Surface-plasmon-mediated single-molecule fluorescence through a thin metallic film

Area of Science:

• Optics and Photonics
• Surface Science
• Spectroscopy

Background:

• Single-molecule fluorescence is a powerful tool for nanoscale investigations.
• Metal nanoparticles and films can influence light-matter interactions.
• Surface plasmons offer unique optical properties for enhancing fluorescence.

Purpose of the Study:

• To investigate the excitation and detection of single-molecule fluorescence near a thin gold film.
• To understand the role of surface plasmons in fluorescence enhancement.
• To quantify the effect of the gold film on photon detection.

Main Methods:

• Utilized an epi-illumination scanning confocal microscope.
• Performed experiments with single molecules in close proximity to a thin gold film.
• Conducted theoretical analysis of the fluorescence signal.

Main Results:

• Demonstrated effective excitation and detection of single-molecule fluorescence through a gold film.
• Confirmed that both excitation and emission are mediated by surface plasmons.
• Observed a significant enhancement in detectable photons from molecules perpendicular to the film.

Conclusions:

• Thin gold films can effectively enhance single-molecule fluorescence.
• Surface plasmon excitation and emission are key mechanisms for this enhancement.
• The presence of metal significantly increases the number of detectable photons.