, Mokkath JH. Plasmon-induced hot carrier distribution in a composite nanosystem: role of the adsorption site. Phys Chem Chem Phys 2024; 26:9037-9050. [PMID: 38440841 DOI: 10.1039/d4cp00322e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2024]
Abstract
The generation of hot carriers (HCs) through the excitation of localized surface plasmon resonance (LSPR) in metal nanostructures is a fascinating phenomenon that fuels both fundamental and applied research. However, gaining insights into HCs at a microscopic level has posed a complex challenge, limiting our ability to create efficient nanoantennas that utilize these energized carriers. In this investigation, we employ real-time time-dependent density functional theory (rt-TDDFT) calculations to examine the creation and distribution of HCs within a model composite system consisting of a silver (Ag) nanodisk and a carbon monoxide (CO) molecule. We find that the creation and distribution of HCs are notably affected by the CO adsorption site. Particularly, when the CO molecule adsorbs onto the hollow site of the Ag nanodisk, it exhibits the highest potential among various composite systems in terms of structural stability, enhanced orbital hybridization, and HC generation and transfer. Utilizing a Gaussian laser pulse adjusted to match the LSPR frequency, we observe a marked buildup of hot electrons and hot holes on the C and O atoms. Conversely, the region encompassing the C-O bond exhibits a depletion of hot electrons and hot holes. We believe that these findings could have significant implications in the field of HC photocatalysis.
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Affiliation(s)
| | - Junais Habeeb Mokkath
- College of Integrative Studies, Abdullah Al Salem University (AASU), Block 3, Khaldiya, Kuwait.
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2
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Maciel-Escudero C, Yankovich AB, Munkhbat B, Baranov DG, Hillenbrand R, Olsson E, Aizpurua J, Shegai TO. Probing optical anapoles with fast electron beams. Nat Commun 2023; 14:8478. [PMID: 38123545 PMCID: PMC10733292 DOI: 10.1038/s41467-023-43813-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: 04/18/2023] [Accepted: 11/21/2023] [Indexed: 12/23/2023] Open
Abstract
Optical anapoles are intriguing charge-current distributions characterized by a strong suppression of electromagnetic radiation. They originate from the destructive interference of the radiation produced by electric and toroidal multipoles. Although anapoles in dielectric structures have been probed and mapped with a combination of near- and far-field optical techniques, their excitation using fast electron beams has not been explored so far. Here, we theoretically and experimentally analyze the excitation of optical anapoles in tungsten disulfide (WS2) nanodisks using Electron Energy Loss Spectroscopy (EELS) in Scanning Transmission Electron Microscopy (STEM). We observe prominent dips in the electron energy loss spectra and associate them with the excitation of optical anapoles and anapole-exciton hybrids. We are able to map the anapoles excited in the WS2 nanodisks with subnanometer resolution and find that their excitation can be controlled by placing the electron beam at different positions on the nanodisk. Considering current research on the anapole phenomenon, we envision EELS in STEM to become a useful tool for accessing optical anapoles appearing in a variety of dielectric nanoresonators.
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Affiliation(s)
- Carlos Maciel-Escudero
- Materials Physics Center, CSIC-UPV/EHU, Paseo de Manuel Lardizabal, Donostia-San Sebastián, 20018, Spain
- CIC NanoGUNE BRTA and Department of Electricity and Electronics, Tolosa Hiribidea, Donostia-San Sebastián, 20018, Spain
| | - Andrew B Yankovich
- Department of Physics, Chalmers University of Technology, 41296, Göteborg, Sweden
| | - Battulga Munkhbat
- Department of Physics, Chalmers University of Technology, 41296, Göteborg, Sweden
- Department of Photonics Engineering, Technical University of Denmark, Kgs. Lyngby, Copenhagen, 2800, Denmark
| | - Denis G Baranov
- Department of Physics, Chalmers University of Technology, 41296, Göteborg, Sweden
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia
| | - Rainer Hillenbrand
- CIC NanoGUNE BRTA and Department of Electricity and Electronics, Tolosa Hiribidea, Donostia-San Sebastián, 20018, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48011, Spain
| | - Eva Olsson
- Department of Physics, Chalmers University of Technology, 41296, Göteborg, Sweden.
| | - Javier Aizpurua
- Materials Physics Center, CSIC-UPV/EHU, Paseo de Manuel Lardizabal, Donostia-San Sebastián, 20018, Spain.
- Donostia International Physics Center, Paseo de Manuel Lardizabal, Donostia-San Sebastián, 20018, Spain.
| | - Timur O Shegai
- Department of Physics, Chalmers University of Technology, 41296, Göteborg, Sweden.
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3
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Saison-Francioso O, Lévêque G, Akjouj A, Pennec Y. Theoretical Study of Gold Nanoparticles Randomly Dispersed on a Dielectric/Gold Substrate. ACS OMEGA 2023; 8:21493-21505. [PMID: 37360435 PMCID: PMC10286086 DOI: 10.1021/acsomega.3c00342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/28/2023] [Indexed: 06/28/2023]
Abstract
We theoretically study random arrangements of cylindrical gold nanoparticles (NPs) deposited on a dielectric/gold substrate. We use two methods, namely the Finite Element Method (FEM) and the Coupled Dipole Approximation (CDA) method. The FEM is increasingly used to analyze the optical properties of NPs, but calculations for arrangements containing a large number of NPs have a high computational cost. On the contrary, the CDA has the advantage to drastically reduce the computation time and the memory demand compared to the FEM. Nevertheless, as the CDA involves modeling each NP as a single electric dipole through the polarizability tensor of a spheroidal-shaped NP, it may be an insufficiently accurate method. Therefore, the main purpose of this article is to verify the validity of using the CDA in order to analyze such a kind of nanosystems. Finally, we capitalize on this methodology to draw some tendencies between statistics of NPs' distributions and the plasmonic properties.
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4
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Rodríguez-Álvarez J, Labarta A, Idrobo JC, Dell'Anna R, Cian A, Giubertoni D, Borrisé X, Guerrero A, Perez-Murano F, Fraile Rodríguez A, Batlle X. Imaging of Antiferroelectric Dark Modes in an Inverted Plasmonic Lattice. ACS NANO 2023; 17:8123-8132. [PMID: 37089111 PMCID: PMC10173685 DOI: 10.1021/acsnano.2c11016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Plasmonic lattice nanostructures are of technological interest because of their capacity to manipulate light below the diffraction limit. Here, we present a detailed study of dark and bright modes in the visible and near-infrared energy regime of an inverted plasmonic honeycomb lattice by a combination of Au+ focused ion beam lithography with nanometric resolution, optical and electron spectroscopy, and finite-difference time-domain simulations. The lattice consists of slits carved in a gold thin film, exhibiting hotspots and a set of bright and dark modes. We proposed that some of the dark modes detected by electron energy-loss spectroscopy are caused by antiferroelectric arrangements of the slit polarizations with two times the size of the hexagonal unit cell. The plasmonic resonances take place within the 0.5-2 eV energy range, indicating that they could be suitable for a synergistic coupling with excitons in two-dimensional transition metal dichalcogenides materials or for designing nanoscale sensing platforms based on near-field enhancement over a metallic surface.
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Affiliation(s)
- Javier Rodríguez-Álvarez
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
| | - Amílcar Labarta
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
| | - Juan Carlos Idrobo
- Materials Science and Engineering Department, University of Washington, Seattle, Washington 98195, United States
| | - Rossana Dell'Anna
- Sensors & Devices Center, FBK - Bruno Kessler Foundation, via Sommarive, 18, Povo, TN 38123, Italy
| | - Alessandro Cian
- Sensors & Devices Center, FBK - Bruno Kessler Foundation, via Sommarive, 18, Povo, TN 38123, Italy
| | - Damiano Giubertoni
- Sensors & Devices Center, FBK - Bruno Kessler Foundation, via Sommarive, 18, Povo, TN 38123, Italy
| | - Xavier Borrisé
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona 08193, Spain
| | - Albert Guerrero
- Institut de Microelectrònica de Barcelona (IMB-CNM, CSIC), Bellaterra 08193, Spain
| | | | - Arantxa Fraile Rodríguez
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
| | - Xavier Batlle
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona 08028, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, Barcelona 08028, Spain
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5
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Melendez LV, Van Embden J, Connell TU, Duffy NW, Gómez DE. Optimal Geometry for Plasmonic Hot-Carrier Extraction in Metal-Semiconductor Nanocrystals. ACS NANO 2023; 17:4659-4666. [PMID: 36801851 DOI: 10.1021/acsnano.2c10892] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Plasmon-induced energy and charge transfer from metal nanostructures hold great potential for harvesting solar energy. Presently, the efficiencies of charge-carrier extraction are still low due to the competitive ultrafast mechanisms of plasmon relaxation. Using single-particle electron energy loss spectroscopy, we correlate the geometrical and compositional details of individual nanostructures to their carrier extraction efficiencies. By removing ensemble effects, we are able to show a direct structure-function relationship that permits the rational design of the most efficient metal-semiconductor nanostructures for energy harvesting applications. In particular, by developing a hybrid system comprising Au nanorods with epitaxially grown CdSe tips, we are able to control and enhance charge extraction. We show that optimal structures can have efficiencies as high as 45%. The quality of the Au-CdSe interface and the dimensions of the Au rod and CdSe tip are shown to be critical for achieving these high efficiencies of chemical interface damping.
