# Unveiling Exciton‐Plasmon Polariton Coupling Regions via Polarization‐Enhanced Optical Nanoscopy

## TL;DR

A new microscopy technique improves nanoscale imaging accuracy by using polarization modulation, enabling clearer visualization of exciton-plasmon interactions.

## Contribution

A novel polarization-enhanced SMLM technique is introduced, achieving 16-fold higher localization accuracy and enabling room-temperature exciton-plasmon coupling visualization.

## Key findings

- P-SMLM provides a 16-fold improvement in localization accuracy under low signal-to-noise conditions.
- The technique enables direct visualization of exciton-plasmon polariton coupling regions at room temperature.
- Dynamic polarization modulation enhances point spread function localization accuracy with fewer image frames.

## Abstract

Nanoscale accuracy in single‐molecule localization is a crucial function in wide‐field super‐resolution optical microscopy by surpassing the diffraction limit. However, achieving high localization accuracy remains a challenge due to limitations in the signal‐to‐noise ratio and the complexity of molecular environments. In this study, a novel polarization‐enhanced single‐molecule localization microscopy (P‐SMLM) technique is introduced, incorporating dynamic polarization modulation to enhance the localization accuracy significantly. By modulating the polarization state of the excitation light, the technique leverages molecular sparsity, enabling more precise position determination. A 16 fold improvement in localization accuracy is shown experimentally compared to conventional methods, particularly under low signal‐to‐noise conditions. Moreover, the P‐SMLM enables direct visualization of exciton‐plasmon polariton coupling regions at room temperature. This findings highlight the potential of polarization modulation as a versatile tool for advancing single‐molecule localization microscopy (SMLM) accuracy and its applicability in diverse scientific and technological fields.

Polarization‐enhanced single‐molecule localization microscopy, utilizing a liquid crystal variable retarder (LCVR), actively controls the on‐off intensity modulation of fluorophores. This active intensity modulation improves the localization accuracy of the point spread function (PSF), enabling high‐contrast super‐resolution imaging with significantly fewer image frames. Polarization‐modulated super‐resolution imaging reveals the spatial scale at which exciton–plasmon polariton coupling occurs.