Mapping Local Surface Plasmon Modes in a Nanoplasmonic Trimer Using Cathodoluminescence in the Scanning Electron...

Area of Science:

• Nanoscience and Nanotechnology
• Plasmonics
• Materials Science

Background:

• Local surface plasmon modes in metallic nanostructures exhibit unique optical properties.
• Understanding plasmon excitation in complex nanostructures is crucial for developing new optical devices.

Purpose of the Study:

• To map the excitability of local surface plasmon modes in radial gold nanorod trimers.
• To investigate the effect of structural asymmetry on plasmon resonance excitation.

Main Methods:

• Utilized hyperspectral cathodoluminescence (CL) microscopy in a scanning electron microscope.
• Analyzed plasmon resonance excitation in both symmetric and asymmetric gold nanorod trimers.

Main Results:

• In symmetric trimers, plasmon resonances were most effectively excited at the ends of individual nanorods.
• Structural asymmetry broke the degeneracy of dipole modes, altering the excitability of transverse dipole modes.
• Demonstrated the capability of CL microscopy for interrogating individual nanophotonic structures.

Conclusions:

• Hyperspectral CL microscopy is a powerful tool for characterizing plasmonic behavior in nanostructures.
• Structural modifications, such as asymmetry, significantly influence plasmon mode excitability.
• This technique complements electron energy loss spectroscopy and optical microscopy for nanophotonic analysis.