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Affiliation(s)
- Lesly V Melendez
- School of Science, RMIT University, Melbourne, VIC 3000, Australia
| | - Joel Van Embden
- School of Science, RMIT University, Melbourne, VIC 3000, Australia
| | - Timothy U Connell
- School of Life and Environmental Sciences, Deakin University, Geelong, VIC 3220, Australia
| | - Noel W Duffy
- CSIRO Energy, Clayton South, VIC 3169, Australia
| | - Daniel E Gómez
- School of Science, RMIT University, Melbourne, VIC 3000, Australia
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6
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Zagorodnev IV, Zabolotnykh AA, Rodionov DA, Volkov VA. Two-Dimensional Plasmons in Laterally Confined 2D Electron Systems. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:975. [PMID: 36985869 PMCID: PMC10058787 DOI: 10.3390/nano13060975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 02/28/2023] [Accepted: 03/05/2023] [Indexed: 06/18/2023]
Abstract
The collective oscillations of charge density (plasmons) in conductive solids are basic excitations that determine the dynamic response of the system. In infinite two-dimensional (2D) electron systems, plasmons have gapless dispersion covering a broad spectral range from subterahertz to infrared, which is promising in light-matter applications. We discuss the state-of-the-art physics of 2D plasmons, especially in confined 2D electron systems in stripe and disk geometry, using the simplest approach for conductivity. When the metal gate is placed in the vicinity of the 2D electron system, an analytical description of the plasmon frequency and damping can be easily obtained. We also analyze gated plasmons in the disk when it was situated at various distances from the gate, and discuss in detail the nontrivial behavior of the damping. We predict that it is not a simple sum of the radiative and collisional dampings, but has a nonmonotonic dependence on the system parameters. For high-mobility 2D systems, this opens the way to achieve the maximal quality factor of plasma resonances. Lastly, we discuss the recently discovered near-gate 2D plasmons propagating along the laterally confined gate, even without applied bias voltage and having gapless dispersion when the gate has the form of a stripe, and discrete spectrum when the gate is in the form of disk. It allows for one to drive the frequency and spatial propagation of such plasmons.
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Affiliation(s)
- Igor V. Zagorodnev
- Kotelnikov Institute of Radio-Engineering and Electronics of the RAS, 125009 Moscow, Russia
| | - Andrey A. Zabolotnykh
- Kotelnikov Institute of Radio-Engineering and Electronics of the RAS, 125009 Moscow, Russia
| | - Danil A. Rodionov
- Kotelnikov Institute of Radio-Engineering and Electronics of the RAS, 125009 Moscow, Russia
- Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia
| | - Vladimir A. Volkov
- Kotelnikov Institute of Radio-Engineering and Electronics of the RAS, 125009 Moscow, Russia
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7
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Pisarra M, Gomez CV, Sindona A. Massive and massless plasmons in germanene nanosheets. Sci Rep 2022; 12:18624. [PMID: 36329251 PMCID: PMC9633710 DOI: 10.1038/s41598-022-23058-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022] Open
Abstract
Atomically thin crystals may exhibit peculiar dispersive electronic states equivalent to free charged particles of ultralight to ultraheavy masses. A rare coexistence of linear and parabolic dispersions yields correlated charge density modes exploitable for nanometric light confinement. Here, we use a time-dependent density-functional approach, under several levels of increasing accuracy, from the random-phase approximation to the Bethe-Salpeter equation formalism, to assess the role of different synthesized germanene samples as platforms for these plasmon excitations. In particular, we establish that both freestanding and some supported germenene monolayers can sustain infrared massless modes, resolved into an out-of-phase (optical) and an in-phase (acoustic) component. We further indicate precise experimental geometries that naturally host infrared massive modes, involving two different families of parabolic charge carriers. We thus show that the interplay of the massless and massive plasmons can be finetuned by applied extrinsic conditions or geometry deformations, which constitutes the core mechanism of germanene-based optoelectronic and plasmonic applications.
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Affiliation(s)
- Michele Pisarra
- Gruppo Collegato di Cosenza, Sezione dei Laboratori Nazionali di Frascati (LNF), Istituto Nazionale di Fisica Nucleare (INFN), Cubo 31C, 87036, Rende, CS, Italy
| | - Cristian Vacacela Gomez
- Facultad de Ciencias, Escuela Superior Politécnica de Chimborazo (ESPOCH), Riobamba, 060155, Ecuador
| | - Antonello Sindona
- Gruppo Collegato di Cosenza, Sezione dei Laboratori Nazionali di Frascati (LNF), Istituto Nazionale di Fisica Nucleare (INFN), Cubo 31C, 87036, Rende, CS, Italy. .,Dipartimento di Fisica, Università della Calabria, Via P. Bucci, Cubo 30C, 87036, Rende, CS, Italy.
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8
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Zhang H, Wang Q, Hou L, Xiao F, Zhao J. Selective triggering in-plane and out-of-plane dipolar modes of hexagonal Au nanoplate with the polarization of excitation beam. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:505302. [PMID: 36279871 DOI: 10.1088/1361-648x/ac9d18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
The dipolar responses of a single hexagonal Au nanoplate are investigated under the illuminations of linearly polarized beam and tightly focused radially polarized beam (RPB). It is found from the scattering spectra that the in-plane and out-of-plane electric dipole modes can be selectively triggered with a linearly polarized beam and tightly focused RPB, respectively. The features of these two dipolar modes are further confirmed in terms of electrical field and charge maps by the finite-difference time-domain simulation. Additionally, using the multipole expansion method, the existence of the out-of-plane dipole mode is further verified by the fact that thez-component of electric dipole response has a dominant contribution to the scattered power. Moreover, by combining the back focal plane imaging technique with the simulation, the appearance of in-plane and out-of-plane dipoles in the scattering pattern are clearly discerned. Our results provide an efficient method for selectively exciting the in-plane and out-of-plane dipolar modes of the nanoplate. We envision that the ease of tuning the dipolar momentum may facilitate the enhancement of the interaction between the plasmon and emitters at single-particle level.
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Affiliation(s)
- Hanmou Zhang
- Key Laboratory of Light Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, People's Republic of China
| | - Qifa Wang
- Key Laboratory of Light Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, People's Republic of China
| | - Liping Hou
- Key Laboratory of Light Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, People's Republic of China
| | - Fajun Xiao
- Key Laboratory of Light Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, People's Republic of China
| | - Jianlin Zhao
- Key Laboratory of Light Field Manipulation and Information Acquisition, Ministry of Industry and Information Technology, and Shaanxi Key Laboratory of Optical Information Technology, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, People's Republic of China
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9
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Wang N, Zhong Y, Liu H. Spontaneous emission enhancement by rotationally-symmetric optical nanoantennas: impact of radially and axially propagating surface plasmon polaritons. OPTICS EXPRESS 2022; 30:12797-12822. [PMID: 35472909 DOI: 10.1364/oe.454073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/09/2022] [Indexed: 06/14/2023]
Abstract
The excitation and radiation properties of rotationally-symmetric optical nanoantennas are independent of the azimuth angle, which enables great convenience and superior performances in practical applications. However, for rotationally-symmetric nanoantennas, the physical mechanisms behind their resonance properties remain to be clarified. In this paper, firstly, for a simple single-nanocylinder-on-mirror antenna (S-antenna), we establish a first-principles-based semianalytical model of surface plasmon polariton (SPP) by considering an intuitive multiple-scattering process of the radially-propagating gap surface plasmon (RGSP) in the nanogap and the axially-propagating surface plasmon (ASP) on the nanocylinder. The model can comprehensively reproduce all the radiation properties of the S-antenna such as the total and radiative emission rates, SPP excitation rates, and far-field radiation pattern. The model indicates that when the antenna radius is small (respectively, large), the enhancement of spontaneous emission mainly results from the resonance of ASP (respectively, RGSP). To show the wide applicability of the SPP model along with its unveiled decisive role of the RGSP and ASP in the spontaneous emission enhancement for other rotationally-symmetric nanoantennas of cylindrical shapes, we extend the SPP model to a more complex ring-nanocylinder-on-mirror antenna (R-antenna) that supports two ASPs. Moreover, to provide an explicit explanation of the resonance properties of the R-antenna, we further establish a semianalytical model for the resonant modes (called quasinormal modes, QNMs) supported by the R-antenna based on the SPP model, which quantitatively reveals the role of the RGSP and ASP in forming the antenna resonant modes and the resultant enhancement of spontaneous emission.
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10
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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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11
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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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12
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Konečná A, Li J, Edgar JH, García de Abajo FJ, Hachtel JA. Revealing Nanoscale Confinement Effects on Hyperbolic Phonon Polaritons with an Electron Beam. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2103404. [PMID: 34453472 DOI: 10.1002/smll.202103404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/29/2021] [Indexed: 06/13/2023]
Abstract
Hyperbolic phonon polaritons (HPhPs) in hexagonal boron nitride (hBN) enable the direct manipulation of mid-infrared light at nanometer scales, many orders of magnitude below the free-space light wavelength. High-resolution monochromated electron energy-loss spectroscopy (EELS) facilitates measurement of excitations with energies extending into the mid-infrared while maintaining nanoscale spatial resolution, making it ideal for detecting HPhPs. The electron beam is a precise source and probe of HPhPs, which allows the observation of nanoscale confinement in HPhP structures and directly extract hBN polariton dispersions for both modes in the bulk of the flake and modes along the edge. The measurements reveal technologically important nontrivial phenomena, such as localized polaritons induced by environmental heterogeneity, enhanced and suppressed excitation due to 2D interference, and strong modification of high-momenta excitations such as edge-confined polaritons by nanoscale heterogeneity on edge boundaries. The work opens exciting prospects for the design of real-world optical mid-infrared devices based on hyperbolic polaritons.
