Super-resolution imaging of SERS hot spots

Area of Science:

• Plasmonics
• Nanotechnology
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) relies on localized electromagnetic field enhancements (hot spots) near plasmonic nanostructures.
• Far-field optical microscopy is limited by diffraction, preventing direct resolution of SERS hot spot properties.
• Single-molecule emission coupling to plasmon modes is crucial for SERS enhancement.

Purpose of the Study:

• To review the principles of super-resolution imaging for SERS hot spots.
• To explain how single molecules probe local electromagnetic field enhancements.
• To highlight new methods for understanding SERS hot spot characteristics.

Main Methods:

• Utilizing super-resolution imaging techniques to determine emitter positions with sub-5 nm precision.
• Applying model functions, such as 2D Gaussians and dipole-based functions, to emission data.
• Performing spectrally- and spatially-resolved measurements of molecule-plasmon interactions.

Main Results:

• Demonstrated super-resolution imaging of SERS hot spots using single molecules.
• Quantified emitter positions with precision better than 5 nm.
• Introduced advanced fitting functions and measurement strategies for enhanced analysis.

Conclusions:

• Super-resolution imaging provides unprecedented insight into SERS hot spots.
• The properties of SERS hot spots are defined by both the molecule and the plasmonic substrate.
• New methodologies offer deeper understanding of localized electromagnetic field enhancements.