Plasmon Coupling in Silver Nanocube Dimers: Resonance Splitting Induced by Edge Rounding

Grillet, Nadia; Manchon, Delphine; Bertorelle, Franck; Bonnet, Christophe; Broyer, M.; Cottancin, E.; Lermé, J.; Hillenkamp, Matthias; Pellarin, M.

doi:10.1021/nn2041329

Cited by 146 publications

(190 citation statements)

References 55 publications

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“…46−49 The coupling does not significantly affect the spectral positions of the two narrow LAP peaks at higher energy, but leads to a significant red-shift with decreasing d sep of the dominant, lowest energy LAP. Critically, and in contrast with the spherical-gap terminations, the red-shift saturates as the gap narrows 24,50 toward the contact d sep = 0 limit, where the lowest energy LAP mode for a single nanorod of length 2L is recovered.…”

Section: ■ Gap-antenna Morphologymentioning

confidence: 92%

The Morphology of Narrow Gaps Modifies the Plasmonic Response

et al. 2015

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ABSTRACT:The optical response of a plasmonic gapantenna is mainly determined by the Coulomb interaction of the two constituent arms of the antenna. Using rigorous calculations supported by simple analytical models, we observe how the morphology of a nanometric gap separating two metallic rods dramatically modifies the plasmonic response. In the case of rounded terminations at the gap, a conventional set of bonding modes is found that red-shifts strongly with decreasing separation. However, in the case of flat surfaces, a distinctly different situation is found with the appearance of two sets of modes: (i) strongly radiating longitudinal antenna plasmons (LAPs), which exhibit a red-shift that saturates for very narrow gaps, and (ii) transverse cavity plasmons (TCPs) confined to the gap, which are weakly radiative and strongly dependent on the separation distance between the two arms. The two sets of modes can be independently tuned, providing detailed control of both the near-and far-field response of the antenna. We illustrate these properties also with an application to larger infrared gap-antennas made of polar materials such as SiC. Finally we use the quantum corrected model (QCM) to show that the morphology of the gap has a dramatic influence on the plasmonic response also for subnanometer gaps. This effect can be crucial for the correct interpretation of charge transfer processes in metallic cavities where quantum effects such as electron tunneling are important. KEYWORDS: optical antennas, plasmonic gaps, cavity modes, antenna modes, quantum effects, quantum corrected model, plasmonic resonances, phononic resonances M etallic particles can show a strong optical response due to the excitation of resonant plasmonic modes, making light manipulation possible in structures of dimensions comparable to or smaller than the wavelength. Typical effects are the efficient emission of radiation and the concentration of the incoming light energy in small volumes, thus justifying the characterization of these metallic structures as optical antennas. 1,2 Modifications of the geometry, size, or materials 3−6 affect the optical response. In particular, the resonant modes of optical antennas consisting of two metallic particles separated by a narrow gap show significant sensitivity to the properties of the gap. 7−19 In an optical antenna, a change in geometry can simultaneously affect both the strength and wavelength of its resonances and modify both the far-and near-field response. It is usually a challenge, for example, to control the near field without affecting the far-field properties. In this theoretical work, we discuss how the coexistence 20,21 of two different and mostly spectrally decoupled types of modes in flat-gap antennas, namely, transverse cavity modes 22 and longitudinal antenna modes, 15 allows for a more flexible tuning of far-and near-field properties compared to that of the conventional spherical-gap terminations 13,17,23 The importance of the gap morphology 24 is particularly pronounced for nanometer-...

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Section: ■ Gap-antenna Morphologymentioning

confidence: 92%

The Morphology of Narrow Gaps Modifies the Plasmonic Response

et al. 2015

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“…The most common and simplistic case of plasmon hybridization is a dimer of two closely located nanostructures [21], and the term is widely used to explain the interaction between two solid nanostructures or the interaction between the nanostructure and the environment, i.e. the substrate [22][23][24][25][26][27][28][29][30][31][32][33][34][35]. In this review, we will focus on the plasmon hybridization in hollow nanostructures [13,20,[36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Hollow metal nanostructures for enhanced plasmonics: synthesis, local plasmonic properties and applications

