局在プラズモン場制御による超解像光トラッピング

抄録

We introduce a novel technique for the quantitative analysis of plasmonic trapping potentials experienced by a nanometer-sized particle. Our experimental results show that these potentials have nanoscale spatial structures that reflect the near-field landscape of the metal nanostructure. The trap stiffness of plasmonic trapping can be enhanced by three orders of magnitude compared to conventional far-field trapping. We also demonstrated super-resolution optical trapping by observing double potential wells with 80-nm separation, which was realized by a gold double-nonogap structure. In addition, we analyzed the nanoscale spatial profiles of plasmonic fields within a nanogap, which exhibit complicated fine structures created by the constructive and destructive interferences of dipolar, quadrupolar, and higher-order multipolar plasmonic modes. The nanoprofile can be drastically changed by controlling the excitation optical system, which is applicable to the dynamic nanomanipulation of single molecules and molecular assemblies.