Near-field imaging of surface plasmon on gold nano-dots fabricated by scanning probe lithography

We obtained scanning near-field optical microscopy images to study the excitation of surface plasmons on metallic dots fabricated using scanning probe lithography. Gold nano-dots were fabricated by applying electric voltages to conducting probes installed in an atomic force microscope using the mechanism of field-induced diffusion and nano-oxidation plus Au-coating. High spatial resolution of scanning near-field optical microscopy revealed a 'bifold' pattern of surface plasmon mode on fabricated Au dots in the polarization direction of incident light. We found that scanning near-field optical microscopy imaging combined with scanning probe lithography is able to provide a systematic study of surface plasmon excitation on nano-metallic structures.