et al. 2016

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Metallic nanostructures have received great attention due to their ability to generate surface plasmon resonances, which are collective oscillations of conduction electrons of a material excited by an electromagnetic wave. Plasmonic metal nanostructures are able to localize and manipulate the light at the nanoscale and, therefore, are attractive building blocks for various emerging applications. In particular, hollow nanostructures are promising plasmonic materials as cavities are known to have better plasmonic properties than their solid counterparts thanks to the plasmon hybridization mechanism. The hybridization of the plasmons results in the enhancement of the plasmon fields along with more homogeneous distribution as well as the reduction of localized surface plasmon resonance (LSPR) quenching due to absorption. In this review, we summarize the efforts on the synthesis of hollow metal nanostructures with an emphasis on the galvanic replacement reaction. In the second part of this review, we discuss the advancements on the characterization of plasmonic properties of hollow nanostructures, covering the single nanoparticle experiments, nanoscale characterization via electron energy-loss spectroscopy and modeling and simulation studies. Examples of the applications, i.e. sensing, surface enhanced Raman spectroscopy, photothermal ablation therapy of cancer, drug delivery or catalysis among others, where hollow nanostructures perform better than their solid counterparts, are also evaluated.

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“…As shown in Figure 2, for a 5-nm gap, the near-field intensity enhancement can be as high as 300 times at its resonant wavelength of 508 nm. Actually, the enhancement ability is highly related to the particle size, shape [22,23], geometry [26,27,76], and especially the spacing between nanostructures [6,28]. It is known that the coupling strength of the SP between particles increases enormously as the gap between the particles decreases [77].…”

Section: Nanoantenna As a Receivermentioning

confidence: 99%

“…Propagating light can be converted into a nanoscale enhanced near field [17][18][19][20], and vice versa, a localized excitation can be coupled to directed radiation [21]. The efficiency and resonant properties of an optical antenna depend on its shape [22,23], material [24,25], geometry [26][27][28], and operation frequency [29]. Various optical antennas have been developed experimentally and theoretically, such as individual discs [30], triangles [31,32], flowers [33], as well as coupled antenna such as dimers [4,34,35], bowties [9,15], and trimers [12], etc.…”

Section: Introductionmentioning

confidence: 99%

Nanoantenna effect of surface-enhanced Raman scattering: managing light with plasmons at the nanometer scale

2016

Advances in Physics: X

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Manipulating light on the nanometer scale is a challenging topic not only from a fundamental point of view, but also for applications aiming toward the design of miniature optical devices. Nanoplasmonics is a rapidly emerging branch of photonics, which offers variable means to manipulate light using surface plasmon excitations on metal nanostructures. As a spectroscopic phenomenon discovered nearly 40 years ago, surface-enhanced Raman scattering (SERS) has been an active topic of fundamental and applied researches. The dominating electromagnetic enhancement in SERS is caused by surface plasmon resonances. This is a typical example of manipulating light intensity with plasmons. Here, we will review the recent SERS studies related to nanoantenna effects on different metal nanostructures based on electromagnetic enhancement. Three aspects will be the focus in this paper: (1) the coupled nanostructures which act as receiving and emitting antenna that can generate enormous SERS enhancement ~E4 even enough for single molecule SERS. (2) The polarization of SERS at the single molecule limit, including the linear and circular polarizations can be manipulated using designed asymmetric antennas. Such an effect can make the traditional 1/2 and 1/4 wave plates miniaturized to the nanometer scale. (3) Combining nanoantenna and waveguiding effects, remote excitation of SERS can be realized, which may open a new area of single molecule SERS on nanophotonic circuits.

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Plasmon Coupling in Silver Nanocube Dimers: Resonance Splitting Induced by Edge Rounding

Cited by 146 publications

References 55 publications

The Morphology of Narrow Gaps Modifies the Plasmonic Response

The Morphology of Narrow Gaps Modifies the Plasmonic Response

Hollow metal nanostructures for enhanced plasmonics: synthesis, local plasmonic properties and applications

Nanoantenna effect of surface-enhanced Raman scattering: managing light with plasmons at the nanometer scale

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