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Updated: May 31, 2026
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Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle
Published on: January 3, 2016
Plasmon delocalization onset in finite sized nanostructures
Arash Farhang1, Olivier J F Martin
1Nanophotonics and Metrology Laboratory, Swiss Federal Institute of Technology Lausanne EPFL-STI-NAM, Lausanne, Switzerland. arash.farhang@epfl.ch
Optics Express
|July 1, 2011
Summary
Researchers studied the shift from localized to delocalized surface plasmons in silver nanoparticles of varying lengths. They found that delocalized plasmons emerge from a superposition of standing waves, enabling even short metal films to support them.
Area of Science:
- Plasmonics
- Nanophotonics
- Surface Physics
Background:
- Surface plasmons are collective oscillations of electrons at a metal-dielectric interface.
- Understanding the transition from localized to delocalized plasmon modes is crucial for plasmonic device applications.
Purpose of the Study:
- To investigate the transition from localized to delocalized surface plasmon modes in a single 2D silver nanoparticle as its length increases.
- To analyze the nature of delocalized plasmon modes in finite-sized nanostructures.
Main Methods:
- Fourier analysis of the near-field.
- Simulations of far-field scattering spectra.
- Direct measurement of near-field profiles along and above the nanoparticle.
Main Results:
- The study clearly demonstrates the transition from localized to delocalized plasmon modes with increasing nanoparticle length.
- Delocalized modes in finite rectangular nanoparticles are shown to be superpositions of standing wave plasmon modes.
- Even short metal films were found to support delocalized plasmons that propagate and reflect.
Conclusions:
- The transition to delocalized plasmons is a key phenomenon in finite nanostructures.
- The superposition of standing waves explains the behavior of delocalized plasmons in rectangular nanoparticles.
- This finding has implications for the design of plasmonic devices utilizing wave propagation in short metal films.
