1
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Liu ACY, Davis TJ, Coenen T, Hari S, Voortman LM, Xu Z, Yuan G, Ballard PM, Funston AM, Etheridge J. Modulation of Cathodoluminescence by Surface Plasmons in Silver Nanowires. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2207747. [PMID: 37029699 DOI: 10.1002/smll.202207747] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 02/08/2023] [Indexed: 06/19/2023]
Abstract
The waveguide modes in chemically-grown silver nanowires on silicon nitride substrates are observed using spectrally- and spatially-resolved cathodoluminescence (CL) excited by high-energy electrons in a scanning electron microscope. The presence of a long-range, travelling surface plasmon mode modulates the coupling efficiency of the incident electron energy into the nanowires, which is observed as oscillations in the measured CL with the point of excitation by the focused electron beam. The experimental data are modeled using the theory of surface plasmon polariton modes in cylindrical metal waveguides, enabling the complex mode wavenumbers and excitation strength of the long-range surface plasmon mode to be extracted. The experiments yield insight into the energy transfer mechanisms between fast electrons and coherent oscillations in surface charge density in metal nanowires and the relative amplitudes of the radiative processes excited in the wire by the electron.
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Affiliation(s)
- Amelia C Y Liu
- School of Physics and Astronomy, Monash University, Clayton, Victoria, 3800, Australia
- Monash Centre for Electron Microscopy, Monash University, Clayton, Victoria, 3800, Australia
| | - Timothy J Davis
- School of Physics, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Toon Coenen
- Delmic BV, Kanaalweg 4, Delft, 2628 EB, The Netherlands
| | | | - Lenard M Voortman
- Delmic BV, Kanaalweg 4, Delft, 2628 EB, The Netherlands
- Division of Cell and Chemical Biology, Leiden University Medical Centre, Leiden University, Leiden, 2333 ZC, The Netherlands
| | - Zhou Xu
- Monash Centre for Electron Microscopy, Monash University, Clayton, Victoria, 3800, Australia
| | - Gangcheng Yuan
- ARC Centre of Excellence in Exciton Science and School of Chemistry, Monash University, Clayton, Victoria, 3800, Australia
| | - Patrycja M Ballard
- ARC Centre of Excellence in Exciton Science and School of Chemistry, Monash University, Clayton, Victoria, 3800, Australia
| | - Alison M Funston
- ARC Centre of Excellence in Exciton Science and School of Chemistry, Monash University, Clayton, Victoria, 3800, Australia
| | - Joanne Etheridge
- School of Physics and Astronomy, Monash University, Clayton, Victoria, 3800, Australia
- Monash Centre for Electron Microscopy, Monash University, Clayton, Victoria, 3800, Australia
- Department of Materials Science and Engineering, Monash University, Clayton, Victoria, 3800, Australia
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2
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Chang KH, Lin ZH, Lee PT, Huang JS. Enhancing on/off ratio of a dielectric-loaded plasmonic logic gate with an amplitude modulator. Sci Rep 2023; 13:5020. [PMID: 36977738 PMCID: PMC10050437 DOI: 10.1038/s41598-023-30823-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 03/02/2023] [Indexed: 03/30/2023] Open
Abstract
AbstractPlasmonic waveguides allow focusing, guiding, and manipulating light at the nanoscale and promise the miniaturization of functional optical nanocircuits. Dielectric-loaded plasmonic (DLP) waveguides and logic gates have drawn attention because of their relatively low loss, easy fabrication, and good compatibility with gain and active tunable materials. However, the rather low on/off ratio of DLP logic gates remains the main challenge. Here, we introduce an amplitude modulator and theoretically demonstrate an enhanced on/off ratio of a DLP logic gate for XNOR operation. Multimode interference (MMI) in DLP waveguide is precisely calculated for the design of the logic gate. Multiplexing and power splitting at arbitrary multimode numbers have been theoretically analyzed with respect to the size of the amplitude modulator. An enhanced on/off ratio of 11.26 dB has been achieved. The proposed amplitude modulator can also be used to optimize the performance of other logic gates or MMI-based plasmonic functional devices.
