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Doležal J, Sagwal A, de Campos Ferreira RC, Švec M. Single-Molecule Time-Resolved Spectroscopy in a Tunable STM Nanocavity. NANO LETTERS 2024; 24:1629-1634. [PMID: 38286028 PMCID: PMC10853955 DOI: 10.1021/acs.nanolett.3c04314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/23/2024] [Accepted: 01/23/2024] [Indexed: 01/31/2024]
Abstract
Spontaneous fluorescence rates of single-molecule emitters are typically on the order of nanoseconds. However, coupling them with plasmonic nanostructures can substantially increase their fluorescence yields. The confinement between a tip and sample in a scanning tunneling microscope creates a tunable nanocavity, an ideal platform for exploring the yields and excitation decay rates of single-molecule emitters, depending on their coupling strength to the nanocavity. With such a setup, we determine the excitation lifetimes from the direct time-resolved measurements of phthalocyanine fluorescence decays, decoupled from the metal substrates by ultrathin NaCl layers. We find that when the tip is approached to single molecules, their lifetimes are reduced to the picosecond range due to the effect of coupling with the tip-sample nanocavity. On the other hand, ensembles of the adsorbed molecules measured without the nanocavity manifest nanosecond-range lifetimes. This approach overcomes the drawbacks associated with the estimation of lifetimes for single molecules from their respective emission line widths.
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Affiliation(s)
- Jiří Doležal
- Institute
of Physics, Czech Academy of Sciences; Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
| | - Amandeep Sagwal
- Institute
of Physics, Czech Academy of Sciences; Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
- Faculty
of Mathematics and Physics, Charles University; Ke Karlovu 3, CZ12116 Praha 2, Czech Republic
| | | | - Martin Švec
- Institute
of Physics, Czech Academy of Sciences; Cukrovarnická 10/112, CZ16200 Praha 6, Czech Republic
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Flemingovo náměstí 542/2, CZ16000 Praha 6, Czech Republic
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2
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Wan M, Wu J, Liu J, Chen Z, Gu P, Zhan P, Wang Z, Bozhevolnyi SI. Dielectric-loading approach for extra electric field enhancement and spatially transferring plasmonic hot-spots. NANOTECHNOLOGY 2021; 32:035205. [PMID: 33094736 DOI: 10.1088/1361-6528/abaf7f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Plasmonic nanoantennas have been widely explored for boosting up light-matter interactions due to their ability of providing strongly confined and highly enhanced electric near fields, so called 'hot-spots'. Here, we propose a dielectric-loading approach for hot-spots engineering by coating the conventional plasmonic nanoantennas with a conformal high refractive index dielectric film and forming dielectric-loaded plasmonic nanoantennas. Compared to the conventional plasmonic nanoantennas, the corresponding dielectric-loaded ones that resonate at the same frequency are able to provide an extra enhancement in the local electric fields and meanwhile spatially transfer the hot spots to the dielectric surfaces. These findings have important implications for the design of optical nanoantennas with general applications in surface enhanced linear and nonlinear spectroscopies. As a demonstration application, we show that the maximum achievable fluorescence intensity in the dielectric-loaded plasmonic nanoantennas could be significantly larger than that in the conventional plasmonic nanoantennas.
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Affiliation(s)
- Mingjie Wan
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Jingyu Wu
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Jun Liu
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Zhuo Chen
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Ping Gu
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Peng Zhan
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Zhenlin Wang
- National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Sergey I Bozhevolnyi
- Centre for Nano Optics, University of Southern Denmark, Campusvej 55, Odense M DK-5230, Denmark
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3
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Liu J, Chen YG, Gan L, Xiao TH, Li ZY. Realization of Plasmonic Microcavity with Full Transverse and Longitudinal Mode Selection. Sci Rep 2016; 6:27565. [PMID: 27273163 PMCID: PMC4897782 DOI: 10.1038/srep27565] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 05/20/2016] [Indexed: 11/09/2022] Open
Abstract
Surface plasmon polaritons (SPPs) manipulation is of vital importance to construct ultracompact integrated micro/nano-optical devices and systems. Here we report the design, fabrication, and characterization of a SPP microcavity with full transverse and longitudinal mode selection and control on the surface of gold film. The designed microcavity supports the fundamental and first-order transverse modes of Gaussian mode beam with controllable longitudinal modes, respectively. The transverse mode is determined by two holographic mirrors made from deliberately designed groove patterns via the surface electromagnetic wave holography methodology, while the longitudinal mode is determined by the length of cavity. Both numerical simulations and leaky-wave SPP mode observations confirm the realization of full mode selection in the fabricated cavity. Our work opens up a powerful way to fully explore longitudinal and transverse mode control in SPP microcavities, which will be beneficial for light-matter interaction enhancement, construction of novel SPP nanolaser and microlaser, optical sensing, and optical information processing.
