Plasmons in nearly touching metallic nanoparticles: singular response in the limit of touching dimers.

By I. Romero, Javier Aizpurua, Garnett W. Bryant, F. García de Abajo. Optics Express, 2006

686 citations recorded by the source corpus.

The response of gold nanoparticle dimers is studied theoretically near and beyond the limit where the particles are touching. As the particles approach each other, a dominant dipole feature is observed that is pushed into the infrared due to interparticle coupling and that is associated with a large pileup of induced charge in the interparticle gap. The redshift becomes singular as the particle separation decreases. The response weakens for very small separation when the coupling across the interparticle gap becomes so strong that dipolar oscillations across the pair are inhibited. Lowerwavelength, higher-order modes show a similar separation dependence in nearly touching dimers. After touching, singular behavior is observed through the emergence of a new infrared absorption peak, also accompanied by huge charge pileup at the interparticle junction, if initial interparticle-contact is made at a single point. This new mode is distinctly different from the lowest mode of the separated dimer. When the junction is made by contact between flat surfaces, charge at the junction is neutralized and mode evolution is continuous through contact. The calculated singular response explains recent experiments on metallic nanoparticle dimers and is relevant in the design of nanoparticle-based sensors and plasmon circuits.

Subfields: Atomic and Molecular Physics, and Optics, Biomedical Engineering, Electronic, Optical and Magnetic Materials

View Paper: https://www.semanticscholar.org/paper/ce270349fb5803f7d3b1997cbf46aaf4e69875d8

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Citations in the corpus

Optical excitations in electron microscopy (2009, background): “For example, the singular transition in the response of touching and non-touching particle dimers (Romero et al., 2006) has already prompted EELS measurements (Chu et al., 2009; N’Gom et al., 2008), although a comprehensive experimental study of this transition is still pending.”
Colloquium: Light scattering by particle and hole arrays (2007, background): “…1983; van de Hulst, 1981) that is being continued by hot topics such as for example novel near-field effects in the coupling of metallic nanoparticle arrays (Krenn et al., 1999) and strong inter-particle interactions in dimers (Atay et al., 2004; Nordlander et al., 2004; Romero et al., 2006).”
Graphene plasmon waveguiding and hybridization in individual and paired nanoribbons. (2012, background): “between the touching and nontouching regimes, unlike what happens in sphere dimers.(48) The third and”
Plasmonic Laser Antennas and Related Devices (2008, background): “distribution present in the nanorod [82].”
Morphology evolution of gold nanoparticles as function of time, temperature, and Au(III)/sodium ascorbate molar ratio (2015, background): “…two-peaks Vis absorption, towards more symmetrical (spherical) particles (Pallavicini et al. 2011; Guerrero-Martı́nez et al. 2011; Mazzucco et al. 2011; Ringe et al. 2012; Henry et al. 2011; Romero et al. 2006; Lu et al. 2009; Van de Broek et al. 2011; Compton and Osterloh 2007; Kumar et al. 2008).”
Blueshift of the surface plasmon resonance in silver nanoparticles studied with EELS (2012, background): “, when the wavelength of the exciting electromagnetic wave considerably exceeds the dimensions of the structure, the local-response Drude theory predicts that the resonance energy of localized SPs is independent of the size of the nanostructure [ 4 ], and that the field enhancement created in the ga”