Probing near-field light-matter interactions with single-molecule lifetime imaging

TL;DR

This paper introduces a super-resolution fluorescence lifetime imaging technique to probe near-field light-matter interactions at the nanoscale, enabling precise localization and LDOS mapping around nanostructures.

Contribution

The authors develop a method for super-resolved lifetime measurements of densely labeled molecules, allowing direct nanoscale LDOS mapping with high localization precision.

Findings

Demonstrated LDOS variations near a silver nanowire

Achieved 6 nm localization precision for single molecules

Validated the technique's effectiveness through experimental results

Abstract

Nanophotonics offers a promising range of applications spanning from the development of efficient solar cells to quantum communications and biosensing. However, the ability to efficiently couple fluorescent emitters with nanostructured materials requires to probe light-matter interactions at subwavelength resolution, which remains experimentally challenging. Here, we introduce an approach to perform super-resolved fluorescence lifetime measurements on samples that are densely labelled with photo-activatable fluorescent molecules. The simultaneous measurement of the position and the decay rate of the molecules provides a direct access to the local density of states (LDOS) at the nanoscale. We experimentally demonstrate the performance of the technique by studying the LDOS variations induced in the near field of a silver nanowire, and we show via a Cram\'er-Rao analysis that the proposed experimental setup enables a single-molecule localisation precision of 6 nm.