Geometric interpretations for resonances of plasmonic nanoparticles

Area of Science:

• Plasmonics
• Nanophotonics
• Condensed Matter Physics

Background:

• Plasmonics research is divided into surface plasmon polaritons (SPPs) in waveguides and localized surface plasmons (LSPs) on particles.
• These two areas have historically progressed independently, with limited cross-disciplinary investigation.

Purpose of the Study:

• To establish a theoretical connection between SPPs and LSPs.
• To explain anomalous scattering phenomena in plasmonic nanoparticles using a unified model.
• To demonstrate geometric tuning for maximizing light absorption in localized surface plasmons.

Main Methods:

• Interpreting localized surface plasmons (LSPs) through a Bohr model-based geometric perspective.
• Utilizing surface plasmon polaritons (SPPs) as a foundation for the geometric model.
• Analyzing scattering features and resonance properties of plasmonic nanoparticles.

Main Results:

• A unified geometric model connecting SPPs and LSPs was established.
• Anomalous scattering features, including higher-order modes at lower frequencies and size-dependent blueshift, were explained.
• Multiple electric resonances and their origin from backward SPP modes and multiple dispersion bands were elucidated.
• Maximized single-channel absorption limits for LSP resonances were demonstrated through geometric tuning.

Conclusions:

• The geometric model provides a unified framework for understanding plasmonic phenomena.
• Geometric manipulation offers precise control over light absorption and scattering in plasmonic systems.
• This work bridges the gap between waveguide and particle-based plasmonics, opening new avenues for research and applications.