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

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 one to probe light-matter interactions at a subwavelength resolution, which remains experimentally challenging. Here, we introduce an approach to perform super-resolved fluorescence lifetime measurements on samples that are densely labeled with photo-activatable fluorescent molecules. The simultaneous measurement of the position and the decay rate of the molecules provides 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 Cramer-Rao analysis that the proposed experimental setup enables a single-molecule localization precision of 6 nm. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement