Modal approximation for plasmonic resonators in the time domain: the scalar case.

Area of Science:

• Electromagnetism and Optics
• Computational Physics

Background:

• Understanding electromagnetic scattering from nanoparticles is crucial for optical applications.
• Dispersive material properties and resonant regimes present significant theoretical challenges.

Purpose of the Study:

• To develop a modal approximation for electromagnetic fields scattered by metallic nanoparticles.
• To analyze the behavior of these fields in low-frequency and resonant regimes.
• To validate the approximation through numerical simulations.

Main Methods:

• Defining non-Hermitian modes as perturbations of electro-static modes.
• Obtaining a frequency-domain modal approximation of the scattered field.
• Analyzing the eigenvalues of a singular boundary integral operator.
• Presenting two-dimensional numerical simulations.

Main Results:

• The poles of the modal expansion correspond to eigenvalues in the lower-half complex plane.
• The modal representation provides a highly accurate approximation of the scattered field.
• Numerical simulations confirm the validity of the modal approach.

Conclusions:

• The developed modal representation accurately describes electromagnetic scattering from dispersive metallic nanoparticles.
• This method offers a powerful tool for analyzing nanoparticle optics in resonant regimes.
• The findings have implications for designing optical devices and metamaterials.