Fano-like interference of plasmon resonances at a single rod-shaped nanoantenna

López-Tejeira, F.; Paniagua‐Domínguez, Ramón; Rodríguez-Oliveros, Rogelio; Sánchez‐Gil, José A.

doi:10.1088/1367-2630/14/2/023035

Cited by 59 publications

(80 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When two oscillators overlap both spatially and spectrally, both constructive and destructive interferences can be observed [16]. Destructive interference can result in reduced scattering cross sections and generate strongly localized near-fields [17], while constructive interference can result in super-radiant modes with enhanced scattering [12].…”

Section: Introductionmentioning

confidence: 99%

Modal interference in spiky nanoshells

Hastings¹,

Qian²,

Swanglap³

et al. 2015

Opt. Express

View full text Add to dashboard Cite

Near-field enhancement of the electric field by metallic nanostructures is important in non-linear optical applications such as surface enhanced Raman scattering. One approach to producing strong localization of the electric field is to couple a dark, non-radiating plasmonic mode with a broad dipolar resonator that is detectable in the far-field. However, characterizing or predicting the degree of the coupling between these modes for a complicated nanostructure can be quite challenging. Here we develop a robust method to solve the T-matrix, the matrix that predicts the scattered electric fields of the incident light, based on finite-difference time-domain (FDTD) simulations and least square fitting algorithms. This method allows us to simultaneously calculate the T-matrix for a broad spectral range. Using this method, the coupling between the electric dipole and quadrupole modes of spiky nanoshells is evaluated. It is shown that the built-in disorder in the structure of these nanoshells allows for coupling between the dipole modes of various orientations as well as coupling between the dipole and the quadrupole modes. A coupling strength of about 5% between these modes can explain the apparent interference features observed in the single particle scattering spectrum. This effect is experimentally verified by single particle backscattering measurements of spiky nanoshells. The modal interference in disordered spiky nanoshells can explain the origin of the spectrally broad quadrupole resonances that result in strong Quadrupole Enhanced Raman Scattering (QERS) in these nanoparticles.

show abstract

Section: Introductionmentioning

confidence: 99%

Modal interference in spiky nanoshells

Hastings¹,

Qian²,

Swanglap³

et al. 2015

Opt. Express

View full text Add to dashboard Cite

show abstract

“…This phenomenon, characterized by an asymmetric spectral line shape, is known as Fano resonance or Fano interference and mainly arises here from the Q y mode's l = 3 component, as it is also observed for nanorods (α = 180°). 39 The impact of this Fano interference on the angular distribution of the scattering intensity is illustrated in Figure 2. In this figure, simulated (panels a,b) and experimental (panel c) results for the L = 250 nm, α = 120°antenna in Figure 1 are provided, at several wavelengths around the Q y -Fano resonance for y-polarized light.…”

mentioning

confidence: 99%

Unidirectional Side Scattering of Light by a Single-Element Nanoantenna

et al. 2013

View full text Add to dashboard Cite

Unidirectional side scattering of light by a singleelement plasmonic nanoantenna is demonstrated using full-field simulations and back focal plane measurements. We show that the phase and amplitude matching that occurs at the Fano interference between two localized surface plasmon modes in a V-shaped nanoparticle lies at the origin of this effect. A detailed analysis of the V-antenna modeled as a system of two coherent point-dipole sources elucidates the mechanisms that give rise to a tunable experimental directivity as large as 15 dB. The understanding of Fano-based directional scattering opens a way to develop new directional optical antennas for subwavelength color routing and selfreferenced directional sensing. In addition, the directionality of these nanoantennas can increase the detection efficiency of fluorescence and surface enhanced Raman scattering.KEYWORDS: Nanoantenna, surface plasmon resonance, directionality, Fano resonance, side scattering T he interaction of light with metal nanoparticles is largely governed by resonant oscillations of the free electrons at the metal-dielectric interface. These so-called localized surface plasmon resonances (LSPR) can reach frequencies in the visible spectrum, have large extinction cross sections, are very sensitive to the surrounding medium, and lead to deepsubwavelength electromagnetic field confinement and enhancement. Plasmonic resonators, therefore, bring optics into the nanoscale and have already found applications in disease diagnostics and treatment, photovoltaics, and optical communications. 1−7One of the most determinative characteristics of a plasmonic resonator is its shape. It is well-known that the shape determinesto a large extentthe LSPR spectral positions. 8Specific resonator designs, consisting of a single or multiple particles, also allow to control the LSPR quality-factor by scattering loss engineering based on plasmon hybridization, 9 sub-and superradiance, and Fano interference.10−13 Additionally, similar to classical antennas, a proper plasmonic antenna design will impact its directionalitythat is, the ability to direct scattered radiation in a particular direction. Achieving high directivities in combination with a high degree of flexibility for the direction is elementary to devise efficient subwavelength plasmonic transmitters, receivers, and sensors.To obtain directional scattering, constructive and destructive interferences of multiple coherent radiation sources with carefully designed spatial separation and phase differences are required. Directional scattering of a plane wave along its propagation direction has recently been observed in core−shell nanoparticles, 14 as well as in nonmetallic silicon nanospheres. 15The obtained large forward-to-backward scattering ratios were shown to result from interfering dipoles and quadrupoles where retardation of the incident light over the particle volume activates the higher order mode and induces the required phase differences. 16 Higher order modes in a tilted plasmonic nanocup c...

show abstract

“…5.a). Thus, phase toggling takes place as the photon energy is varied through the coupled quadrupole resonance, 55 Placing the two particles at larger distance (black line in Fig 5.b) the coupling is reduced and the extinction spectrum shows a broad peak, resembling to the dipolar excitation of a single particle. If a third particle is located at the center of such dimer, the dipolar mode is only slightly perturbated since the field acting on the central particle at the origin vanishes and the resonance is still broad.…”

Section: Resultsmentioning

confidence: 99%

Dark Modes and Fano Resonances in Plasmonic Clusters Excited by Cylindrical Vector Beams

2012

View full text Add to dashboard Cite

Control of the polarization distribution of light allows tailoring the electromagnetic response of plasmonic particles. By rigorously extending the generalized multiparticle Mie theory, we show that focused cylindrical vector beams (CVB) can be used to efficiently excite dark plasmon modes in nanoparticle clusters. In addition to the small radiative damping and large field enhancement associated to dark modes, excitation with CVB can give place to unusual phenomenology like the formation of electromagnetic cold spots and the generation of Fano resonances in highly symmetric clusters. Overall, the results show the potential of CVB to tailor the plasmonic response of nanoparticle clusters in a unique way.

show abstract

Fano-like interference of plasmon resonances at a single rod-shaped nanoantenna

Cited by 59 publications

References 42 publications

Modal interference in spiky nanoshells

Modal interference in spiky nanoshells

Unidirectional Side Scattering of Light by a Single-Element Nanoantenna

Dark Modes and Fano Resonances in Plasmonic Clusters Excited by Cylindrical Vector Beams

Contact Info

Product

Resources

About