Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 23: Plasmonics and Nanooptics: Light-Matter Interaction, Spectroscopy
O 23.5: Poster
Montag, 7. März 2016, 18:15–20:30, Poster E
Efficiency of Fano resonance in arrangements of nanorods: a comparison study — •Madeleine Nilsen1, Manuel Gonçalves1, Armen Melikyan2, Hayk Minassian3, Taron Makaryan4, and Othmar Marti1 — 1Ulm University - Institute of Experimental Physics, Ulm, Germany — 2Russian-Armenian (Slavonic) University, Yerevan, Armenia — 3Yerevan Physics Institute, Yerevan, Armenia — 4Drexel Nanomaterials Group, Drexel University, Philadelphia, USA
Nanorods allow easy tuning of optical resonances by varying the rod length and aspect ratio. Multipole resonances in rod-like nanoparticles are well separated and have relatively small bandwidths. Thus, assemblies of nanorods have been successfully used for generating Fano resonances.
In rods arranged in dolmen configuration, the dark mode necessary for the destructive interference of the Fano resonance is excited in both parallel rods simultaneously, with anti-symmetric surface charge density. In a H-like configuration of rods, quadrupole dark modes are excited independently in each long rods, resulting although in a mirror anti-symmetric surface charge density. Moreover, the near-field coupling of the H-like structure leads to a more pronounced Fano resonance than in the dolmen. H-like structures assembled in linear arrays with short separation comparing to the wavelength produce further attenuation of the scattering cross-section at the Fano dip.
The optical properties of the coupled nanorods were investigated by finite-element method (FEM). Nanorod structures were fabricated by e-beam lithography (EBL) and focused ion beam milling (FIB).