Achievement

Liane Slaughter investigated near-field plasmon coupling between closely spaced nanoparticles (NPs). Dark-field scattering experiments on self-assembled rings of gold NPs showed that the collective plasmon along a chain of 40 nm NPs closely resembles that of a gold nanorod nearly one micron in length. Spectra of ring segments revealed additional modes which were significantly red-shifted from the single NP mode at 550 nm and highly polarized along the ring circumference. Using a patterned substrate, they correlated structural information from SEM images with scattering images and found that the spectra remained mostly insensitive to the local disorder of the nanoparticle arrangement, i.e. the spectra were unaffected by gaps and variations in ring thickness. This project will help establish design parameters for creating structures to sustain coupled plasmon resonances, potentially allowing us to develop light-propagating components unbound by the diffraction limit of light.