Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 43: Photonic crystals I

HL 43.8: Talk

Thursday, March 26, 2009, 11:45–12:00, POT 151

Polaritonic band gaps in gold films covered with high-refractive index gratings — •Alexander Sprafke, Karl Weis, and Gero von Plessen — Institute of Physics (1A), RWTH Aachen University, 52056 Aachen, Germany

In structured noble-metal films, surface-plasmon polaritons (SPPs) can be excited optically. SPPs consist of electromagnetic surface waves accompanied by longitudinal electron-density waves. Polaritonic crystals made from planar metal films covered with dielectric gratings have been shown to exhibit band gaps in the polariton dispersions. Here, we experimentally and theoretically investigate the polaritonic band gaps of gold films coated with high-refractive index (n > 2) gratings. The band-gap widths achievable in these structures are studied. In particular, the dependence of the band-gap width on the refractive index and filling factor of the gratings are discussed. We find that the polaritonic band-gap collapses for certain combinations of these parameters. Furthermore, strong variations of the polariton line width as a function of the refractive index and filling factor are predicted.