Sub-Wavelength Plasmon Polaritons Channeling of Whispering Gallery Modes of Fluorescent Silica Microresonator

TL;DR

This paper demonstrates sub-wavelength guiding and directional out-coupling of whispering gallery modes in a fluorescent silica microsphere resonator using plasmon polaritons in a silver nanowire, advancing miniaturized optical photonic devices.

Contribution

It introduces a novel method for efficient WGM channeling via plasmon polaritons in a self-assembled nanowire-microsphere system, enabling miniaturized photonic applications.

Findings

Efficient guiding of WGMs via nanowire plasmons confirmed by spectral signatures.

Directional fluorescence emission from nanowire ends quantified.

Self-assembled geometry suitable for soft-photonic platforms.

Abstract

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.