Application of the coupled classical oscillators model to the Fano resonance build-up in a plasmonic nanosystem

TL;DR

This paper models the excitation dynamics of Fano resonance in plasmonic nanosystems using coupled classical oscillators, providing exact solutions and methods for experimental measurement, with applications to quantum dot and nanoparticle systems.

Contribution

It introduces an exact classical oscillator model with damping for Fano resonance build-up and demonstrates its applicability to nanoscale systems with ultrafast laser pulses.

Findings

Exact solution for damped oscillator model of Fano resonance

Universal response to ultra-wideband pulses

Methods for experimental characterization of resonance build-up

Abstract

We study the excitation dynamics of Fano resonance within the classical model framework of two linear coupled oscillators. An exact solution for the model with a damped harmonic force is obtained. The details of growth a Fano profile under the harmonic excitation is shown. For incident ultra-wideband pulse, the reaction of a system becomes universal and coincides with the time-dependent response function. The results of numerical calculations clarify two alternative ways for experimental measurement of the complete characteristics of a system: direct observation of the system response to a monochromatic force by frequency scanning or recording of time-dependent response to the delta-pulse. As a specific example, time-dependent excitation in a system consisting of a quantum dot and a metal nanoparticle is calculated. Then it is shown the applicability of the extended model of damped oscillators with radiative correction to describe the build-up a plasmon Fano resonance in a scattering of a femtosecond laser pulse by nanoantenna.