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Affiliation(s)
- Ju Liu
- Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Science, P. O. Box 603, Beijing 100190, China
| | - Yue-Gang Chen
- Department of Physics, Guizhou University, Guiyang, 550025, China
| | - Lin Gan
- Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Science, P. O. Box 603, Beijing 100190, China
| | - Ting-Hui Xiao
- Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Science, P. O. Box 603, Beijing 100190, China
| | - Zhi-Yuan Li
- Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Science, P. O. Box 603, Beijing 100190, China
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4
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Akselrod GM, Walker BJ, Tisdale WA, Bawendi MG, Bulovic V. Twenty-fold enhancement of molecular fluorescence by coupling to a J-aggregate critically coupled resonator. ACS NANO 2012; 6:467-471. [PMID: 22122758 DOI: 10.1021/nn203789t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report a 20-fold enhancement in the fluorescence of the organic dye DCM when resonantly coupled to a strongly optically absorbing structure of a thin film of spin-deposited molecular J-aggregates in a critically coupled resonator (JCCR) geometry. A submonolayer equivalent of DCM molecules is shown to absorb and re-emit 2.2% of the incident resonant photons when coupled to the JCCR enhancement structure, compared to 0.1% for the bare film of same thickness on quartz. Such a JCCR structure is a general energy focusing platform that localizes over 90% of incident light energy within a 15 nm thin film layer in the form of excitons that can subsequently be transferred to colocated lumophores. Applications of the exciton-mediated concentration of optical energy are discussed in the context of solid-state lighting, photodetection, and single photon optics.
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Affiliation(s)
- Gleb M Akselrod
- Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 13-3146, Cambridge, Massachusetts 02139, USA.
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5
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Rossouw D, Couillard M, Vickery J, Kumacheva E, Botton GA. Multipolar plasmonic resonances in silver nanowire antennas imaged with a subnanometer electron probe. NANO LETTERS 2011; 11:1499-504. [PMID: 21446717 DOI: 10.1021/nl200634w] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We detect short-range surface plasmon-polariton (SR-SPP) resonances setup in individual silver nanoantenna structures at high-spatial resolution with a scanning, subnanometer electron probe. Both even and odd multipolar resonant modes are resolved up to sixth order, and we measure their spatial distribution in relation to nanoantenna structures at energies down to 0.55 eV. Fabry-Perot type SR-SPP reflection phase shifts are calculated from direct measurements of antinode spacings in high-resolution plasmonic field maps. We observe resonant SR-SPP antinode bunching at nanoantenna terminals in high-order resonant modes, and antinode shifts in nonhomogeneous local environments. Finally, we achieve good agreement of our experimental SR-SPP maps with numerical calculations of photon excited near fields, using a novel integrated photon excitation geometry.
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Affiliation(s)
- D Rossouw
- Department of Materials Science and Engineering, McMaster University, 1280 Main Street W. Hamilton ON, L8S 4L7, Canada
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6
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Nath S, Jana S, Pradhan M, Pal T. Ligand-stabilized metal nanoparticles in organic solvent. J Colloid Interface Sci 2009; 341:333-52. [PMID: 19880134 DOI: 10.1016/j.jcis.2009.09.049] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Revised: 09/19/2009] [Accepted: 09/24/2009] [Indexed: 11/16/2022]
Abstract
This critical review reports the fundamental behavior of metal nanoparticles in different organic solvents, i.e., metal organosol. An overview on metal organosol and then their smart synthetic approaches, characterization, and potential applications in the fields of catalysis and spectroscopy with special emphasis on SERS are embodied. Aspects of organosol fabrication, stabilization, morphology control, growth mechanisms, and physical properties as mono- and bimetallic nanoparticles are discussed. The article inspires the repetitive usage of metal nanoparticles as stable deliverable organic and molecular compounds.