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3
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Fu M, Mota MPDSP, Xiao X, Jacassi A, Güsken NA, Chen Y, Xiao H, Li Y, Riaz A, Maier SA, Oulton RF. Near-unity Raman β-factor of surface-enhanced Raman scattering in a waveguide. NATURE NANOTECHNOLOGY 2022; 17:1251-1257. [PMID: 36302960 DOI: 10.1038/s41565-022-01232-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 09/07/2022] [Indexed: 05/26/2023]
Abstract
The Raman scattering of light by molecular vibrations is a powerful technique to fingerprint molecules through their internal bonds and symmetries. Since Raman scattering is weak1, methods to enhance, direct and harness it are highly desirable, and this has been achieved using optical cavities2, waveguides3-6 and surface-enhanced Raman scattering (SERS)7-9. Although SERS offers dramatic enhancements2,6,10,11 by localizing light within vanishingly small hot-spots in metallic nanostructures, these tiny interaction volumes are only sensitive to a few molecules, yielding weak signals12. Here we show that SERS from 4-aminothiophenol molecules bonded to a plasmonic gap waveguide is directed into a single mode with >99% efficiency. Although sacrificing a confinement dimension, we find a SERS enhancement of ~103 times across a broad spectral range enabled by the waveguide's larger sensing volume and non-resonant waveguide mode. Remarkably, this waveguide SERS is bright enough to image Raman transport across the waveguides, highlighting the role of nanofocusing13-15 and the Purcell effect16. By analogy to the β-factor from laser physics10,17-20, the near-unity Raman β-factor we observe exposes the SERS technique to alternative routes for controlling Raman scattering. The ability of waveguide SERS to direct Raman scattering is relevant to Raman sensors based on integrated photonics7-9 with applications in gas sensing and biosensing.
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Affiliation(s)
- Ming Fu
- Blackett Laboratory, Imperial College London, London, UK
| | | | - Xiaofei Xiao
- Blackett Laboratory, Imperial College London, London, UK
| | - Andrea Jacassi
- Blackett Laboratory, Imperial College London, London, UK
| | - Nicholas A Güsken
- Blackett Laboratory, Imperial College London, London, UK
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, USA
| | - Yuxin Chen
- Blackett Laboratory, Imperial College London, London, UK
| | - Huaifeng Xiao
- Blackett Laboratory, Imperial College London, London, UK
| | - Yi Li
- Blackett Laboratory, Imperial College London, London, UK
- School of Microelectronics, MOE Engineering Research Center of Integrated Circuits for Next Generation Communications, Southern University of Science and Technology, Shenzhen, China
| | - Ahad Riaz
- Blackett Laboratory, Imperial College London, London, UK
| | - Stefan A Maier
- Blackett Laboratory, Imperial College London, London, UK
- School of Physics and Astronomy, Monash University, Clayton, Victoria, Australia
- Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, Munich, Germany
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4
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Greenwood A, Balram KC, Gersen H. Smooth Sidewalls on Crystalline Gold through Facet-Selective Anisotropic Reactive Ion Etching: Toward Low-Loss Plasmonic Devices. NANO LETTERS 2022; 22:4617-4621. [PMID: 35652540 PMCID: PMC9228404 DOI: 10.1021/acs.nanolett.1c04405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 05/28/2022] [Indexed: 06/15/2023]
Abstract
Quantum plasmonics aims to harness the deeply subwavelength confinement provided by plasmonic devices to engineer more efficient interfaces to quantum systems in particular single emitters. Realizing this vision is hampered by the roughness-induced scattering and loss inherent in most nanofabricated devices. In this work, we show evidence of a reactive ion etching process to selectively etch gold along select crystalline facets. Since the etch is facet selective, the sidewalls of fabricated devices are smoother than the lithography induced line-edge roughness with the prospect of achieving atomic smoothness by further optimization of the etch chemistry. This opens up a route toward fabricating integrated plasmonic circuits that can achieve loss metrics close to fundamental bounds.