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Affiliation(s)
- Andrea Konečná
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
- Central European Institute of Technology, Brno University of Technology, Brno, 612 00, Czech Republic
| | - Jiahan Li
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - James H Edgar
- Tim Taylor Department of Chemical Engineering, Kansas State University, Manhattan, KS, 66506, USA
| | - F Javier García de Abajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona, 08860, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Campanys 23, Barcelona, 08010, Spain
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
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13
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García
de Abajo FJ, Di Giulio V. Optical Excitations with Electron Beams: Challenges and Opportunities. ACS PHOTONICS 2021; 8:945-974. [PMID: 35356759 PMCID: PMC8939335 DOI: 10.1021/acsphotonics.0c01950] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/17/2021] [Accepted: 02/19/2021] [Indexed: 05/20/2023]
Abstract
Free electron beams such as those employed in electron microscopes have evolved into powerful tools to investigate photonic nanostructures with an unrivaled combination of spatial and spectral precision through the analysis of electron energy losses and cathodoluminescence light emission. In combination with ultrafast optics, the emerging field of ultrafast electron microscopy utilizes synchronized femtosecond electron and light pulses that are aimed at the sampled structures, holding the promise to bring simultaneous sub-Å-sub-fs-sub-meV space-time-energy resolution to the study of material and optical-field dynamics. In addition, these advances enable the manipulation of the wave function of individual free electrons in unprecedented ways, opening sound prospects to probe and control quantum excitations at the nanoscale. Here, we provide an overview of photonics research based on free electrons, supplemented by original theoretical insights and discussion of several stimulating challenges and opportunities. In particular, we show that the excitation probability by a single electron is independent of its wave function, apart from a classical average over the transverse beam density profile, whereas the probability for two or more modulated electrons depends on their relative spatial arrangement, thus reflecting the quantum nature of their interactions. We derive first-principles analytical expressions that embody these results and have general validity for arbitrarily shaped electrons and any type of electron-sample interaction. We conclude with some perspectives on various exciting directions that include disruptive approaches to noninvasive spectroscopy and microscopy, the possibility of sampling the nonlinear optical response at the nanoscale, the manipulation of the density matrices associated with free electrons and optical sample modes, and appealing applications in optical modulation of electron beams, all of which could potentially revolutionize the use of free electrons in photonics.
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Affiliation(s)
- F. Javier García
de Abajo
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, 08860 Castelldefels, Barcelona, Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Spain
- E-mail:
| | - Valerio Di Giulio
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute
of Science and Technology, 08860 Castelldefels, Barcelona, Spain
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14
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Schmidt FP, Losquin A, Horák M, Hohenester U, Stöger-Pollach M, Krenn JR. Fundamental Limit of Plasmonic Cathodoluminescence. NANO LETTERS 2021; 21:590-596. [PMID: 33336569 PMCID: PMC7809694 DOI: 10.1021/acs.nanolett.0c04084] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/27/2020] [Indexed: 06/12/2023]
Abstract
We use cathodoluminescence (CL) spectroscopy in a transmission electron microscope to probe the radial breathing mode of plasmonic silver nanodisks. A two-mirror detection system sandwiching the sample collects the CL emission in both directions, that is, backward and forward with respect to the electron beam trajectory. We unambiguously identify a spectral shift of about 8 nm in the CL spectra acquired from both sides and show that this asymmetry is induced by the electron beam itself. By numerical simulations, we confirm the observations and identify the underlying physical effect due to the interference of the CL emission patterns of an electron-beam-induced dipole and the breathing mode. This effect can ultimately limit the achievable fidelity in CL measurements on any system involving multiple excitations and should therefore be considered with care in high-precision experiments.
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Affiliation(s)
| | - Arthur Losquin
- Thales
Research and Technology, 1 avenue Augustin Fresnel, Palaiseau 91767, France
| | - Michal Horák
- Central
European Institute of Technology, Brno University
of Technology, Brno Purkynǒva 123, 612 00, Czech Republic
| | - Ulrich Hohenester
- Institute
of Physics, University of Graz, Universitätsplatz 5, Graz 8010, Austria
| | - Michael Stöger-Pollach
- University
Service Centre for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10, Wien 1040, Austria
| | - Joachim R. Krenn
- Institute
of Physics, University of Graz, Universitätsplatz 5, Graz 8010, Austria
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15
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Mousavi M. SS, Bicket IC, Bellido EP, Soleymani L, Botton GA. Electron energy-loss spectroscopy of surface plasmon activity in wrinkled gold structures. J Chem Phys 2020; 153:224703. [DOI: 10.1063/5.0031469] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- S. Shayan Mousavi M.
- Department of Materials Science and Engineering, McMaster University, 1280 Main Street W., Hamilton, Ontario L8S 4L7, Canada
| | - Isobel C. Bicket
- Department of Materials Science and Engineering, McMaster University, 1280 Main Street W., Hamilton, Ontario L8S 4L7, Canada
| | - Edson P. Bellido
- Department of Materials Science and Engineering, McMaster University, 1280 Main Street W., Hamilton, Ontario L8S 4L7, Canada
| | - Leyla Soleymani
- Department of Engineering Physics, McMaster University, 1280 Main Street W., Hamilton, Ontario L8S 4K1, Canada
- School of Biomedical Engineering, McMaster University, 1280 Main Street W., Hamilton, Ontario L8S 4K1, Canada
| | - Gianluigi A. Botton
- Department of Materials Science and Engineering, McMaster University, 1280 Main Street W., Hamilton, Ontario L8S 4L7, Canada
- Canadian Light Source, 44 Innovation Boulevard, Saskatoon, Saskatchewan S7N 2V3, Canada
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16
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Zeng Y, Madsen SJ, Yankovich AB, Olsson E, Sinclair R. Comparative electron and photon excitation of localized surface plasmon resonance in lithographic gold arrays for enhanced Raman scattering. NANOSCALE 2020; 12:23768-23779. [PMID: 33232431 DOI: 10.1039/d0nr04081a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The ability to tune the localized surface plasmon resonance (LSPR) of nanostructures is desirable for surface enhanced Raman spectroscopy (SERS), plasmon-assisted chemistry and other nanophotonic applications. Although historically the LSPR is mainly studied by optical techniques, with the recent advancement in electron monochromators and correctors, it has attracted considerable attention in transmission electron microscopy (TEM). Here, we use electron energy loss spectroscopy (EELS) in a scanning TEM to study individual gold nanodiscs and bowties in lithographic arrays with variable LSPRs by adjusting the size, interspacing, shape and dielectric environment during the nanofabrication process. We observe the strongest Raman signal enhancement when the LSPR frequency is close to the incident laser frequency in Raman spectroscopy. A simplified harmonic oscillator model is used to estimate SERS enhancement factor (EF) from EELS, bridging the connection between electron and photon excitation of plasmonic arrays. This work demonstrates that STEM-EELS shows promise for revealing the contributions of specific LSPR modes to SERS EF. Our results provide guidelines to fine-tune nanoparticle parameters to deliver the maximum signal enhancement in biosensing applications, such as early cancer detection.
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Affiliation(s)
- Yitian Zeng
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
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17
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Downing CA, Weick G. Plasmonic modes in cylindrical nanoparticles and dimers. Proc Math Phys Eng Sci 2020; 476:20200530. [PMID: 33408559 PMCID: PMC7776974 DOI: 10.1098/rspa.2020.0530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 11/16/2020] [Indexed: 11/12/2022] Open
Abstract
We present analytical expressions for the resonance frequencies of the plasmonic modes hosted in a cylindrical nanoparticle within the quasi-static approximation. Our theoretical model gives us access to both the longitudinally and transversally polarized dipolar modes for a metallic cylinder with an arbitrary aspect ratio, which allows us to capture the physics of both plasmonic nanodisks and nanowires. We also calculate quantum mechanical corrections to these resonance frequencies due to the spill-out effect, which is of relevance for cylinders with nanometric dimensions. We go on to consider the coupling of localized surface plasmons in a dimer of cylindrical nanoparticles, which leads to collective plasmonic excitations. We extend our theoretical formalism to construct an analytical model of the dimer, describing the evolution with the inter-nanoparticle separation of the resultant bright and dark collective modes. We comment on the renormalization of the coupled mode frequencies due to the spill-out effect, and discuss some methods of experimental detection.
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Affiliation(s)
- Charles A. Downing
- Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Department of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, UK
| | - Guillaume Weick
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 67000 Strasbourg, France
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18
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Rahman AU, Geng J, Rehman SU, Iqbal MJ, Jin R. Interface-Induced Near-Infrared Response of Gold-Silica Hybrid Nanoparticles Antennas. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1996. [PMID: 33050365 PMCID: PMC7650551 DOI: 10.3390/nano10101996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/11/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
We proposed an IR absorber hybrid nanoantenna comprise of two overlapping gold nanoparticles residing over larger a silica nanoparticle. A wet chemical route was employed to prepare the hybrid structure of nanoantenna. High-resolution transmission electron microscope was used to measure the size and morphology of the nanoantenna. The Hybrid nanoantenna was excited by electron beam to investigate the optical response over a large wavelength range using Electron Energy Loss Spectroscopy. The beam of the electron was focused and we measured the electron energy loss spectra at different point of interest, which confirmed the of Low Energy Surface Plasmon Politron resonances in the IR region. The optical response of the nanoantenna was simulated numerically by employing Electric Hertzian dipole using finite element method with frequency domain solver in CST Microwave Studio. We used the Electric Hertzian dipole approach for the first time to model the Electron Energy Loss Spectroscopy experiment. The Electron Energy Loss Spectroscopy experimental results with their numerically simulated values confirmed the plasmonic resonance at the interface of the two overlapped gold nanoparticles.
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Affiliation(s)
- Atta Ur Rahman
- Electronic Engineering Department, Shanghai Jiao Tong University, Shanghai 200240, China; (A.U.R.); (S.U.R.); (R.J.)
- School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Junping Geng
- Electronic Engineering Department, Shanghai Jiao Tong University, Shanghai 200240, China; (A.U.R.); (S.U.R.); (R.J.)
| | - Sami Ur Rehman
- Electronic Engineering Department, Shanghai Jiao Tong University, Shanghai 200240, China; (A.U.R.); (S.U.R.); (R.J.)
| | | | - Ronghong Jin
- Electronic Engineering Department, Shanghai Jiao Tong University, Shanghai 200240, China; (A.U.R.); (S.U.R.); (R.J.)