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Affiliation(s)
- Sudip Nath
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721 302, India
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7
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Toropov AA, Shubina TV, Jmerik VN, Ivanov SV, Ogawa Y, Minami F. Optically enhanced emission of localized excitons in InxGa1-xN films by coupling to plasmons in a gold nanoparticle. PHYSICAL REVIEW LETTERS 2009; 103:037403. [PMID: 19659316 DOI: 10.1103/physrevlett.103.037403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Indexed: 05/07/2023]
Abstract
We report on strong site-selective enhancement of the emission of localized excitons in an InxGa1-xN film, induced by resonant coupling to a single plasmon confined in a gold nanoparticle. The particle was attached to an atomic-force-microscope probe and placed at the near-field distance of the surface. The observation is explained by the enhancement of the spontaneous emission recombination rate of the excitons due to the local increase in the photonic mode density near the metal particle. The interpretation is consistent with the intensity increase and lifetime shortening of the emission observed in the same film with deposited Au clusters. We show that the nanoscale roughness of the film is an important prerequisite of the efficient plasmonic enhancement.
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Affiliation(s)
- A A Toropov
- Ioffe Physical-Technical Institute, Russian Academy of Sciences, 26 Polytekhnicheskaya, St. Petersburg 194021, Russia
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8
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Kim ZH, Ahn SH, Liu B, Leone SR. Nanometer-scale dielectric imaging of semiconductor nanoparticles: size-dependent dipolar coupling and contrast reversal. NANO LETTERS 2007; 7:2258-62. [PMID: 17608441 DOI: 10.1021/nl070753k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Scattering-type apertureless near-field microscopy (ANSOM) provides high-resolution dielectric maps of indium gallium nitride (InGaN) semiconductor nanoparticles at visible (633 nm) wavelengths. A specific size-dependent contrast reversal is observed in the ANSOM images of InGaN nanoparticles grown on a layer of gallium nitride (GaN). Model calculations demonstrate that the observed contrast reversal is the result of the competition between the tip-particle versus tip-substrate dipolar coupling.
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Affiliation(s)
- Zee Hwan Kim
- Department of Chemistry and Center for Electro- and Photo-Responsive Molecules, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-701, Republic of Korea
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9
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Praharaj S, Ghosh SK, Nath S, Kundu S, Panigrahi S, Basu S, Pal T. Size-selective synthesis and stabilization of gold organosol in C(n)TAC: enhanced molecular fluorescence from gold-bound fluorophores. J Phys Chem B 2007; 109:13166-74. [PMID: 16852640 DOI: 10.1021/jp051132n] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gold nanoparticles of variable sizes have been synthesized in toluene employing two-phase (water-toluene) extraction of AuCl4- followed by its reduction with sodium borohydride in the presence of a series of cationic surfactants of a homologous series having the general formula C(n)TAC. The solubility features of the gold particles in the organic solvent have been accounted qualitatively by calculating the van der Waals interaction potential between the particles. The effect of thermal energy and medium dielectric constant on the stability of metal particles has been studied by measuring the surface plasmon resonance. The stabilization of surfactant-mediated gold particles as hydrosol or organosol has been elucidated by considering the double-layer interaction as a function of the dielectric constant of the solvent medium. The influence of the counterion of the phase transfer reagent and stabilizing ligand on the photochemical stability of the gold colloids has been investigated. The fluorescence probe 1-methylaminopyrene (MAP) was considered for the surface functionalization of the gold particles, and it has been found that there is an enhancement of molecular fluorescence from the gold-probe assembly.
