Mislocalization in Plasmon-Enhanced Single-Molecule Fluorescence Microscopy as a Dynamical Young’s Interferometer

Mislocalization is a quantitative measure of the inability to locate the positions of individual molecular emitters in plasmon-enhanced super-resolution fluorescence microscopy. It is due to an unfortunate side-effect that scrambles the spatial profile of a molecule’s fluorescence signal when plasmonic nanoantennas are introduced to boost that signal. In this article, we present an understanding of the mislocalization problem in plasmon-enhanced super-resolution fluorescence microscopy based upon a simple and intuitive theoretical model. In particular, we derive an analytic expression for mislocalization and demonstrate explicitly how it depends upon both the macroscopic interference of the coherent emission from molecular and plasmonic emitters and the microscopic dynamics of the coupled system. To derive this expression, we draw upon an analogy to the Fano interference problem and show that the spatial asymmetry in the intensity profile can be encapsulated into a single effective parameter that depends ...