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Affiliation(s)
- Alexander
B. Greenwood
- Nanophotonics
and Nanophysics Group, H. H. Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, United Kingdom
| | - Krishna C. Balram
- Quantum
Engineering Technology Laboratories and Department of Electrical and
Electronic Engineering, University of Bristol, Woodland Road, Bristol BS8 1UB, United
Kingdom
| | - Henkjan Gersen
- Nanophotonics
and Nanophysics Group, H. H. Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL, United Kingdom
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5
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Towards Perfect Ultra-Broadband Absorbers, Ultra-Narrow Waveguides, and Ultra-Small Cavities at Optical Frequencies. NANOMATERIALS 2022; 12:nano12132132. [PMID: 35807967 PMCID: PMC9268687 DOI: 10.3390/nano12132132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/14/2022] [Accepted: 06/20/2022] [Indexed: 01/27/2023]
Abstract
In this study, we design ultra-broadband optical absorbers, ultra-narrow optical waveguides, and ultra-small optical cavities comprising two-dimensional metallic photonic crystals that tolerate fabrication imperfections such as position and radius disorderings. The absorbers containing gold rods show an absorption amplitude of more than 90% under 54% position disordering at 200<λ<530 nm. The absorbers containing silver rods show an absorptance of more than 90% under 54% position disordering at 200<λ<400 nm. B-type straight waveguides that contain four rows of silver rods exposed to air reveal normalized transmittances of 75% and 76% under 32% position and 60% radius disorderings, respectively. B-type L-shaped waveguides containing four rows of silver rods show 76% and 90% normalized transmittances under 32% position and 40% radius disorderings, respectively. B-type cavities containing two rings of silver rods reveal 70% and 80% normalized quality factors under 32% position and 60% radius disorderings, respectively.
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6
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Schörner C, Lippitz M. High-Q plasmonic nanowire-on-mirror resonators by atomically smooth single-crystalline silver flakes. J Chem Phys 2021; 155:234202. [PMID: 34937368 DOI: 10.1063/5.0074387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Plasmonic nanoparticles in close vicinity to a metal surface confine light to nanoscale volumes within the insulating gap. With gap sizes in the range of a few nanometers or below, atomic-scale dynamical phenomena within the nanogap come into reach. However, at these tiny scales, an ultra-smooth material is a crucial requirement. Here, we demonstrate large-scale (50 μm) single-crystalline silver flakes with a truly atomically smooth surface, which are an ideal platform for vertically assembled silver plasmonic nanoresonators. We investigate crystalline silver nanowires in a sub-2 nm separation to the silver surface and observe narrow plasmonic resonances with a quality factor Q of about 20. We propose a concept toward the observation of the spectral diffusion of the lowest-frequency cavity plasmon resonance and present first measurements. Our study demonstrates the benefit of using purely crystalline silver for plasmonic nanoparticle-on-mirror resonators and further paves the way toward the observation of dynamic phenomena within a nanoscale gap.
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Affiliation(s)
| | - Markus Lippitz
- Experimental Physics III, University of Bayreuth, Bayreuth, Germany
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7
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Luo S, Hoff BH, Maier SA, de Mello JC. Scalable Fabrication of Metallic Nanogaps at the Sub-10 nm Level. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2102756. [PMID: 34719889 PMCID: PMC8693066 DOI: 10.1002/advs.202102756] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/09/2021] [Indexed: 06/01/2023]
Abstract
Metallic nanogaps with metal-metal separations of less than 10 nm have many applications in nanoscale photonics and electronics. However, their fabrication remains a considerable challenge, especially for applications that require patterning of nanoscale features over macroscopic length-scales. Here, some of the most promising techniques for nanogap fabrication are evaluated, covering established technologies such as photolithography, electron-beam lithography (EBL), and focused ion beam (FIB) milling, plus a number of newer methods that use novel electrochemical and mechanical means to effect the patterning. The physical principles behind each method are reviewed and their strengths and limitations for nanogap patterning in terms of resolution, fidelity, speed, ease of implementation, versatility, and scalability to large substrate sizes are discussed.