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10
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Diziain S, Bijeon JL, Adam PM, Lamy de la Chapelle M, Thomas B, Déturche R, Royer P. Near-field reflection backscattering apertureless optical microscopy: Application to spectroscopy experiments on opaque samples, comparison between lock-in and digital photon counting detection techniques. Ultramicroscopy 2007; 107:16-24. [PMID: 16735090 DOI: 10.1016/j.ultramic.2006.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2005] [Revised: 03/24/2006] [Accepted: 04/12/2006] [Indexed: 10/24/2022]
Abstract
An apertureless scanning near-field optical microscope (ASNOM) in reflection backscattering configuration is designed to conduct spectroscopic experiments on opaque samples constituted of latex beads. The ASNOM proposed takes advantage of the depth-discrimination properties of confocal microscopes to efficiently extract the near-field optical signal. Given their importance in a spectroscopic experiment, we systematically compare the lock-in and synchronous photon counting detection methods. Some results of Rayleigh's scattering in the near field of the test samples are used to illustrate the possibilities of this technique for reflection backscattering spectroscopy.
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Affiliation(s)
- S Diziain
- Institut Charles Delaunay, CNRS FRE 2848, Laboratoire de Nanotechnologie et d'Instrumentation Optique, Université de technologie de Troyes, 12 rue Marie Curie, BP 2060, 10010 Troyes cedex, France
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11
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Ma Z, Gerton JM, Wade LA, Quake SR. Fluorescence near-field microscopy of DNA at sub-10 nm resolution. PHYSICAL REVIEW LETTERS 2006; 97:260801. [PMID: 17280412 DOI: 10.1103/physrevlett.97.260801] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Indexed: 05/13/2023]
Abstract
We demonstrate apertureless near-field microscopy of single molecules at sub-10 nm resolution. With a novel phase filter, near-field images of single organic fluorophores were obtained with approximately sixfold improvement in the signal-to-noise ratio. The improvement allowed pairs of molecules separated by approximately 15 nm to be reliably and repeatedly resolved, thus demonstrating the first true Rayleigh resolution test for near-field images of single molecules. The potential of this technique for biological applications was demonstrated with an experiment that measured the helical rise of A-form DNA.
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Affiliation(s)
- Ziyang Ma
- Applied Physics and Physics, California Institute of Technology, Pasadena, California 91125, USA
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12
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Kim ZH, Leone SR. High-Resolution Apertureless Near-Field Optical Imaging Using Gold Nanosphere Probes†. J Phys Chem B 2006; 110:19804-9. [PMID: 17020365 DOI: 10.1021/jp061398+] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An apertureless near-field scanning optical microscope (ANSOM) that utilizes the enhanced field around a gold nanosphere, which is attached to the end of an atomic force microscope (AFM) tip, is used to image the local dielectric constant of the patterned metallic surfaces and local electric field around plasmonic nanosphere samples. A colloidal gold nanosphere (approximately 50 nm diameter) is linked to the extremity of the conventional etched-silicon probe. The scattering of laser radiation (633 or 532 nm) is modulated by the oscillating nanosphere-functionalized silicon tip, and the scattered radiation is detected. The approach curve (scattering intensity as a function of the tip-sample distance), the polarization dependence (scattering intensity as a function of the excitation polarization direction), and ANSOM image contrast confirm that the spherical nanosphere attached to the silicon tip acts as a point dipole that interacts with the sample surface via a dipole-dipole coupling, in which the dipole created by the field at the tip interacts with its own image dipole in the sample. The image obtained with the nanoparticle functionalized tip provides a dielectric map of the sample surface with a spatial resolution better than 80 nm. In addition, we show that the functionalized tip is capable of imaging the local electric field distribution above the plasmonic nanosphere samples. Overall, the result shows that high-resolution ANSOM is possible without the aid of the lightning-rod effect. With an improved tip-fabrication method, we believe that the method can provide a versatile high-resolution chemical imaging that is not available from usual forms of ANSOM.
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Affiliation(s)
- Zee Hwan Kim
- Department of Chemistry and Physics, University of California, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, USA
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13
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Abstract
This manuscript reviews the principles and recent advances of scanning near-field optical microscopy based on tip-induced field enhancement. These scanning microscopes utilize minute probes to locally enhance an electromagnetic field through a complex interplay between surface plasmon excitation and localization of electric charges by geometrical singularities. The necessary conditions leading to an electromagnetic enhancement will be reviewed, as well as the means to characterize it. A brief account of the theoretical framework will be given, together with applications of the technique ranging from chemical imaging to nanolithography.
