SOFI for Plasmonics: Extracting Near-field Intensity in the Far-Field at High Density

TL;DR

This paper introduces SOFI-COFIBINS, a superresolution technique combining blinking statistics and SOFI to accurately measure near-field intensities in plasmonic systems, even at high emitter densities.

Contribution

It extends the COFIBINS method to high densities using SOFI, enabling precise near-field intensity extraction near metallic surfaces.

Findings

SOFI-COFIBINS accurately matches average fluorescence intensity.

The method effectively probes emitters near metallic surfaces.

Demonstrated with surface plasmon polaritons.

Abstract

Unlike normal fluorescent methods that use the intensity as a direct measurement of the localized enhanced field, we use blinking statistics of quantum dots (QDs). We have already shown that blinking gives a more accurate characterization of the near-field. When an emitter is situated close to a metallic surface, non-radiative pathways are opened up, leading to quenching of the exciton. Blinking statistics, however, is only minimally affected by quenching, and therefore can be used to probe emitters in close proximity to metallic surfaces. We have expanded our method (COFIBINS) to high densities using superresolution technique SOFI. A proof of principle for SOFI-COFIBINS is demonstrated with a defocused point spread function. The method is then applied to surface plasmon polaritons. SOFI-COFIBINS shows excellent agreement with the average fluorescence intensity.