Analysis of Dynamics of Excitation and Dephasing of Plasmon Resonance Modes in Nanoparticles

A novel theoretical approach to the dynamics analysis of excitation and dephasing of plasmon modes in nanoparticles is presented. This approach is based on the biorthogonal plasmon mode expansion, and it leads to the predictions of time dynamics of excitation of specific plasmon modes as well as their steady state amplitude and their decay. Temporal characteristics of plasmon modes in nanoparticles are expressed in terms of their shapes, permittivity dispersion relations, and excitation conditions. In the case of the Drude model, analytical expressions for time-dynamics of plasmon modes are obtained.

Figure 1

Dynamics of plasmon resonances for Au nanorings (height 60 nm, inner radius 55 nm, outer radius 65 nm) on a glass substrate (${ϵ}_s=2.25$) computed for the resonance wavelength 1102 nm (see 15) by using (a) Drude model ($\gamma =1.0753\times {10}^{14}{\mathrm{s}}^{-1}$ [13]) and (b) Au dispersion relation from 13.

Figure 2

Dynamics of plasmon resonances for Au cylinders (height 14 nm, diameter 126 nm) on a glass substrate (${ϵ}_s=2.25$) computed for the resonance wavelength 774 nm (see 2). The Au dispersion relation from 13 have been used in computations.

Figure 3

Envelop of the calculated third order ACF (filled circles) superimpose on the measured third order ACF (solid line) from 2 for Au cylinders on a glass substrate at wavelength 774 nm (maximum is normalized to 32).

Figure 4

The calculated second-order ACF superimpose on the envelop of measured second-order ACF from 6 for noncentrosymmetric $L$-shape Au nanoparticles (height 21 nm, arm length 150 nm, arm width 75 nm) on a tantalum-dioxide substrate (${ϵ}_s=4.33$) at wavelength 838 nm (maximum is normalized to 8).