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Affiliation(s)
- Alexandre Bouhelier
- Center for Nanoscale Materials and Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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14
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Schuck PJ, Fromm DP, Sundaramurthy A, Kino GS, Moerner WE. Improving the mismatch between light and nanoscale objects with gold bowtie nanoantennas. PHYSICAL REVIEW LETTERS 2005; 94:017402. [PMID: 15698131 DOI: 10.1103/physrevlett.94.017402] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Indexed: 05/11/2023]
Abstract
Metallic bowtie nanoantennas should provide optical fields that are confined to spatial scales far below the diffraction limit. To improve the mismatch between optical wavelengths and nanoscale objects, we have lithographically fabricated Au bowties with lengths approximately 75 nm and gaps of tens of nm. Using two-photon-excited photoluminescence of Au, the local intensity enhancement factor relative to that for the incident diffraction-limited beam has been experimentally determined for the first time. Enhancements >10(3) occur for 20 nm gap bowties, in good agreement with theoretical simulations.
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Affiliation(s)
- P J Schuck
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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15
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Gerton JM, Wade LA, Lessard GA, Ma Z, Quake SR. Tip-enhanced fluorescence microscopy at 10 nanometer resolution. PHYSICAL REVIEW LETTERS 2004; 93:180801. [PMID: 15525147 DOI: 10.1103/physrevlett.93.180801] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2003] [Indexed: 05/24/2023]
Abstract
We demonstrate unambiguously that the field enhancement near the apex of a laser-illuminated silicon tip decays according to a power law that is moderated by a single parameter characterizing the tip sharpness. Oscillating the probe in intermittent contact with a semiconductor nanocrystal strongly modulates the fluorescence excitation rate, providing robust optical contrast and enabling excellent background rejection. Laterally encoded demodulation yields images with <10 nm spatial resolution, consistent with independent measurements of tip sharpness.
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Affiliation(s)
- Jordan M Gerton
- Department of Applied Physics, California Institute of Technology, MC 128-95, Pasadena, CA 91125, USA
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16
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Howie A. Ultralow-energy excitations and prospects for spatially resolved spectroscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2004; 10:28-33. [PMID: 15306064 DOI: 10.1017/s1431927604040280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2003] [Indexed: 05/24/2023]
Abstract
The key contribution of electron microscopy methods to condensed matter spectroscopy is undoubtedly spatial resolution. So far this has mainly been manifest through electron energy loss spectroscopy in the 1-eV to 10-keV energy range and has not seriously challenged the dominance of optical, X-ray, and neutron spectroscopy methods over most of the vast field at lower energies. At frequencies up to a few megahertz, corresponding to energies of a few nanoelectron volts and below, direct excitation by pulsed electron beams or electric fields has proved effective. Prospects are discussed for extending spatially resolved spectroscopy to the intermediate energy region, mainly by combining the advantages of electrons with those of photons.
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Affiliation(s)
- A Howie
- Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UK.
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17
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Chapter 8 Near-field nano-Raman spectroscopy for molecular analysis and imaging. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/s1574-0641(04)80013-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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18
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Maliwal BP, Malicka J, Gryczynski I, Gryczynski Z, Lakowicz JR. Fluorescence properties of labeled proteins near silver colloid surfaces. Biopolymers 2003; 70:585-94. [PMID: 14648768 PMCID: PMC2737415 DOI: 10.1002/bip.10501] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The fluorescence properties of a monolayer of labeled avidin molecules were studied near silver island films. We first adsorbed a monolayer of biotinylated-BSA as a base that was used to capture labeled avidin molecules. For labeled avidin on silver island films, we observed an increase of the fluorescence intensity of between 18 and 80 with one-photon excitation and up to several hundredfold or larger with two-photon excitation. The probes were moderately more photostable in the presence of silver islands. There was also a dramatic decrease in the lifetimes with the amplitude-weighted values decreasing from 7- to 35-fold. The data suggest that these spectral changes are due to both increased rates of excitation near the metallic particles and increases in the rates of radiative decay. Because these silver island surfaces are very heterogeneous, we are hopeful that larger increases in intensity and photostability can be obtained for probes situated at an optimal distance from the ideal island surfaces.
