Super-resolution lifetime imaging of single molecules surrounding gold bowtie nanoparticles

Abstract

Interactions between light and matter serve as the basis of many of the technologies weuse, whether it be photon absorption, emission, or other transfers of energy. The quality of these devices is thus inherently limited by the optical properties of their constituents, which are regularly quite lacking in efficiency. Plasmonic nanoparticles serve as a highly versatile and tunable platform for the enhancement of such optical properties when one of these optical transitions occurs in their near-field. However, the near-field nature of these effects has made thorough study and understanding of these mechanisms difficult. Particularly, a study of molecular decay rate enhancement in resonant plasmonic environments on this length scale has only recently been performed, and with limitations on efficiency and resolution. In this dissertation, I describe a new technique that combines super-resolution microscopy with fluorescence lifetime imaging microscopy (FLIM) to study single-molecule decay rate enhancement in a single-measurement, with spatial resolution on the order of 10 nm. Additionally, in the same measurement, we verify the validity of this technique using autocorrelation to confirm that our data indeed originates from individual molecules, avoiding ensemble averaging. This thesis provides further insight into the various mechanisms of plasmon-enhanced emission, decoupled from absorption enhancement, providing a platform for further study of emission mislocalization and the position-dependent prominence of different decay pathways.