Optical properties of strongly coupled 2D trimer and 3D tetramer plasmonic structures

We present DNA-directed self assembly of two-dimensional (2D) trimer and three-dimensional (3D) symmetric tetramer. Polarized scattering spectra are investigated to elucidate the coupled plasmon modes in each cluster, which are compared with Finite Element Method (FEM) modeling. We conclude that drastically enhanced local fields are produced within the interparticle gaps. Even interestingly, the symmetric clusters can exhibit polarization-independent characteristics, and Fano resonances are generated when the symmetry is broken.