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Affiliation(s)
- Badri P Maliwal
- Center for Fluorescence Spectroscopy, University of Maryland at Baltimore, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, MD 21201, USA
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19
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Fragola A, Aigouy L, Boccara C. Interference effect in apertureless near-field fluorescence imaging. APPLIED OPTICS 2003; 42:6880-6888. [PMID: 14661799 DOI: 10.1364/ao.42.006880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Apertureless scanning near-field optical microscopy has been used to image fluorescent latex spheres with a resolution of a few tens of nanometers and good signal-to-noise ratio. The near-field fluorescence images reveal optical interference with several highly contrasted fringes located around the spheres. The origin of the interference is discussed in detail, and models are used to explain their formation. Spatial coherence is also discussed.
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Affiliation(s)
- Alexandra Fragola
- Laboratoire d'Optique Physique, Ecole Supérieure de Physique et Chimie Industrielles, Centre National de la Recherche Scientifique A0005, Université Pierre et Marie Curie, 10 rue Vauquelin, 75005 Paris, France.
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20
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Clegg RM, Holub O, Gohlke C. Fluorescence lifetime-resolved imaging: measuring lifetimes in an image. Methods Enzymol 2003; 360:509-42. [PMID: 12622166 DOI: 10.1016/s0076-6879(03)60126-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We have given an overview of what one can gain by lifetime-resolved imaging and reviewed the major issues concerning lifetime-resolved measurements and FLI instrumentation. Instead of giving diverse selected examples, we have discussed the underlying basic pathways of deexcitation available to the molecules in the excited state. It is by traversing these pathways that compete kinetically with the fluorescence pathway of deactivation--and therefore affect the measured fluorescence lifetime--that we gain the information that lifetime-resolved fluorescence provides. It is hoped that being aware of the diversity, of pathways available to an excited fluorophore will facilitate potential users to recognize the value of FLI measurements and inspire innovative experiments using lifetime-resolved imaging. FLI gives us the ability within a fluorescence image of measuring and quantifying dynamic events taking place in the immediate surroundings of fluorophores as well as locating the fluorescent components within the image. Just as measurements in cuvettes, lifetime-resolved imaging extends considerably the potential information that can be derived from a fluorescence experiment. Our purpose has been to arouse an appreciation for the broad application of fluorescence lifetime-resolved measurements in imaging. We have given only general design characteristics of the instrumentation and discussed the characteristics that distinguish imaging from the single channel lifetime-resolved measurements. We have not provided details of the instrumentation or the presented many examples. These are available in the literature, and given in the references, and they are continually and rapidly growing.
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Affiliation(s)
- Robert M Clegg
- Department of Physics, University of Illinois Urbana-Champaign, Urbana 61801, USA
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21
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Cai Y, Peng WP, Kuo SJ, Sabu S, Han CC, Chang HC. Optical detection and charge-state analysis of MALDI-generated particles with molecular masses larger than 5 MDa. Anal Chem 2002; 74:4434-40. [PMID: 12236352 DOI: 10.1021/ac020205l] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Charged polystyrene nanoparticles are generated by matrix-assisted laser desorption/ionization (MALDI) and detected by laser-induced fluorescence (LIF) in a quadrupole ion trap. Employing the LIF technique, observations of individual fluorescent nanospheres (27 nm in diameter and containing 180 fluorescein dye equivalents) have been achieved with an average signal-to-noise ratio of approximately 10. With the trap operating at a frequency around 5 kHz, charge state analysis of the particles reveals that the number of charges carried by the spheres is between 1 and 10. It suggests a mass-to-charge ratio (m/z) in the range of 10(5)-10(6) for the MALDI-generated particles. To effectively trap such large particles (m > 5 MDa), damping of the particles' motions by using approximately 50 mTorr He buffer gas is absolutely required. Similar findings are obtained for particles with a nominal size of 1 microm in diameter, demonstrating that production of charged particles with a molecular mass as high as 10(12) Da is possible using the MALDI technique.
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Affiliation(s)
- Y Cai
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
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Hayazawa N, Inouye Y, Sekkat Z, Kawata S. Near-field Raman imaging of organic molecules by an apertureless metallic probe scanning optical microscope. J Chem Phys 2002. [DOI: 10.1063/1.1485731] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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