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19
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Bhanushali S, Mahasivam S, Ramanathan R, Singh M, Harrop Mayes EL, Murdoch BJ, Bansal V, Sastry M. Photomodulated Spatially Confined Chemical Reactivity in a Single Silver Nanoprism. ACS NANO 2020; 14:11100-11109. [PMID: 32790283 DOI: 10.1021/acsnano.0c00966] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Single-atom and single-particle catalysis is an area of considerable topical interest due to their potential in explaining important fundamental processes and applications across several areas. An interesting avenue in single-particle catalysis is spatial control of chemical reactivity within the particle by employing light as an external stimulus. To demonstrate this concept, we report galvanic replacement reactions (GRRs) as a spatial marker of subparticle chemical reactivity of a silver nanoprism with AuCl4- ions under optical excitation. The location of a GRR within a single Ag nanoprism can be spatially controlled depending on the plasmon mode excited. This leads to chemomorphological transformation of Ag nanoprisms into interesting Ag-Au structures. This spatial biasing effect is attributed to localized hot electron injection from the tips and edges of the silver nanoprisms to the adjacent reactants that correlate with excitation of different surface plasmon modes. The study also employs low-energy-loss EELS mapping to additionally probe the spatially confined redox reaction within a silver nanoprism. The findings presented here allow the visualization of a plasmon-driven subparticle chemical transformation with high resolution. The selective optical excitation of surface plasmon eigenmodes of anisotropic nanoparticles offers opportunities to spatially modulate chemical transformations mediated by hot electron transfer.
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Affiliation(s)
- Sushrut Bhanushali
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia
| | - Sanje Mahasivam
- Ian Potter NanoBioSensing Facility, NanoBiotechnology Research Laboratory, School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Rajesh Ramanathan
- Ian Potter NanoBioSensing Facility, NanoBiotechnology Research Laboratory, School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Mandeep Singh
- Ian Potter NanoBioSensing Facility, NanoBiotechnology Research Laboratory, School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Edwin Lawrence Harrop Mayes
- RMIT Microscopy and Microanalysis Facility, College of Science, Engineering & Health, RMIT University, Melbourne, Victoria 3001, Australia
| | - Billy James Murdoch
- RMIT Microscopy and Microanalysis Facility, College of Science, Engineering & Health, RMIT University, Melbourne, Victoria 3001, Australia
| | - Vipul Bansal
- Ian Potter NanoBioSensing Facility, NanoBiotechnology Research Laboratory, School of Science, RMIT University, Melbourne, Victoria 3001, Australia
| | - Murali Sastry
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia
- IITB-Monash Research Academy, Indian Institute of Technology Bombay, Mumbai 400076, India
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20
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Yang Y, Hobbs RG, Keathley PD, Berggren KK. Electron energy loss of ultraviolet plasmonic modes in aluminum nanodisks. OPTICS EXPRESS 2020; 28:27405-27414. [PMID: 32988035 DOI: 10.1364/oe.401835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 08/16/2020] [Indexed: 06/11/2023]
Abstract
We theoretically investigated electron energy loss spectroscopy (EELS) of ultraviolet surface plasmon modes in aluminum nanodisks. Using full-wave Maxell electromagnetic simulations, we studied the impact of the diameter on the resonant modes of the nanodisks. We found that the mode behavior can be separately classified for two distinct cases: (1) flat nanodisks where the diameter is much larger than the thickness and (2) thick nanodisks where the diameter is comparable to the thickness. While the multipolar edge modes and breathing modes of flat nanostructures have previously been interpreted using intuitive, analytical models based on surface plasmon polariton (SPP) modes of a thin-film stack, it has been found that the true dispersion relation of the multipolar edge modes deviates significantly from the SPP dispersion relation. Here, we developed a modified intuitive model that uses effective wavelength theory to accurately model this dispersion relation with significantly less computational overhead compared to full-wave Maxwell electromagnetic simulations. However, for the case of thick nanodisks, this effective wavelength theory breaks down, and such intuitive models are no longer viable. We found that this is because some modes of the thick nanodisks carry a polar (i.e., out of the substrate plane or along the electron beam direction) dependence and cannot be simply categorized as radial breathing modes or angular (azimuthal) multipolar edge modes. This polar dependence leads to radiative losses, motivating the use of simultaneous EELS and cathodoluminescence measurements when experimentally investigating the complex mode behavior of thick nanostructures.
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21
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Karanikolas V. Entanglement of quantum emitters interacting through an ultra-thin noble metal nanodisk. OPTICS EXPRESS 2020; 28:24171-24184. [PMID: 32752401 DOI: 10.1364/oe.396268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/12/2020] [Indexed: 06/11/2023]
Abstract
Ultra-thin metallic nanodisks, supporting localized plasmon (LP) modes, are used as a platform to facilitate high entanglement between distant quantum emitters (QEs). High Purcell factors, with values above 103, are probed for a QE placed near to an ultra-thin metallic nanodisk, composed of the noble metals Au, Ag, Al, and Cu. The disk supports two sets of localized plasmon modes, which can be excited by QEs with different transition dipole moment orientations. The two QEs are placed on opposite sides of the nanodisk, and their concurrence is used as a measure of the entanglement. We observe that the pair of QEs remains entangled for a duration that surpasses the relaxation time of the individual QE interacting with the metallic disk. Simultaneously, the QEs reach the entangled steady state faster than in the case where the QEs are in free space. Our results reveal a high concurrence value for a QES separation distance of 60 nm, and a transition energy of 0.8 eV (λ = 1550 nm). The robustness exhibited by this system under study paves the way for future quantum applications.
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22
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Ringe E. Shapes, Plasmonic Properties, and Reactivity of Magnesium Nanoparticles. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2020; 124:15665-15679. [PMID: 32905178 PMCID: PMC7467285 DOI: 10.1021/acs.jpcc.0c03871] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/10/2020] [Indexed: 05/19/2023]
Abstract
Localized surface plasmon resonances have attracted much attention due to their ability to enhance light-matter interactions and manipulate light at the subwavelength level. Recently, alternatives to the rare and expensive noble metals Ag and Au have been sought for more sustainable and large-scale plasmonic utilization. Mg supports plasmon resonances, is one of the most abundant elements in earth's crust, and is fully biocompatible, making it an attractive framework for plasmonics. This feature article first reports the hexagonal, folded, and kite-like shapes expected theoretically from a modified Wulff construction for single crystal and twinned Mg structures and describes their excellent match with experimental results. Then, the optical response of Mg nanoparticles is overviewed, highlighting Mg's ability to sustain localized surface plasmon resonances across the ultraviolet, visible, and near-infrared electromagnetic ranges. The various resonant modes of hexagons, leading to the highly localized electric field characteristic of plasmonic behavior, are presented numerically and experimentally. The evolution of these modes and the associated field from hexagons to the lower symmetry folded structures is then probed, again by matching simulations, optical, and electron spectroscopy data. Lastly, results demonstrating the opportunities and challenges related to the high chemical reactivity of Mg are discussed, including surface oxide formation and galvanic replacement as a synthetic tool for bimetallics. This Feature Article concludes with a summary of the next steps, open questions, and future directions in the field of Mg nanoplasmonics.
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Affiliation(s)
- Emilie Ringe
- Department of Materials Science
and Metallurgy, Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom CB2 3EQ
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23
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Near-field transmission matrix microscopy for mapping high-order eigenmodes of subwavelength nanostructures. Nat Commun 2020; 11:2575. [PMID: 32444615 PMCID: PMC7244505 DOI: 10.1038/s41467-020-16263-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 04/21/2020] [Indexed: 01/27/2023] Open
Abstract
As nanoscale photonic devices are densely integrated, multiple near-field optical eigenmodes take part in their functionalization. Inevitably, these eigenmodes are highly multiplexed in their spectra and superposed in their spatial distributions, making it extremely difficult for conventional near-field scanning optical microscopy (NSOM) to address individual eigenmodes. Here, we develop a near-field transmission matrix microscopy for mapping the high-order eigenmodes of nanostructures, which are invisible with conventional NSOM. At an excitation wavelength where multiple modes are superposed, we measure the near-field amplitude and phase maps for various far-field illumination angles, from which we construct a fully phase-referenced far- to near-field transmission matrix. By performing the singular value decomposition, we extract orthogonal near-field eigenmodes such as anti-symmetric mode and quadruple mode of multiple nano-slits whose gap size (50 nm) is smaller than the probe aperture (150 nm). Analytic model and numerical mode analysis validated the experimentally observed modes. Nanoscale integrated photonic devices have complicated combinations of optical eigenmodes. Here, the authors develop a far- to near-field transmission matrix microscopy that enables measuring higher-order modes of nanostructures beyond the capabilities of conventional near-field microscopy.
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24
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Fiedler S, Raza S, Ai R, Wang J, Busch K, Stenger N, Mortensen NA, Wolff C. Importance of substrates for the visibility of "dark" plasmonic modes. OPTICS EXPRESS 2020; 28:13938-13948. [PMID: 32403859 DOI: 10.1364/oe.393056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Dark plasmonic modes have interesting properties, including longer lifetimes and narrower linewidths than their radiative counterpart, and little to no radiative losses. However, they have not been extensively studied yet due to their optical inaccessibility. In this work, we systematically investigated the dark radial breathing modes (RBMs) in monocrystalline gold nanodisks, specifically their outcoupling behavior into the far-field by cathodoluminescence spectroscopy. Increasing the substrate thickness resulted in an up to 4-fold enhanced visibility. This is attributed to breaking the mirror symmetry by the high-index substrate, creating an effective dipole moment. Furthermore, the resonance energy of the dark RMBs can be easily tuned by varying the nanodisk diameter, making them promising candidates for nanophotonic applications.
