  Herein, we report sub-wavelength propagation and directional out-coupling of
whispering gallery modes (WGMs) of a fluorescent silica microsphere resonator
mediated via plasmon polaritons in a single crystalline silver nanowire.
Fluorescent spectral signatures of emission from the nanowire ends confirm
efficient guiding of WGMs via nanowire plasmons. By employing Fourier plane
optical microscopy, we reveal and quantify the directional fluorescence
emission of WGMs from the ends of the nanowire. Given that the discussed
geometry is self-assembled from a solution-phase, our results will find
relevance in WGM-based soft-photonic platforms including miniaturized optical
resonators and couplers.

Optics;Mesoscale and Nanoscale Physics;Soft Condensed Matter;Applied Physics