Remote two-dimensional nanometric localization of molecules by the analysis of fluorescence coupled to guided surface plasmons

Abstract

The coupling between fluorescent emitters and the metal nanowire (NW) can excite the guided surface plasmon polaritons (SPPs) on the NW and can be exploited to extract the characteristic parameters of fluorescent emitters. Based on the coupling of molecular fluorescence to the guided SPPs on the silver NWs, a two-dimensional localization of molecules with nanometric accuracy was achieved. The SPPs coupled from molecular fluorescence propagate along the silver NWs and are collected after scattering at the two remote ends of the NWs. By analyzing the fluorescence lifetime of the collected scattered field of SPPs, the localization of molecules along the radial direction of the NW was realized with a localization accuracy better than 5 nm. By analyzing the intensity ratio of the scattered fields of the bi-directionally propagating SPPs collected at the two remote ends of the NW, the localization of molecules along the axial direction of the NW was realized, with a localization accuracy better than 0.28 times the fluorescence wavelength. The scheme proposed in this paper can be a promising step towards a complete on-chip super-resolution localization of fluorescent molecules.