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25
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Goetz S, Bauch M, Dimopoulos T, Trassl S. Ultrathin sputter-deposited plasmonic silver nanostructures. NANOSCALE ADVANCES 2020; 2:869-877. [PMID: 36133228 PMCID: PMC9418784 DOI: 10.1039/c9na00762h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/13/2020] [Indexed: 06/11/2023]
Abstract
In this study, ultrathin silver plasmonic nanostructures are fabricated by sputter deposition on substrates patterned by nanoimprint lithography, without additional lift-off processes. Detailed investigation of silver growth on different substrates results in a structured, defect-free silver film with thickness down to 6 nm, deposited on a thin layer of doped zinc oxide. Variation of the aspect ratio of the nanostructure reduces grain formation at the flanks, allowing for well-separated disk and hole arrays, even though conventional magnetron sputtering is less directional than evaporation. The resulting disk-hole array features high average transmittance in the visible range of 71% and a strong plasmonic dipole resonance in the near-infrared region. It is shown that the ultrathin Ag film exhibits even lower optical losses in the NIR range compared to known bulk optical properties. The presented FDTD simulations agree well with experimental spectra and show that for defect-free, ultrathin Ag nanostructures, bulk optical properties of Ag are sufficient for a reliable simulation-based design.
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Affiliation(s)
- Selina Goetz
- AIT Austrian Institute of Technology, Center for Energy, Photovoltaic Systems Giefinggasse 4 1210 Vienna Austria
| | - Martin Bauch
- AIT Austrian Institute of Technology, Center for Energy, Photovoltaic Systems Giefinggasse 4 1210 Vienna Austria
| | - Theodoros Dimopoulos
- AIT Austrian Institute of Technology, Center for Energy, Photovoltaic Systems Giefinggasse 4 1210 Vienna Austria
| | - Stephan Trassl
- HUECK FOLIEN GmbH Gewerbepark 30 4342 Baumgartenberg Austria
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26
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Li L, Wang L, Du C, Guan Z, Xiang Y, Wu W, Ren M, Zhang X, Tang A, Cai W, Xu J. Ultrastrong coupling of CdZnS/ZnS quantum dots to bonding breathing plasmons of aluminum metal-insulator-metal nanocavities in near-ultraviolet spectrum. NANOSCALE 2020; 12:3112-3120. [PMID: 31965128 DOI: 10.1039/c9nr08048a] [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
Strong coupling originating from excitons of quantum dots and plasmons in nanocavities can be realized at room temperature due to the large electromagnetic field enhancement of plasmons, offering building blocks for quantum information systems, ultralow-power switches and lasers. However, most of the current strong coupling effects were realized by the interaction between excitons and far-field light excited bright plasmon modes in the visible range. Beyond that, there is still a lack of direct imaging of polariton modes at the nanoscale. In this work, by using cathodoluminescence, ultrastrong coupling with Rabi splitting exceeding 1 eV between bonding breathing plasmons of aluminum (Al) metal-insulator-metal (MIM) cavities and excited states of CdZnS/ZnS quantum dots was observed in the near-ultraviolet (UV) spectrum. Further, the hybridization of the QDs excitons and bonding breathing plasmonic modes is verified by deep-subwavelength images of polaritonic modes in real-space. Analytic analysis based on the coupled oscillator model and full-wave electromagnetic simulations is consistent with our experimental results. Our work not only indicates the great potential of electron excited plasmon modes for strong coupling applications, but also extends the polaritonic frequency to the UV range with Al nanocavities.
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Affiliation(s)
- Li Li
- The Key Laboratory of Weak-Light Nonlinear Photonics, Ministry of Education, School of Physics and TEDA Applied Physics Institute, Nankai University, Tianjin 300457, China.
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27
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Cho SH, Roccapriore KM, Dass CK, Ghosh S, Choi J, Noh J, Reimnitz LC, Heo S, Kim K, Xie K, Korgel BA, Li X, Hendrickson JR, Hachtel JA, Milliron DJ. Spectrally tunable infrared plasmonic F,Sn:In 2O 3 nanocrystal cubes. J Chem Phys 2020; 152:014709. [PMID: 31914766 DOI: 10.1063/1.5139050] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A synthetic challenge in faceted metal oxide nanocrystals (NCs) is realizing tunable localized surface plasmon resonance (LSPR) near-field response in the infrared (IR). Cube-shaped nanoparticles of noble metals exhibit LSPR spectral tunability limited to visible spectral range. Here, we describe the colloidal synthesis of fluorine, tin codoped indium oxide (F,Sn:In2O3) NC cubes with tunable IR range LSPR for around 10 nm particle sizes. Free carrier concentration is tuned through controlled Sn dopant incorporation, where Sn is an aliovalent n-type dopant in the In2O3 lattice. F shapes the NC morphology into cubes by functioning as a surfactant on the {100} crystallographic facets. Cube shaped F,Sn:In2O3 NCs exhibit narrow, shape-dependent multimodal LSPR due to corner, edge, and face centered modes. Monolayer NC arrays are fabricated through a liquid-air interface assembly, further demonstrating tunable LSPR response as NC film nanocavities that can heighten near-field enhancement (NFE). The tunable F,Sn:In2O3 NC near-field is coupled with PbS quantum dots, via the Purcell effect. The detuning frequency between the nanocavity and exciton is varied, resulting in IR near-field dependent enhanced exciton lifetime decay. LSPR near-field tunability is directly visualized through IR range scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS). STEM-EELS mapping of the spatially confined near-field in the F,Sn:In2O3 NC array interparticle gap demonstrates elevated NFE tunability in the arrays.
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Affiliation(s)
- Shin Hum Cho
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Kevin M Roccapriore
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Chandriker Kavir Dass
- Sensors Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Dayton, Ohio 45433, USA
| | - Sandeep Ghosh
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Junho Choi
- Department of Physics, Center for Complex Quantum Systems, The University of Texas, Austin, Texas 78712, USA
| | - Jungchul Noh
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Lauren C Reimnitz
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Sungyeon Heo
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Kihoon Kim
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Karen Xie
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Brian A Korgel
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Xiaoqin Li
- Department of Physics, Center for Complex Quantum Systems, The University of Texas, Austin, Texas 78712, USA
| | - Joshua R Hendrickson
- Sensors Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Dayton, Ohio 45433, USA
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Delia J Milliron
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA
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Unprecedented efficient electron transport across Au nanoparticles with up to 25-nm insulating SiO 2-shells. Sci Rep 2019; 9:18336. [PMID: 31797902 PMCID: PMC6892908 DOI: 10.1038/s41598-019-54835-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 11/11/2019] [Indexed: 01/04/2023] Open
Abstract
Quantum tunneling is the basis of molecular electronics, but often its electron transport range is too short to overcome technical defects caused by downscaling of electronic devices, which limits the development of molecular-/nano-electronics. Marrying electronics with plasmonics may well present a revolutionary way to meet this challenge as it can manipulate electron flow with plasmonics at the nanoscale. Here we report on unusually efficient temperature-independent electron transport, with some photoconductivity, across a new type of junction with active plasmonics. The junction is made by assembly of SiO2 shell-insulated Au nanoparticles (Au@SiO2 NPs) into dense nanomembranes of a few Au@SiO2 layers thick and transport is measured across these membranes. We propose that the mechanism is plasmon-enabled transport, possibly tunneling (as it is temperature-independent). Unprecedentedly ultra-long-range transport across one, up to even three layers of Au@SiO2 in the junction, with a cumulative insulating (silica) gap up to 29 nm/NP layer was achieved, well beyond the measurable limit for normal quantum mechanical tunneling across insulators (~2.5 nm at 0.5–1 V). This finding opens up a new interdisciplinary field of exploration in nanoelectronics with wide potential impact on such areas as electronic information transfer.
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29
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Xiao F, Cao S, Shang W, Zhu W, Han L, Mei T, Premaratne M, Zhao J. Enhanced second-harmonic generation assisted by breathing mode in a multi-resonant plasmonic trimer. OPTICS LETTERS 2019; 44:3813-3816. [PMID: 31368979 DOI: 10.1364/ol.44.003813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 06/28/2019] [Indexed: 06/10/2023]
Abstract
Boosting the nonlinear conversion rate in nanoscale is pivotal for practical applications such as highly sensitive biosensors, extreme ultra-violate light sources, and frequency combs. Here, we theoretically study the enhancement of second-harmonic generation (SHG) in a plasmonic trimer assisted by breathing modes. The geometry of the trimer is fine-tuned to produce strong plasmonic resonances at both the fundamental and SH wavelengths to boost SHG intensity. Moreover, it is found that breathing modes show remarkable ability to augment SHG by increasing the enhancement area. In particular, these breathing modes ensure a substantial spatial mode overlap at the fundamental and SH wavelengths, resulting in further promotion of the SHG conversation rate. We envision that our findings could enable applications in nanoscale frequency converters with high efficiency.
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30
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Chatterjee S, Ricciardi L, Deitz JI, Williams REA, McComb DW, Strangi G. Manipulating acoustic and plasmonic modes in gold nanostars. NANOSCALE ADVANCES 2019; 1:2690-2698. [PMID: 36132721 PMCID: PMC9418612 DOI: 10.1039/c9na00301k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 05/27/2019] [Indexed: 06/16/2023]
Abstract
In this contribution experimental evidence of plasmonic edge modes and acoustic breathing modes in gold nanostars (AuNSs) is reported. AuNSs are synthesized by a surfactant-free, one-step wet-chemistry method. Optical extinction measurements of AuNSs confirm the presence of localized surface plasmon resonances (LSPRs), while electron energy-loss spectroscopy (EELS) using a scanning transmission electron microscope (STEM) shows the spatial distribution of LSPRs and reveals the presence of acoustic breathing modes. Plasmonic hot-spots generated at the pinnacle of the sharp spikes, due to the optically active dipolar edge mode, allow significant intensity enhancement of local fields and hot-electron injection, and are thus useful for size detection of small protein molecules. The breathing modes observed away from the apices of the nanostars are identified as stimulated dark modes - they have an acoustic nature - and likely originate from the confinement of the surface plasmon by the geometrical boundaries of a nanostructure. The presence of both types of modes is verified by numerical simulations. Both these modes offer the possibility of designing nanoplasmonic antennas based on AuNSs, which can provide information on both mass and polarizability of biomolecules using a two-step molecular detection process.
