A classical description of subnanometer resolution by atomic features in metallic structures.

Area of Science:

• Plasmonics
• Nanotechnology
• Spectroscopy

Background:

• Plasmonic-enhanced probe spectroscopy has demonstrated sub-nanometer resolution.
• This resolution exceeds explanations based on nanoparticle radii alone.

Purpose of the Study:

• Investigate the impact of atomic-scale defects on plasmonic probe tips.
• Determine how these defects influence spatial resolution and field localization.

Main Methods:

• Analysis of crystalline metallic nanoparticles using transmission electron microscopy (TEM).
• Electrodynamic calculations using the Finite Element Method (FEM).
• Simulations under resonant and non-resonant illumination conditions.

Main Results:

• Atomic features like edge and corner sites are present on nanoparticles.
• These features critically affect lateral spatial resolution and field localization.
• Sub-nanometer resolution is achievable with atomic-scale defects.

Conclusions:

• Atomic-scale defects on plasmonic probes are key to achieving ultra-high spatial resolution.
• Understanding these defects refines the limits of plasmon-enhanced spectroscopy and microscopy.
• Sub-nanometer resolution is attainable for practical applications in nanoscale imaging.