Manipulation of the dephasing time by strong coupling between localized and propagating surface plasmon modes

Jinghuan Yang,Kosei Ueno,Hiroaki Misawa,Quan Sun,Tomoya Oshikiri,Xu Shi,Qihuang Gong

doi:10.1038/s41467-018-07356-x

Abstract

Strong coupling between two resonance modes leads to the formation of new hybrid modes exhibiting disparate characteristics owing to the reversible exchange of information between different uncoupled modes. Here, we realize the strong coupling between the localized surface plasmon resonance and surface plasmon polariton Bloch wave using multilayer nanostructures. An anticrossing behavior with a splitting energy of 144 meV can be observed from the far-field spectra. More importantly, we investigate the near-field properties in both the frequency and time domains using photoemission electron microscopy. In the frequency domain, the near-field spectra visually demonstrate normal-mode splitting and display the extent of coupling. Importantly, the variation of the dephasing time of the hybrid modes against the detuning is observed directly in the time domain. These findings signify the evolution of the dissipation and the exchange of information in plasmonic strong coupling systems and pave the way to manipulate the dephasing time of plasmon modes, which can benefit many applications of plasmonics.

Highlights

Strong coupling between two resonance modes leads to the formation of new hybrid modes exhibiting disparate characteristics owing to the reversible exchange of information between different uncoupled modes
As the detuning changes, the line width evolves from large to small and from small to large, which signifies the evolution of the proportion of the Localized surface plasmon resonances (LSPRs) mode and the surface plasmon polaritons (SPPs)-Bloch wave in the coupled modes from the perspective of the far-field spectra
We have demonstrated the strong coupling between the LSPR mode and SPP-Bloch wave based on the farfield spectra with the normal-mode splitting of 144 meV

Summary

Introduction

Strong coupling between two resonance modes leads to the formation of new hybrid modes exhibiting disparate characteristics owing to the reversible exchange of information between different uncoupled modes. The variation of the dephasing time of the hybrid modes against the detuning is observed directly in the time domain These findings signify the evolution of the dissipation and the exchange of information in plasmonic strong coupling systems and pave the way to manipulate the dephasing time of plasmon modes, which can benefit many applications of plasmonics. An anticrossing behavior observed in the far-field spectra verifies the strong coupling between the LSPR mode and SPP-Bloch wave. The near-field enhancement of the hybrid modes is still maintained and is even higher than that of the bare LSPR mode These findings greatly enhance our understanding of the strong coupling between different plasmon modes and can benefit many plasmonic applications

Methods

Results

Conclusion