title: Longitudinal and transverse coupling in infrared gold nanoantenna arrays: long range versus short range interaction regimes.
abstract: 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 dx and dy in longitudinal and transverse direction, respectively, we experimentally studied the optical extinction spectra for rectangularly ordered lithographic gold nanorod arrays on silicon wafers. For small dy, 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 dx does only marginally broaden the resonance. Our findings set a path for optimum design of rectangular nanorod lattices for surface enhanced infrared spectroscopy.
authors.affiliation: Kirchhoff Institute for Physics, University of Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany. dweber@kip.uni-heidelberg.de
authors.forename: Daniel
authors.initials: D
authors.lastname: Weber
authors.forename: Pablo
authors.initials: P
authors.lastname: Albella
authors.forename: Pablo
authors.initials: P
authors.lastname: Alonso-González
authors.forename: Frank
authors.initials: F
authors.lastname: Neubrech
authors.forename: Han
authors.initials: H
authors.lastname: Gui
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Nagao
authors.forename: Rainer
authors.initials: R
authors.lastname: Hillenbrand
authors.forename: Javier
authors.initials: J
authors.lastname: Aizpurua
authors.forename: Annemarie
authors.initials: A
authors.lastname: Pucci
mesh_terms: D003198:Computer Simulation; D004581:Electronics; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D008670:Metals / Q000737:chemistry; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008962:Models, Theoretical; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D055095:Optics and Photonics; D011846:Radio Waves; D013055:Spectrophotometry, Infrared / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D020349:Surface Plasmon Resonance
chemical_list: D008670:Metals; D006046:Gold