Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 17: Plasmonic Systems

HL 17.5: Vortrag

Montag, 26. März 2012, 16:00–16:15, EW 203

Bandgap Tuning in Plasmonic Gratings — •Jens Ehlermann, Hoan Vu, Markus Bröll, Robert Blick, Detlef Heitmann, and Stefan Mendach — Institute of Applied Physics, University of Hamburg, Germany

We investigate plasmon excitations on thin goldfilms coated with PMMA grating structures both, in the near field, using a scanning nearfield optical microscope (SNOM), and in the far field. Particular interest is being paid to the characteristics of the bandgap at k=0 in the plasmon dispersion relation.

The dependence of the bandgap’s size and energetic position on structural parameters like grating height and filling factor f, i.e. the ratio between grating bar width and period, is examined. We discovered a shift of the bandgap’s position to lower energies with increasing f and we noticed a significant change in the bandgap’s size.

Our results enabled us to trace back the measured far field effects to the filling factor dependent variation of the effective refractive index.

Experimental data can be well modeled using FDTD and RCWA simulations. Based on these findings it is possible to manufacture structures with tailor-made plasmonic properties whose application covers a broad range of topics.

We gratefully acknowledge support by the University of Hamburg and the DFG through GrK 1286 and the LExI Cluster ’Nano Spintronics’.