Longitudinal and transverse coupling in infrared gold nanoantenna arrays: long range versus short range interaction regimes

Daniel Weber, Pablo Albella, Pablo Alonso-González, Frank Neubrech, Han Gui, Tadaaki Nagao, Rainer Hillenbrand, Javier Aizpurua, Annemarie Pucci
2011 Optics Express  
Interaction between micrometer-long nanoantennas within an array considerably modifies the plasmonic resonant behaviour; for fundamental resonances in the infrared already at micrometer distances. In order to get systematic knowledge on the relationship between infrared plasmonic resonances and separation distances d x and d y in longitudinal and transverse direction, respectively, we experimentally studied the optical extinction spectra for rectangularly ordered lithographic gold nanorod
more » ... on silicon wafers. For small d y , strong broadening of resonances and strongly decreased values of far-field extinction are detected which come along with a decreased near-field intensity, as indicated by near-field amplitude maps of the interacting nanoantennas. In contrast, near-field interaction over small d x does only marginally broaden the resonance. Our findings set a path for optimum design of rectangular nanorod lattices for surface enhanced infrared spectroscopy.
doi:10.1364/oe.19.015047 pmid:21934866 fatcat:ltlathldbjh5pjd5mjptglam2m