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O: Fachverband Oberflächenphysik

O 38: Nano-optics of metallic and semiconducting nanostructures (experiments I)

O 38.10: Talk

Wednesday, March 25, 2009, 17:15–17:30, SCH A216

Observations of selective near-field focusing on three-fold symmetric, mesoscopic surface patterns - measured with PEEM — •Michael Berndt^1,2, Brian Ashall¹, Martin Rohmer³, Christian Schneider³, Martin Aeschlimann³, and Dominic Zerulla¹ — ¹University College Dublin, School of Physics, Belfield, Dublin 4, Ireland — ²MPI of Molecular Cell Biology and Genetics, 01307 Dresden, Germany — ³Technische Universität Kaiserslautern, Fachbereich Physik, 67663 Kaiserslautern, Germany

Optically active, structured surfaces, which provide strong localisation of excitation energies in certain “hot-spots” on their surface are required for many applications.
We examine the modification and polarisation dependence of optical near-fields on the surface of an array of three-fold symmetric, mesoscalic, silver-coated structures produced by e-beam lithography. For mapping the spatially resolved near-fields and examining the influence of polarisation of the excitation light, we use a photoelectron emission microscope (PEEM). We find that the presented structures show strong increase of the near-field intensity in certain “hot-spots” in a polarisation dependent manner. Hence we demonstrate that breaking of symmetry can provide additional centres of “hot-spots”, which will be employed as the basis of an improved structure design to gain highly efficient near-fields focusing.