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Affiliation(s)
- Sihai Luo
- Department of ChemistryNorwegian University of Science and Technology (NTNU)TrondheimNO‐7491Norway
| | - Bård H. Hoff
- Department of ChemistryNorwegian University of Science and Technology (NTNU)TrondheimNO‐7491Norway
| | - Stefan A. Maier
- Nano‐Institute MunichFaculty of PhysicsLudwig‐Maximilians‐Universität MünchenMünchen80539Germany
- Blackett LaboratoryDepartment of PhysicsImperial College LondonLondonSW7 2AZUK
| | - John C. de Mello
- Department of ChemistryNorwegian University of Science and Technology (NTNU)TrondheimNO‐7491Norway
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8
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Ochs M, Zurak L, Krauss E, Meier J, Emmerling M, Kullock R, Hecht B. Nanoscale Electrical Excitation of Distinct Modes in Plasmonic Waveguides. NANO LETTERS 2021; 21:4225-4230. [PMID: 33929199 DOI: 10.1021/acs.nanolett.1c00182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The electrical excitation of guided plasmonic modes at the nanoscale enables integration of optical nanocircuitry into nanoelectronics. In this context, exciting plasmons with a distinct modal field profile constitutes a key advantage over conventional single-mode integrated photonics. Here, we demonstrate the selective electrical excitation of the lowest-order symmetric and antisymmetric plasmonic modes in a two-wire transmission line. We achieve mode selectivity by precisely positioning nanoscale excitation sources, i.e., junctions for inelastic electron tunneling, within the respective modal field distribution. By using advanced fabrication that combines focused He-ion beam milling and dielectrophoresis, we control the location of tunnel junctions with sub-10 nm accuracy. At the far end of the two-wire transmission line, the guided plasmonic modes are converted into far-field radiation at separate spatial positions showing two distinct orthogonal polarizations. Hence, the resulting device represents the smallest electrically driven light source with directly switchable polarization states with possible applications in display technology.
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Affiliation(s)
- Maximilian Ochs
- NanoOptics & Biophotonics Group, Experimental Physics 5, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Luka Zurak
- NanoOptics & Biophotonics Group, Experimental Physics 5, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Enno Krauss
- NanoOptics & Biophotonics Group, Experimental Physics 5, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Jessica Meier
- NanoOptics & Biophotonics Group, Experimental Physics 5, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Monika Emmerling
- NanoOptics & Biophotonics Group, Experimental Physics 5, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - René Kullock
- NanoOptics & Biophotonics Group, Experimental Physics 5, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Bert Hecht
- NanoOptics & Biophotonics Group, Experimental Physics 5, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
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9
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Li Z, Sun F, Zheng Z, Chen J, Davydov AV, Deng S, Zhang H, Chen H, Liu F. High-Quality All-Inorganic Perovskite CsPbBr 3 Microsheet Crystals as Low-Loss Subwavelength Exciton-Polariton Waveguides. NANO LETTERS 2021; 21:1822-1830. [PMID: 33560855 DOI: 10.1021/acs.nanolett.0c04908] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nanostructured all-inorganic metal halide perovskites have attracted considerable attention due to their outstanding photonic and optoelectronic properties. Particularly, they can exhibit room-temperature exciton-polaritons (EPs) capable of confining electromagnetic fields down to the subwavelength scale, enabling efficient light harvesting and guiding. However, a real-space nanoimaging study of the EPs in perovskite crystals is still absent. Additionally, few studies focused on the ambient-pressure and reliable fabrication of large-area CsPbBr3 microsheets. Here, CsPbBr3 orthorhombic microsheet single crystals were successfully synthesized under ambient pressure. Their EPs were examined using a real-space nanoimaging technique, which reveal EP waveguide modes spanning the visible to near-infrared spectral region. The EPs exhibit a sufficient long propagation length of over 16 μm and a very low propagation loss of less than 0.072 dB·μm-1. These results demonstrate the potential applications of CsPbBr3 microsheets as subwavelength waveguides in integrated optics.
