Raman Enhancement via Polariton States Produced by Strong Coupling between a Localized Surface Plasmon and Dye Excitons at Metal Nanogaps.
Polarized Raman scattering measurement was carried out using a hybridized system of Ag nanodimer structures and organic dye molecules. Tuning of the localized surface plasmon resonance energy leads to modulation of the hybridized polariton energy. The anticrossing behavior of the polariton energy implies a strong coupling regime with maximum Rabi splitting energy of 0.39 eV. The observation proves the effective Raman enhancement via the excitation of the upper and the lower branches of the hybridized states at the gap of the metal dimer. Maximum Raman enhancement was obtained at an optimized resonant energy between the hybrid states and Raman excitation.
Department of Chemistry, Faculty of Science, Hokkaido University, North 10 West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
Fumika
F
Nagasawa
Department of Chemistry, Faculty of Science, Hokkaido University, North 10 West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
Mai
M
Takase
Department of Chemistry, Faculty of Science, Hokkaido University, North 10 West 8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
Kei
K
Murakoshi
dye exciton; localized surface plasmon resonance; polarized Raman measurement; strong coupling; surface-enhanced Raman scattering