[20a-S622-1~11] 3.12 Nanoscale optical science and near-field optics

[20a-S622-6] Time-domain observation of dephasing process of multipolar plasmon in a gold nanodisk

〇Yoshio Nishiyama¹, Hiromi Okamoto^1,2 (1.IMS, 2.Sokendai)

Keywords:plasmon,dephasing,near-field optical microscpy

We investigated dephasing process of multipolar plasmon in a gold nanodisk based on time-domain observation using ultrafast near-field optical microscopy. The excitation of the multipolar plasmon showed different spatial feature of the near-field optical image from that for the dipolar mode, and the time-resolved signal behavior was also different. Dephasing times of the plasmon resonances evaluated from the time-resolved observation demonstrates that the plasmon lifetime of the multipolar mode is longer than that that of the dipolar mode.