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Affiliation(s)
- Sharmistha Chatterjee
- Department of Physics, Case Western Reserve University 10600 Euclid Avenue Cleveland OH 44106 USA
- CNR-NANOTEC Istituto di Nanotecnologia, Department of Physics, University of Calabria 87036-Rende Italy
- Fondazione con Il Cuore Via Roma 170 88811 Cirò Marina Italy
| | - Loredana Ricciardi
- CNR-NANOTEC Istituto di Nanotecnologia, Department of Physics, University of Calabria 87036-Rende Italy
- Fondazione con Il Cuore Via Roma 170 88811 Cirò Marina Italy
| | - Julia I Deitz
- Center for Electron Microscopy and Analysis, The Ohio State University Columbus OH 43212 USA
- Department of Material Science and Engineering, The Ohio State University Columbus OH 43210 USA
| | - Robert E A Williams
- Center for Electron Microscopy and Analysis, The Ohio State University Columbus OH 43212 USA
| | - David W McComb
- Center for Electron Microscopy and Analysis, The Ohio State University Columbus OH 43212 USA
- Department of Material Science and Engineering, The Ohio State University Columbus OH 43210 USA
| | - Giuseppe Strangi
- Department of Physics, Case Western Reserve University 10600 Euclid Avenue Cleveland OH 44106 USA
- CNR-NANOTEC Istituto di Nanotecnologia, Department of Physics, University of Calabria 87036-Rende Italy
- Fondazione con Il Cuore Via Roma 170 88811 Cirò Marina Italy
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31
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Bauch M, Dimopoulos T, Trassl S. Nanostructured, ultrathin silver-based transparent electrode with broadband near-infrared plasmonic resonance. NANOTECHNOLOGY 2019; 30:265201. [PMID: 30840928 DOI: 10.1088/1361-6528/ab0d39] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A nanostructured transparent electrode with high average visible transmittance of 76%, low sheet resistance of 7.0 Ω/sq and steep transmittance drop in the near-infrared (NIR) range is investigated by simulations and experiments. The electrode is composed of a nanostructured substrate, on which a trilayer, consisting of an ultrathin 14 nm thick silver film embedded between thin films of TiO2 and Al-doped ZnO, is deposited. Directional silver deposition results in the formation of a disk-hole array without additional lift-off or etching steps. While the trilayer approach enables increased visible transmittance, the transmittance in the NIR regime is decreased by a broadband plasmonic dipole excitation in the disk-hole array. Moreover, a rich mode spectrum of weaker multipole surface plasmon excitations is observed in the nanodisk- and nanohole array. The presented electrode holds great potential for applications in optoelectronic devices, solar control coatings and solar cells.
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Affiliation(s)
- Martin Bauch
- Photovoltaic Systems, AIT-Austrian Institute of Technology, Giefinggasse 4, A-1210 Vienna, Austria
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32
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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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33
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Zhang Q, Liu Z, Qin F, Zeng SJ, Zhang D, Gu Z, Liu X, Xiao JJ. Exploring optical resonances of nanoparticles excited by optical Skyrmion lattices. OPTICS EXPRESS 2019; 27:7009-7022. [PMID: 30876274 DOI: 10.1364/oe.27.007009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 02/18/2019] [Indexed: 06/09/2023]
Abstract
Recently, optical Skyrmion lattices (OSLs) have been realized in evanescent electromagnetic fields. OSLs possess topologically stable field configurations, which promise many optics and photonics applications. Here, we demonstrate that OSLs can serve as versatile structured optical near-fields to assist with studies of a variety of photonic modes in nanoparticles. We firstly show that OSL is capable of selectively exciting electric and magnetic multipole modes by placing a nanoparticle at different positions in the lattice. We then disclose that OSLs can efficiently excite some intriguing resonant modes, including toroidal and plasmonic dark modes, in dielectric or metal nanoparticles. Our results may enhance understanding of the interaction between OSLs and nanoparticles and find applications associated with precise control over resonant modes in nanostructures.
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34
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Matsuura T, Imaeda K, Hasegawa S, Suzuki H, Imura K. Characterization of Overlapped Plasmon Modes in a Gold Hexagonal Plate Revealed by Three-Dimensional Near-Field Optical Microscopy. J Phys Chem Lett 2019; 10:819-824. [PMID: 30735394 DOI: 10.1021/acs.jpclett.8b03578] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
A detailed characterization of plasmon modes is important not only for a deeper understanding of plasmons but also for their practical applications. In this study, we investigated the three-dimensional near-field characteristics of high-order plasmon modes excited in a gold hexagonal nanoplate. From the near-field spectroscopic images, we found that both in-plane and out-of-plane plasmon modes observed near 900 nm were spectrally and spatially overlapped. We performed three-dimensional near-field measurement to reveal the optical characteristics of the overlapped modes in detail. We found that the steric near-field distribution near the nanoplate strongly depended on the plasmon mode, and the out-of-plane mode confines electromagnetic fields more tightly than the in-plane mode. We also found that the in-plane mode was dominantly visualized as the probe tip-sample distance increased. These findings demonstrate that the three-dimensional near-field technique enables selective visualization of a single plasmon mode even if multiple modes are spatially and spectrally overlapped.
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Affiliation(s)
- Takuya Matsuura
- Department of Chemistry and Biochemistry, School of Advanced Science and Engineering , Waseda University , Shinjuku , Tokyo 169-8555 , Japan
| | - Keisuke Imaeda
- Research Institute for Science and Engineering , Waseda University , Shinjuku , Tokyo 169-8555 , Japan
| | - Seiju Hasegawa
- Department of Chemistry and Biochemistry, School of Advanced Science and Engineering , Waseda University , Shinjuku , Tokyo 169-8555 , Japan
| | - Hiromasa Suzuki
- Department of Chemistry and Biochemistry, School of Advanced Science and Engineering , Waseda University , Shinjuku , Tokyo 169-8555 , Japan
| | - Kohei Imura
- Department of Chemistry and Biochemistry, School of Advanced Science and Engineering , Waseda University , Shinjuku , Tokyo 169-8555 , Japan
- Research Institute for Science and Engineering , Waseda University , Shinjuku , Tokyo 169-8555 , Japan
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35
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Xiao F, Wang G, Shang W, Zhu W, Han L, Mei T, Premaratne M, Zhao J. Radial breathing modes coupling in plasmonic molecules. OPTICS EXPRESS 2019; 27:5116-5124. [PMID: 30876114 DOI: 10.1364/oe.27.005116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/31/2019] [Indexed: 06/09/2023]
Abstract
Metallic hexamer, very much the plasmonic analog of benzene molecule, provides an ideal platform to mimic modes coupling and hybridization in molecular systems. To demonstrate this, we present a detailed study on radial breathing mode (RBM) coupling in a plasmonic dual-hexamers. We excite RBMs of hexamers by symmetrically matching the polarization state of the illumination with the distribution of electric dipole moments of the dual-hexamer. It is found that the RBM coupling exhibits a nonexponential decay when the inter-hexamer separation is increased, owing to the dark mode nature of RBM. When the outer hexamer is subjected to the in-plane twisting, resonant wavelengths of two coupled RBMs as well as the coupling constant show cosine variations with the twist angle, indicating the symmetry of hexamer structure plays a critical role in the coupling of RBMs. Moreover, it is demonstrated that the coupling of RBMs is dominated by the in-plane interaction as the outer hexamer is under an out-of-plane tilting, causing convergence of resonant wavelengths of the two coupled RBMs with increasing tilt angle. Our results not only provide an insight into the plasmonic RBM coupling mechanism, but also pave the way to systematically control the spectral response of plasmonic molecules.
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36
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Schaffernak G, Krug MK, Belitsch M, Gašparić M, Ditlbacher H, Hohenester U, Krenn JR, Hohenau A. Plasmonic Dispersion Relations and Intensity Enhancement of Metal-Insulator-Metal Nanodisks. ACS PHOTONICS 2018; 5:4823-4827. [PMID: 30591924 PMCID: PMC6302311 DOI: 10.1021/acsphotonics.8b00938] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Indexed: 05/15/2023]
Abstract
We show that the plasmon modes of vertically stacked Ag-SiO2-Ag nanodisks can be understood and classified as hybridized surface and edge modes. We describe their universal dispersion relations and demonstrate that coupling-induced spectral shifts are significantly stronger for surface modes than for edge modes. The experimental data correspond well to numerical simulations. In addition, we estimate optical intensity enhancements of the stacked nanodisks in the range of 1000.
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37
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Mayevsky AD, Davis TJ, Ballard PM, Henderson CA, Funston AM. Mesoscale surface plasmons: modelling and imaging using near-field scanning optical microscopy. OPTICS EXPRESS 2018; 26:23426-23435. [PMID: 30184843 DOI: 10.1364/oe.26.023426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 08/09/2018] [Indexed: 06/08/2023]
Abstract
Meso-scale plasmons are supported by structures with dimensions on the order of tens of plasmon wavelengths. Metal structures at this length-scale are promising for the design and engineering of structures to direct the flow of optical energy and generate high intensity, localized electric fields. The near-field optical properties of mesoscale crystalline gold plates were examined using near-field scanning optical microscopy with a focus on the effects of modifying morphology and excitation conditions. Excitation of surface plasmon polaritons (SPPs) at plate edges and their subsequent propagation and interference as radial waves across the surface results in nodes of enhancement of the near-field on the plate surface at specific positions within the plate. The spatial position of the near-field enhancement may be directed by controlling either, or both, the boundary conditions (plate shape) and polarization of the excitation light.
