Time-dependent transport of a localized surface plasmon through a linear array of metal nanoparticles: Precursor and normal mode contributions

Abstract

We theoretically investigate the time-dependent transport of a localized surface plasmon excitation through a linear array of identical and equidistantly spaced metal nanoparticles. Two different signals propagating through the array are found: one traveling with the group velocity of the surface plasmon polaritons of the system and damped exponentially, and the other running with the speed of light and decaying in a power-law fashion, as x −1 and x −2 for the transversal and longitudinal polarizations, respectively. The latter resembles the Sommerfeld-Brillouin forerunner and has not been identified in previous studies. The contribution of this signal dominates the plasmon transport at large distances. In addition, even though this signal is spread in the propagation direction and has the lateral dimension larger than the wavelength, the field profile close to the chain axis does not change with distance, indicating that this part of the signal is confined to the array.

Topological Phases of Polaritons in a Cavity Waveguide

“…As such, realizing our model of a dipolar chain via the Mie resonances of dielectric nanoparticles is experimentally appealing [22,48,49]. Metallic nanoparticles hosting plasmonic excitations are an alternative platform which correspond to our theory, and which benefits from extensive experimental and theoretical study [50][51][52][53][54][55][56][57][58][59][60][61][62]. In fact, our model is relevant for any system where dipolar interactions are the dominant mechanism, for example microwave arXiv:1907.02013v1 [cond-mat.mes-hall] 3 Jul 2019 helical resonators [63], magnonic microspheres [64], and cold atoms [65].…”

Topological plasmons in dimerized chains of nanoparticles: robustness against long-range quasistatic interactions and retardation effects

“…The regular plasmonic chain has been extensively studied both theoretically [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] and experimentally [32][33][34][35][36][37][38][39]. Crucially, it was noticed theoretically that retardation in the dipole-dipole interaction amongst the LSPs can have a dramatic influence on the plasmonic bandstructure [17-23, 27, 28, 30, 31].…”

Quantum theory of plasmon polaritons in chains of metallic nanoparticles: From near- to far-field coupling regime

“…2] presents a discontinuity, i.e., no roots are found. Taking into account Ohmic losses however leads to a definite root at the intersection [30,56], where the slope of the curve changes drastically to be equal to the slope of the light line, namely c. For larger values of qd, the plasmonic excitation is interacting with photonic modes of higher energy and the normal modes correspond to guided ones, which are immune to radiation damping.…”

“…We also notice that in the transverse case the real roots, corresponding to the lower band, are difficult to find for values of qd 1. The problem is even more stringent using the classical model, where no solutions can be found [20,30].…”

“…On the one hand, linear chains of nanoparticles have been extensively studied over the past through numerous experimental [7][8][9][10][11][12][13] and theoretical [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] works, especially in the near-field regime where propagation is most promising, that is, when the interparticle distances d is such that d λ 0 , λ 0 being the wavelength associated with the dipolar LSP excitation. On the other hand, the far-field regime, with d λ 0 , has been much less studied [32], even if it also has interesting properties.…”