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Affiliation(s)
- Zijuan Li
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, and School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Fengsheng Sun
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, and School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Zebo Zheng
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, and School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Jun Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, and School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Albert V Davydov
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Shaozhi Deng
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, and School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Huairuo Zhang
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
- Theiss Research, Inc., La Jolla, California 92037, United States
| | - Huanjun Chen
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, and School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Fei Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, and School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
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10
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Kumar S, Wu C, Komisar D, Kan Y, Kulikova LF, Davydov VA, Agafonov VN, Bozhevolnyi SI. Fluorescence enhancement of a single germanium vacancy center in a nanodiamond by a plasmonic Bragg cavity. J Chem Phys 2021; 154:044303. [PMID: 33514119 DOI: 10.1063/5.0033507] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Germanium vacancy (GeV) centers in diamonds constitute a promising platform for single-photon sources to be used in quantum information technologies. Emission from these color centers can be enhanced by utilizing a cavity that is resonant at the peak emission wavelength. We investigate circular plasmonic Bragg cavities for enhancing the emission from single GeV centers in nanodiamonds (NDs) at the zero phonon line. Following simulations of the enhancement for different configuration parameters, the appropriately designed Bragg cavities together with out-coupling gratings composed of hydrogen silsesquioxane ridges are fabricated around the NDs containing nitrogen vacancy centers deposited on a silica-coated silver surface. We characterize the fabricated configurations and finely tune the cavity parameters to match the GeV emission. Finally, we fabricate the cavity containing a single GeV-ND and compare the total decay-rate before and after cavity fabrication, finding a decay-rate enhancement of ∼5.5 and thereby experimentally confirming the feasibility of emission enhancement with circular plasmonic cavities.
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Affiliation(s)
- Shailesh Kumar
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, Odense M DK-5230, Denmark
| | - Cuo Wu
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, Odense M DK-5230, Denmark
| | - Danylo Komisar
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, Odense M DK-5230, Denmark
| | - Yinhui Kan
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, Odense M DK-5230, Denmark
| | - Liudmilla F Kulikova
- L.F. Vereshchagin Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk, Moscow 142190, Russia
| | - Valery A Davydov
- L.F. Vereshchagin Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk, Moscow 142190, Russia
| | | | - Sergey I Bozhevolnyi
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, Odense M DK-5230, Denmark
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11
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Park SM, Lee KS, Kim JH, Yeon GJ, Shin HH, Park S, Kim ZH. Direct Visualization of Gap-Plasmon Propagation on a Near-Touching Nanowire Dimer. J Phys Chem Lett 2020; 11:9313-9320. [PMID: 33089991 DOI: 10.1021/acs.jpclett.0c02494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Dimers of metallic nanowires (NWs) with nanometric gaps could be an alternative to overcome the limitations of existing plasmonic waveguides. The gap-surface plasmon polaritons (gap-SPPs) of the dimers may propagate along the NW without crosstalk and greatly enhance the coupling efficiency with an emitter, enabling ultracompact optical circuits. Such a possibility has not been realized, and we experimentally show its possibility. The gap-SPPs of the AgNW-molecule-AgNW structure, with a gap of 3-5 nm defined by the molecules, are visualized using the surface-enhanced Raman scattering (SERS) of the molecules. The SERS images, representing the gap-field intensity distribution, reveal the decay and beating of the monopole-monopole and dipole-dipole gap modes. The propagation lengths of the two (l1 = 0.5-2 μm and l2 = 5-8 μm) closely follow the model prediction with a uniform gap, confirming that the scattering loss induced by the gap irregularities is surprisingly low.
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Affiliation(s)
- Sang-Min Park
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - Kang Sup Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - Jin-Ho Kim
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
| | - Gyu Jin Yeon
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - Hyun-Hang Shin
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - Sangwon Park
- Department of Biophysics and Chemical Biology, Seoul National University, Seoul 08826, Korea
| | - Zee Hwan Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
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12
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Chen TY, Tyagi D, Chang YC, Huang CB. A Polarization-Actuated Plasmonic Circulator. NANO LETTERS 2020; 20:7543-7549. [PMID: 32986442 DOI: 10.1021/acs.nanolett.0c03008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A circulator for surface plasmon polaritons (SPPs) based on a plasmonic two-wire transmission-line (TWTL) structure is experimentally realized. A TWTL offers two distinct plasmon modes that can be independently excited, solely determined by the polarization of the laser field. Through controlled superposition of the two modes, TWTLs are exploited to enable polarization-actuated plasmonic circulators. In the first demonstration, the coupling antennas to the plasmonic circulator are designed to circulate SPPs sensitive to linearly polarized excitation. In the second design, the circulator reacts to the spin angular momenta carried by circularly polarized laser excitations. In both cases, the SPP circulation directions are directly controlled by the laser polarization, and the number of ports is easily expandable. Experimentally, a wide optical operational bandwidth of ∼100 nm is achieved. The results show a major step toward the realization of multifunctioning photonic nanocircuitry.
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Affiliation(s)
- Tzu-Yu Chen
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Dhruv Tyagi
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yun-Chorng Chang
- Research Center for Applied Science, Academia Sinica, Nangang 11529, Taipei, Taiwan
| | - Chen-Bin Huang
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan
- Research Center for Applied Science, Academia Sinica, Nangang 11529, Taipei, Taiwan
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13
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Integration of Single-Photon Emitters in 2D Materials with Plasmonic Waveguides at Room Temperature. NANOMATERIALS 2020; 10:nano10091663. [PMID: 32854316 PMCID: PMC7559460 DOI: 10.3390/nano10091663] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 08/15/2020] [Accepted: 08/23/2020] [Indexed: 11/16/2022]
Abstract
Efficient integration of a single-photon emitter with an optical waveguide is essential for quantum integrated circuits. In this study, we integrated a single-photon emitter in a hexagonal boron nitride (h-BN) flake with a Ag plasmonic waveguide and measured its optical properties at room temperature. First, we performed numerical simulations to calculate the efficiency of light coupling from the emitter to the Ag plasmonic waveguide, depending on the position and polarization of the emitter. In the experiment, we placed a Ag nanowire, which acted as the plasmonic waveguide, near the defect of the h-BN, which acted as the single-photon emitter. The position and direction of the nanowire were precisely controlled using a stamping method. Our time-resolved photoluminescence measurement showed that the single-photon emission from the h-BN flake was enhanced to almost twice the intensity as a result of the coupling with the Ag nanowire. We expect these results to pave the way for the practical implementation of on-chip nanoscale quantum plasmonic integrated circuits.
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14
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Prämassing M, Liebtrau M, Schill HJ, Irsen S, Linden S. Interferometric near-field characterization of plasmonic slot waveguides in single- and poly-crystalline gold films. OPTICS EXPRESS 2020; 28:12998-13007. [PMID: 32403782 DOI: 10.1364/oe.384629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 03/11/2020] [Indexed: 06/11/2023]
Abstract
Single-crystalline gold films show superior plasmonic properties compared to their poly-crystalline counterparts. However, this advantage comes at the cost of a more complex preparation process. It is thus crucial to validate whether the impact of the material quality on the performance of the respective plasmonic device justifies this additional effort. In order to address this question for the case of plasmonic slot waveguides, we present interferometric near-field measurements at telecommunication wavelengths on slot waveguides in single- and poly-crystalline gold films. We observe significantly larger propagation lengths in the case of single-crystalline gold films for slot widths below 100 nm. In contrast for larger widths, both gold films give rise to comparable propagation lengths.
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15
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Schörner C, Lippitz M. Single Molecule Nonlinearity in a Plasmonic Waveguide. NANO LETTERS 2020; 20:2152-2156. [PMID: 32077703 DOI: 10.1021/acs.nanolett.0c00196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Plasmonic waveguides offer the unique possibility to confine light far below the diffraction limit. Past room temperature experiments focused on efficient generation of single waveguide plasmons by a quantum emitter. However, only the simultaneous interaction of the emitter with multiple plasmonic fields would lead to functionality in a plasmonic circuit. Here, we demonstrate the nonlinear optical interaction of a single molecule and propagating plasmons. An individual terrylene diimide (TDI) molecule is placed in the nanogap between two single-crystalline silver nanowires. A visible wavelength pump pulse and a red-shifted depletion pulse travel along the waveguide, leading to stimulated emission depletion (STED) in the observed fluorescence. The efficiency increases by up to a factor of 50 compared to far-field excitation. Our study thus demonstrates remote nonlinear four-wave mixing at a single molecule with propagating plasmons. It paves the way toward functional quantum plasmonic circuits and improved nonlinear single-molecule spectroscopy.
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Affiliation(s)
- Christian Schörner
- Experimental Physics III, University of Bayreuth, Bayreuth, Germany D-95447
| | - Markus Lippitz
- Experimental Physics III, University of Bayreuth, Bayreuth, Germany D-95447
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