Realizing Anderson localization of surface plasmon polaritons and enhancing their interactions with excitons in 2D disordered nanostructures

Abstract

Surface plasmon polaritons (SPPs) propagating on a metal–dielectric interface suffer from inevitable energy losses originating from metals, especially in a visible regime, which degrades the quality of SPP-based devices. However, if the size of the devices is sufficiently miniaturized, we can thereby limit the propagation length of the signals and effectively circumvent the problems of large propagation losses. Anderson localization is a possible approach to squeeze SPPs. In this Letter, we experimentally demonstrate the Anderson localization of SPPs at optical frequencies in two-dimensional (2D) nanostructures. By increasing the positional disorder of the silver nanohole arrays on a glass substrate, strong 2D localization of SPPs appears with an exponentially decreased electric field, reduced propagation length, and the rapid disappearance of the autocorrelation coefficient. Moreover, we manage to realize the localized SPP-exciton interactions in the 2D disordered silver nanoarrays combined with fluorescent dye molecules. Due to the disorder in the nanoarray, the collected photoluminescence from fluorescent dye molecules is enhanced by over three orders of magnitude compared to that on the silver film without nanostructures. Our study extends Anderson localization of SPPs at the visible regime to 2D disordered systems and provides a unique way to enhance light–matter interaction in SPP-based nanodevices.