Multipolar plasmon resonances in individual ag nanorice

Area of Science:

• Plasmonics and Nanophotonics
• Optical Spectroscopy of Nanomaterials

Background:

• Surface plasmon resonance (SPR) in metallic nanoparticles is crucial for sensing and optics.
• Understanding high-order SPR modes in complex nanostructures like nanorice is essential for advanced applications.
• Individual particle analysis offers detailed insights beyond ensemble measurements.

Purpose of the Study:

• To investigate the optical excitation of high-order surface plasmon resonance (SPR) modes in individual silver nanorice particles.
• To analyze the influence of particle geometry and illumination conditions on SPR modes.
• To correlate experimental observations with theoretical models.

Main Methods:

• Utilized dark-field scattering spectroscopy for optical excitation and analysis of individual Ag nanorice particles.
• Employed model calculations based on the boundary element method (BEM) for theoretical analysis.
• Investigated the effect of oblique illumination to break symmetry and reveal specific resonance modes.

Main Results:

• Successfully observed high-order surface plasmon resonance modes in individual silver nanorice particles.
• Demonstrated that oblique illumination enables the observation of even-order resonance modes due to symmetry breaking.
• Found a consistent redshift in all resonance peaks with increasing particle length.

Conclusions:

• The study elucidates the excitation mechanisms of high-order SPR modes in nanorice structures.
• Particle length is a critical parameter controlling the spectral position of SPR modes.
• Asymmetric illumination is a key technique for accessing specific plasmonic modes in non-ideal geometries.