[17a-A305-1~9] 3.11 Nanoscale optical science and near-field optics (formerly 3.12)

[17a-A305-6] Examination of AP term of quantum electrodynamics using ultrafast surface-enhanced fluorescence emitted from coupled systems between plasmon and molecular exciton

〇Tamitake Itoh¹, Yuko S. Yamamoto² (1.AIST, 2.JAIST2)

Keywords:plasmon, SERS, QED

In quantum electrodynamics, the interaction between light and matter is described by AP and A² terms. Using the dipole approximation, the AP term corresponds to light absorption and light emission, and the A² term corresponds to light scattering and diffraction. Since the Raman process is described by light absorption and light emission, it is expressed by the product of two AP terms. However, the application of the dipole approximation is needed to be verified because surface-enhanced Raman scattering (SERS) is caused in the nanometer-gap region of gold and silver nanoparticle aggregates by localized electromagnetic (EM) enhancement effects. Therefore, in this study, we derived the spectrum of the EM enhancement factor using SERS emitted from silver nanoparticle dimers with its background light, surface-enhanced ultrafast fluorescenceAs a result, the EM enhancement factor spectrum showed better correlation with the absorption spectrum. This result indicates that SERS and ultrafast fluorescence are caused by the AP term.