Plasmonic nanowires arranged in Fibonacci number chain: Excitation angle-dependent optical properties

Abstract

Herein we numerically study the excitation angle-dependant far-field and near-field optical properties of vertical plasmonic nanowires arranged in an unconventional linear geometry: Fibonacci number chain. The first five numbers in the Fibonacci series (1, 1, 2, 3, 5) were mapped to the size of gold nanowires, and arranged in a linear chain to study their optical interactions, and compared them to conventional chain of vertical gold nanowires. By harnessing the radiative and evanescent coupling regimes in the geometry, we found a systematic variation in the far-field extinction and near-field confinement in the geometries. Our simulation studies revealed enhanced backscattered intensity in the far-field radiation pattern at excitation angles along the chain-length of Fibonacci geometry, which was otherwise absent for conventional chain of plasmonic nanowires. Such angular reconfiguration of optical fields in unconventional linear geometries can be harnessed for tunable on-chip plasmonics.

Adiabatic nanofocusing: spectroscopy, transport and imaging investigation of the nano world

“…Advances in nanotechnology have allowed the realization of photonic nanostructures that spatially confine and enhance the electric field by orders of magnitudes, either in 2D or 3D geometries. There are planar resonant wires [3][4][5], standing conical nanoantennas [5], wire-chains [6,7], hollow cavities [8], nanospheres [9] and hybrid structures [10], all in various ways tunable from the visible to the IR spectral range. Many of them, fabricated on specific substrates, are pinned in a fixed position in space and organized in sets of arrays.…”