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38
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El-Demellawi JK, Lopatin S, Yin J, Mohammed OF, Alshareef HN. Tunable Multipolar Surface Plasmons in 2D Ti 3C 2 T x MXene Flakes. ACS NANO 2018; 12:8485-8493. [PMID: 30020767 DOI: 10.1021/acsnano.8b04029] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
2D Ti3C2 T x MXenes were recently shown to exhibit intense surface plasmon (SP) excitations; however, their spatial variation over individual Ti3C2 T x flakes remains undiscovered. Here, we use scanning transmission electron microscopy (STEM) combined with ultra-high-resolution electron energy loss spectroscopy (EELS) to investigate the spatial and energy distribution of SPs (both optically active and forbidden modes) in mono- and multilayered Ti3C2 T x flakes. With STEM-EELS mapping, the inherent interband transition in addition to a variety of transversal and longitudinal SP modes (ranging from visible down to 0.1 eV in MIR) are directly visualized and correlated with the shape, size, and thickness of Ti3C2 T x flakes. The independent polarizability of Ti3C2 T x monolayers is unambiguously demonstrated and attributed to their unusual weak interlayer coupling. This characteristic allows for engineering a class of nanoscale systems, where each monolayer in the multilayered structure of Ti3C2 T x has its own set of SPs with distinctive multipolar characters. Moreover, the tunability of the SP energies is highlighted by conducting in situ heating STEM to monitor the change of the surface functionalization of Ti3C2 T x through annealing at temperatures up to 900 °C. At temperatures above 500 °C, the observed fluorine (F) desorption multiplies the metal-like free electron density of Ti3C2 T x flakes, resulting in a monotonic blue-shift in the SP energy of all modes. These results underline the great potential for the development of Ti3C2 T x-based applications, spanning the visible-MIR spectrum, relying on the excitation and detection of single SPs.
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Affiliation(s)
- Jehad K El-Demellawi
- Physical Sciences and Engineering Division , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Kingdom of Saudi Arabia
- KAUST Solar Center (KSC) , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Kingdom of Saudi Arabia
| | - Sergei Lopatin
- Core Laboratories , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Kingdom of Saudi Arabia
| | - Jun Yin
- KAUST Solar Center (KSC) , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Kingdom of Saudi Arabia
| | - Omar F Mohammed
- KAUST Solar Center (KSC) , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Kingdom of Saudi Arabia
| | - Husam N Alshareef
- Physical Sciences and Engineering Division , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Kingdom of Saudi Arabia
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39
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Lee S, Park Y, Kim J, Roh YG, Park QH. Selective bright and dark mode excitation in coupled nanoantennas. OPTICS EXPRESS 2018; 26:21537-21545. [PMID: 30130860 DOI: 10.1364/oe.26.021537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/23/2018] [Indexed: 06/08/2023]
Abstract
Coupled nanoantennas as metamaterial unit elements possess peculiar spectral and radiational behaviors. We show that nanoantennas made of two identical plasmonic slot resonators can greatly enhance the quality factors of resonance spectra and control radiation patterns through the selective excitation of bright and dark coupled modes. We confirm experimentally the enhanced quality factor of a bright mode in coupled nanoantennas. Adding phase modulators to the coupled microwave antennas, we demonstrate the "dark mode only" excitation of coupled microwave antennas with an incident plane wave. We also show that the bright-to-dark mode conversion and the related changes in radiation patterns can be controlled by the polarization of incident waves. In particular, we achieve leftward or rightward uni-directional radiation upon the injection of left or right circularly polarized waves.
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40
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Imaeda K, Hasegawa S, Imura K. Static and Dynamic Near-Field Measurements of High-Order Plasmon Modes Induced in a Gold Triangular Nanoplate. J Phys Chem Lett 2018; 9:4075-4081. [PMID: 29985621 DOI: 10.1021/acs.jpclett.8b01671] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Precise understanding of the spatiotemporal characteristics of plasmons is essential for the development of applications of plasmonic nanoparticles. In this study, we investigated the spatiotemporal properties of high-order plasmon modes induced in a gold triangular nanoplate by static and dynamic near-field measurements. The near-field transmission measurements revealed that in-plane and out-of-plane polarized plasmon modes were simultaneously excited and these modes spectroscopically and spatially overlapped. The superposition of these modes was visualized in the near-field two-photon excitation image of the nanoplate. We performed time-resolved autocorrelation measurements on the nanoplate and found that the correlation width was broader than the excitation pulse due to the plasmon dephasing process. From the correlation width map of the nanoplate, we experimentally demonstrated that the out-of-plane plasmon mode exhibits a longer dephasing time than the in-plane plasmon mode. These findings indicate that the out-of-plane mode is desirable for improving the performance of plasmons in various applications.
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41
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Horák M, Bukvišová K, Švarc V, Jaskowiec J, Křápek V, Šikola T. Comparative study of plasmonic antennas fabricated by electron beam and focused ion beam lithography. Sci Rep 2018; 8:9640. [PMID: 29941880 PMCID: PMC6018609 DOI: 10.1038/s41598-018-28037-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 06/14/2018] [Indexed: 11/09/2022] Open
Abstract
We present a comparative study of plasmonic antennas fabricated by electron beam lithography and direct focused ion beam milling. We have investigated optical and structural properties and chemical composition of gold disc-shaped plasmonic antennas on a silicon nitride membrane fabricated by both methods to identify their advantages and disadvantages. Plasmonic antennas were characterized using transmission electron microscopy including electron energy loss spectroscopy and energy dispersive X-ray spectroscopy, and atomic force microscopy. We have found stronger plasmonic response with better field confinement in the antennas fabricated by electron beam lithography, which is attributed to their better structural quality, homogeneous thickness, and only moderate contamination mostly of organic nature. Plasmonic antennas fabricated by focused ion beam lithography feature weaker plasmonic response, lower structural quality with pronounced thickness fluctuations, and strong contamination, both organic and inorganic, including implanted ions from the focused beam. While both techniques are suitable for the fabrication of plasmonic antennas, electron beam lithography shall be prioritized over focused ion beam lithography due to better quality and performance of its products.
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Affiliation(s)
- Michal Horák
- Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 612 00, Brno, Czech Republic.
| | - Kristýna Bukvišová
- Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69, Brno, Czech Republic
| | - Vojtěch Švarc
- 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
| | - Jiří Jaskowiec
- Institute of Physical Engineering, Brno University of Technology, Technická 2, 616 69, Brno, Czech Republic
| | - Vlastimil 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
| | - Tomáš 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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42
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Abstract
Nanoparticles of some metals (Cu/Ag/Au) sustain oscillations of their electron cloud called localized surface plasmon resonances (LSPRs). These resonances can occur at optical frequencies and be driven by light, generating enhanced electric fields and spectacular photon scattering. However, current plasmonic metals are rare, expensive, and have a limited resonant frequency range. Recently, much attention has been focused on earth-abundant Al, but Al nanoparticles cannot resonate in the IR. The earth-abundant Mg nanoparticles reported here surmount this limitation. A colloidal synthesis forms hexagonal nanoplates, reflecting Mg's simple hexagonal lattice. The NPs form a thin self-limiting oxide layer that renders them stable suspended in 2-propanol solution for months and dry in air for at least two week. They sustain LSPRs observable in the far-field by optical scattering spectroscopy. Electron energy loss spectroscopy experiments and simulations reveal multiple size-dependent resonances with energies across the UV, visible, and IR. The symmetry of the modes and their interaction with the underlying substrate are studied using numerical methods. Colloidally synthesized Mg thus offers a route to inexpensive, stable nanoparticles with novel shapes and resonances spanning the entire UV-vis-NIR spectrum, making them a flexible addition to the nanoplasmonics toolbox.
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Affiliation(s)
- John S Biggins
- Department of Engineering , University of Cambridge , Trumpington Street , Cambridge CB2 1PZ , United Kingdom
| | | | - Emilie Ringe
- Department of Materials Science and Metallurgy , University of Cambridge , 27 Charles Babbage Road , Cambridge CB3 0FS , United Kingdom
- Department of Earth Sciences , University of Cambridge , Downing Street , Cambridge CB2 3EQ , United Kingdom
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43
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Konečná A, Neuman T, Aizpurua J, Hillenbrand R. Surface-Enhanced Molecular Electron Energy Loss Spectroscopy. ACS NANO 2018; 12:4775-4786. [PMID: 29641179 DOI: 10.1021/acsnano.8b01481] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM) is becoming an important technique in spatially resolved spectral characterization of optical and vibrational properties of matter at the nanoscale. EELS has played a significant role in understanding localized polaritonic excitations in nanoantennas and also allows for studying molecular excitations in nanoconfined samples. Here we theoretically describe the interaction of a localized electron beam with molecule-covered polaritonic nanoantennas, and propose the concept of surface-enhanced molecular EELS exploiting the electromagnetic coupling between the nanoantenna and the molecular sample. Particularly, we study plasmonic and infrared phononic antennas covered by molecular layers, exhibiting either an excitonic or vibrational response. We demonstrate that EEL spectra of these molecule-antenna coupled systems exhibit Fano-like or strong coupling features, similar to the ones observed in far-field optical and infrared spectroscopy. EELS offers the advantage to acquire spectral information with nanoscale spatial resolution, and importantly, to control the antenna-molecule coupling on demand. Considering ongoing instrumental developments, EELS in STEM shows the potential to become a powerful tool for fundamental studies of molecules that are naturally or intentionally located on nanostructures supporting localized plasmon or phonon polaritons. Surface-enhanced EELS might also enable STEM-EELS applications such as remote- and thus damage-free-sensing of the excitonic and vibrational response of molecules, quantum dots, or 2D materials.
