Fanolike resonance due to plasmon excitation in linear chains of metal bumps

Abstract

We report the transmission anomaly in a modified slit grating, which is dressed, on the slit sidewalls, with the linear chains of metal bumps. An asymmetric lineshape, which is characteristic of the Fano resonance, has been found in a narrow frequency range of the spectrum. The effect can be attributed to the interference between nonresonant background transmission and resonant plasmonic wave excitation in the linear chains. The dispersion of chain plasmon mode has been suggested, enabling the dynamic tuning of spectral position of the Fano effect.

Fano resonance in novel plasmonic nanostructures

“… investigated the coupling between localized particle plasmons and optical waveguide modes, which leads to the appearance of a Fano signature in transmission spectra. But the coupling between narrowband waveguide resonance and other additional generated resonances, such as Fabry–Pérot (FP) microcavity resonance or additional modes arising from the chains of metal bumps on slit sidewalls as the contributing factor of FR generation in gratings, is still a subject of debate.…”

“…It has been evaluated that complex and hybrid structures can fulfill the FR requirement for bright and dark modes hybridization as well. For instance, a simple combination of a cross‐shaped structure and a nanobar can provide a clear evidence that once the energy of a dark mode approaches the energy of the bright mode, the FR can be observed as a characteristic asymmetric lineshape .…”

Fano resonances in THz metamaterials composed of continuous metallic wires and split ring resonators

“…Analogs of EIT effects have also been obtained in photonic crystals [7], and plasmonic structures [8]. Over the past several years Fano resonances have been observed in a number of plasmonic nanostructures [9][10][11][12][13][14], metamaterials [15][16][17], metasurfaces [18,19], and nanoclusters including different number of nanoparticles [20][21][22][23][24][25][26][27]. Due to their narrow bandwidth and highly asymmetric lineshape, Fano resonances can be utilized in applications such as biosensors [28], plasmonic rulers [29], slow light [30], plasmonic switch [31], and modulators [32], etc.…”

“…Figure 3(a) shows the simulation results of both transmission and absorption spectra. The frequency of the absorption peak corresponds to the exact frequency of the Fano resonance which lies between the transmission peak and dip [19]. On the curve of the transmission spectrum, we marked three frequency positions with different colored dots which correspond to transmission peak, Fano resonance, and transmission dip, respectively.…”

Tuning asymmetry parameter of Fano resonance of spoof surface plasmons by modes coupling

“…Generally, the Fano resonance comes from the interference between a continuum radiative waves and a discrete non-radiative state, which has been demonstrated in many physical systems. 14 In the realm of plasmonics, both symmetrical 22,23 and asymmetrical 16,24 structures are shown to exhibit pronounced Fano line shapes. The q value can be influenced by several factors such as geometrical configuration, 25 refractive index of materials, 18 temperature, 20 and so on.…”