Super-resolved imaging for nanophotonics

In addition to applications of super-resolved imaging to cellular environments, we are also interested in its use in nanophotonics. We have developed a new method for studying light-matter interactions at the nanometric scale using fluorescent molecules in the presence of resonant nanostructures. The method, dubbed smFLIM (single-molecule fluorescence lifetime imaging) cleverly combines the super-localization of photoactivatable molecules with the simultaneous measurement of their lifetime, whose inverse is proportional to electromagnetic local density of states (EM-LDOS) (figure below). In this way, we were able to measure super-resolved EM-LDOS maps around photonic nanostructures. We have demonstrated a spatial resolution of the order of tens of nm in EM-LDOS images measured on plasmonic nanostructures, and this without any scanning probe [Bouchet et al., Optica 2019][Blanquer et al., ACS Phot. 2020]. This is an important breakthrough, as it demonstrates that it is possible to use the super-resolution methods generally used in cell biology to image plasmonic nanostructures [Koenderink et al., Nanophot. 2021].

Principle of smFLIM imaging combining super-resolved imaging and fluorescence lifetime imaging (left) and application to the study of lifetime changes for single molecules coupled with a silver nanowire (right).