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Affiliation(s)
- Andrea Konečná
- Materials Physics Center, CSIC-UPV/EHU , Donostia-San Sebastián , 20018 , Spain
| | - Tomáš Neuman
- Materials Physics Center, CSIC-UPV/EHU , Donostia-San Sebastián , 20018 , Spain
| | - Javier Aizpurua
- Materials Physics Center, CSIC-UPV/EHU , Donostia-San Sebastián , 20018 , Spain
- Donostia International Physics Center DIPC , Donostia-San Sebastián , 20018 , Spain
| | - Rainer Hillenbrand
- IKERBASQUE, Basque Foundation for Science , Bilbao , 48013 , Spain
- CIC NanoGUNE and UPV/EHU , Donostia-San Sebastián , 20018 , Spain
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44
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Schmidt FP, Losquin A, Hofer F, Hohenau A, Krenn JR, Kociak M. How Dark Are Radial Breathing Modes in Plasmonic Nanodisks? ACS PHOTONICS 2018; 5:861-866. [PMID: 29607350 PMCID: PMC5871341 DOI: 10.1021/acsphotonics.7b01060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 05/06/2023]
Abstract
Due to a vanishing dipole moment, radial breathing modes in small flat plasmonic nanoparticles do not couple to light and have to be probed with a near-field source, as in electron energy loss spectroscopy (EELS). With increasing particle size, retardation gives rise to light coupling, enabling probing breathing modes optically or by cathodoluminescence (CL). Here, we investigate single silver nanodisks with diameters of 150-500 nm by EELS and CL in an electron microscope and quantify the EELS/CL ratio, which corresponds to the ratio of full to radiative damping of the breathing mode. For the investigated diameter range, we find the CL signal to increase by about 1 order of magnitude, in agreement with numerical simulations. Due to reciprocity, our findings corroborate former optical experiments and enable a quantitative understanding of the light coupling of dark plasmonic modes.
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Affiliation(s)
- Franz-Philipp Schmidt
- Institute
of Physics, University of Graz, Graz 8010, Austria
- Institute
for Electron Microscopy and Nanoanalysis, Graz University of Technology, Graz 8010, Austria
- E-mail:
| | - Arthur Losquin
- Department
of Physics, Lund University, Lund 221 00, Sweden
- Laboratoire
Ondes et Matière d’Aquitaine, UMR 5798, CNRS-University of Bordeaux, F-33405 Talence Cedex, France
| | - Ferdinand Hofer
- Institute
for Electron Microscopy and Nanoanalysis, Graz University of Technology, Graz 8010, Austria
| | - Andreas Hohenau
- Institute
of Physics, University of Graz, Graz 8010, Austria
| | | | - Mathieu Kociak
- Laboratoire
de Physique des Solides, CNRS UMR 8502,
Université Paris-Sud, 91405 Orsay, France
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45
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Lagos MJ, Trügler A, Amarasinghe V, Feldman LC, Hohenester U, Batson PE. Excitation of long-wavelength surface optical vibrational modes in films, cubes and film/cube composite system using an atom-sized electron beam. Microscopy (Oxf) 2018; 67:i3-i13. [DOI: 10.1093/jmicro/dfx130] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 12/16/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Maureen J Lagos
- Department of Physics and Astronomy
- Department of Materials and Science Engineering, Rutgers University, Piscataway, NJ 08854, USA
- Institute for Advanced Materials, Devices, and Nanotechnology, Rutgers University, Piscataway, NJ 08854, USA
| | - Andreas Trügler
- Institute of Physics, University of Graz, Universitätsplatz 5, Graz 8010, Austria
| | - Voshadhi Amarasinghe
- Institute for Advanced Materials, Devices, and Nanotechnology, Rutgers University, Piscataway, NJ 08854, USA
| | - Leonard C Feldman
- Department of Physics and Astronomy
- Department of Materials and Science Engineering, Rutgers University, Piscataway, NJ 08854, USA
- Institute for Advanced Materials, Devices, and Nanotechnology, Rutgers University, Piscataway, NJ 08854, USA
| | - Ulrich Hohenester
- Institute of Physics, University of Graz, Universitätsplatz 5, Graz 8010, Austria
| | - Philip E Batson
- Department of Physics and Astronomy
- Department of Materials and Science Engineering, Rutgers University, Piscataway, NJ 08854, USA
- Institute for Advanced Materials, Devices, and Nanotechnology, Rutgers University, Piscataway, NJ 08854, USA
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46
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Wu Y, Li G, Camden JP. Probing Nanoparticle Plasmons with Electron Energy Loss Spectroscopy. Chem Rev 2017; 118:2994-3031. [DOI: 10.1021/acs.chemrev.7b00354] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Yueying Wu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Guoliang Li
- Center for Electron Microscopy, Institute for New Energy Materials and Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China
| | - Jon P. Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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47
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Bellido EP, Bernasconi GD, Rossouw D, Butet J, Martin OJF, Botton GA. Self-Similarity of Plasmon Edge Modes on Koch Fractal Antennas. ACS NANO 2017; 11:11240-11249. [PMID: 29083865 DOI: 10.1021/acsnano.7b05554] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We investigate the plasmonic behavior of Koch snowflake fractal geometries and their possible application as broadband optical antennas. Lithographically defined planar silver Koch fractal antennas were fabricated and characterized with high spatial and spectral resolution using electron energy loss spectroscopy. The experimental data are supported by numerical calculations carried out with a surface integral equation method. Multiple surface plasmon edge modes supported by the fractal structures have been imaged and analyzed. Furthermore, by isolating and reproducing self-similar features in long silver strip antennas, the edge modes present in the Koch snowflake fractals are identified. We demonstrate that the fractal response can be obtained by the sum of basic self-similar segments called characteristic edge units. Interestingly, the plasmon edge modes follow a fractal-scaling rule that depends on these self-similar segments formed in the structure after a fractal iteration. As the size of a fractal structure is reduced, coupling of the modes in the characteristic edge units becomes relevant, and the symmetry of the fractal affects the formation of hybrid modes. This analysis can be utilized not only to understand the edge modes in other planar structures but also in the design and fabrication of fractal structures for nanophotonic applications.
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Affiliation(s)
- Edson P Bellido
- Department of Materials Science and Engineering, McMaster University , 1280 Main Street W., Hamilton, Ontario L8S 4L7, Canada
| | - Gabriel D Bernasconi
- Nanophotonics and Metrology Laboratory, École Polytechnique Fédéralede Lausanne , 1015 Lausanne, Switzerland
| | - David Rossouw
- Department of Materials Science and Engineering, McMaster University , 1280 Main Street W., Hamilton, Ontario L8S 4L7, Canada
| | - Jérémy Butet
- Nanophotonics and Metrology Laboratory, École Polytechnique Fédéralede Lausanne , 1015 Lausanne, Switzerland
| | - Olivier J F Martin
- Nanophotonics and Metrology Laboratory, École Polytechnique Fédéralede Lausanne , 1015 Lausanne, Switzerland
| | - Gianluigi A Botton
- Department of Materials Science and Engineering, McMaster University , 1280 Main Street W., Hamilton, Ontario L8S 4L7, Canada
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48
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Miao X, Guo K, Qian C, Wang J, Zhao D, Fung KH. Electron-beam excited photon emission from monopole modes of a plasmonic nano-disc. OPTICS LETTERS 2017; 42:3387-3390. [PMID: 28957111 DOI: 10.1364/ol.42.003387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/03/2017] [Indexed: 05/22/2023]
Abstract
Plasmonic dark modes are not easy to be observed in the far field due to their weak photon emission. By contrast, it has been shown that a dark mode can be excited effectively by a near-field source such as an electron beam. In this Letter, we show theoretically that the photon emission from the monopole-like dark mode supported on a plasmonic nano-disc could be unexpectedly strong when excited by an electron beam through its hole. Even though this monopole mode is considered to be dark, it is found that the emission can be even "brighter" than the dipolar bright modes when the electron speed is higher than 0.6c. Due to the high conversion efficiency from electron energy loss to photon energy, the results could also suggest an optical method for the detection of high-energy electrons passing through the hole with negligible changes in electron speed.
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49
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Li C, Wang P, Tian Y, Xu X, Hou H, Wang M, Qi G, Jin Y. Long-Range Plasmon Field and Plasmoelectric Effect on Catalysis Revealed by Shell-Thickness-Tunable Pinhole-Free Au@SiO2 Core–Shell Nanoparticles: A Case Study of p-Nitrophenol Reduction. ACS Catal 2017. [DOI: 10.1021/acscatal.7b01053] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Chuanping Li
- State Key Laboratory
of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Ping Wang
- State Key Laboratory
of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, People’s Republic of China
| | - Yu Tian
- State Key Laboratory of Supramolecular Structure and
Materials, Jilin University, 2699 Qianjin Avenue, Changchun 130012, People’s Republic of China
| | - Xiaolong Xu
- State Key Laboratory
of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, People’s Republic of China
| | - Hui Hou
- State Key Laboratory
of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Minmin Wang
- State Key Laboratory
of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Guohua Qi
- State Key Laboratory
of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, People’s Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Yongdong Jin
- State Key Laboratory
of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, People’s Republic of China
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50
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Tomographic imaging of the photonic environment of plasmonic nanoparticles. Nat Commun 2017; 8:37. [PMID: 28652567 PMCID: PMC5484695 DOI: 10.1038/s41467-017-00051-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 04/28/2017] [Indexed: 11/08/2022] Open
Abstract
The photonic local density of states (LDOS) governs the enhancement of light-matter interaction at the nanoscale, but despite its importance for nanophotonics and plasmonics experimental local density of states imaging remains extremely challenging. Here we introduce a tomography scheme based on electron microscopy that allows retrieval of the three-dimensional local density of states of plasmonic nanoparticles with nanometre spatial and sub-eV energy resolution. From conventional electron tomography experiments we obtain the three-dimensional morphology of the nanostructure, and use this information to compute an expansion basis for the photonic environment. The expansion coefficients are obtained through solution of an inverse problem using as input electron-energy loss spectroscopy images. We demonstrate the applicability of our scheme for silver nanocuboids and coupled nanodisks, and resolve local density of states enhancements with extreme sub-wavelength dimensions in hot spots located at roughness features or in gaps of coupled nanoparticles.Imaging the photonic local density of states of plasmonic nanoparticles remains extremely challenging. Here, the authors introduce a tomography scheme based on electron microscopy that allows retrieval of the three-dimensional local density of states with nanometre spatial and sub-eV energy resolution.
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