Electromagnetic enhancement generated by Ap term of cavity quantum electrodynamics demonstrated by single coupled systems between plasmon and molecular exciton

Abstract

In non-relativistic quantum electrodynamics, an electromagnetic (EM) interaction between a photon and a molecular exciton can be expressed by a Ap term and A^2 term, where A and p are the operators of the vector potential of the EM field and the momentum of the exciton, respectively. We developed a method for investigating the contribution of the Ap and A^2 terms to EM enhancement, which occurs in coupled systems composed of a plasmon polariton and a molecular exciton. The spectral shapes of the Ap and A^2 terms terms, and the EM enhancement were experimentally obtained from absorption, Rayleigh scattering, and ultrafast surface enhanced fluorescence (ultrafast SEF) of the systems, respectively. The relationships between them reveal that the absorption spectra correctly reproduce EM enhancement, indicating that ultrafast SEF can be described as a two-step process using the Ap term. Furthermore, we demonstrate that the origin of spectral deviation between Rayleigh scattering and EM enhancement is subradiant plasmon resonance, which spectra are visualized in the absorption not in Rayleigh scattering, with numerical calculation based on electromagnetism.

arXiv comment31 pages, 5 figures

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Cited by in corpus (4)

• Electromagnetic enhancement of one-dimensional plasmonic hotspots along silver nanowire dimer examined by ultrafast surface enhanced fluorescence
• Plasmon-enhanced two photon excited emission from edges of one-dimensional plasmonic hotspots with continuous-wave laser excitation
• Ultrabroad resonance of localized plasmon on a nanoparticle coupled with surface plasmon on a nanowire enabling two-photon excited emission via continuous-wave laser
• Electromagnetic coupling between subradiant plasmons and dye molecular excitons analyzed by spectral changes in ultrafast surface-enhanced fluorescence