Development of UV-visible multiple-angle incidence resolution spectrometry and application study of anisotropic surface plasmon excitation in a silver thin film on a glass substrate.
Multiple-angle incidence resolution spectrometry (MAIRS) that was originally developed in an infrared region for analysis of molecular orientation in a thin film on a substrate has been extended to develop a novel UV-visible spectrometry. The new technique, named Vis-MAIRS, has been employed for analysis of anisotropic surface plasmon excitation in a silver thin film with a thickness of 5 nm deposited on a glass slide. The Vis-MAIRS spectra yield two spectra at a time, which correspond to absorption spectra whose transition moments are parallel and perpendicular to the film surface. The two spectra of the silver thin film were largely different from each other in shape, which strongly suggested that the silver nanoparticles in the thin film were in an ellipsoidal shape. In addition, absorption due to long-range surface plasmon propagation across the nanoparticles aligned parallel to the film surface, which is a result of the dipole or quadruple couplings of plasmon in each particle, was clearly monitored for the first time in the Vis-MAIRS spectra. In this manner, Vis-MAIRS is expected to be a useful tool to study aggregates of metal nanoparticles in a film.
Hasegawa
Takeshi
T
Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan. hasegawa@chem.titech.ac.jp
Itoh
Yuki
Y
Kasuya
Akiyoshi
A