Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 27: Photonic crystals III

HL 27.8: Talk

Tuesday, February 26, 2008, 18:00–18:15, EW 203

Polaritonic band gaps in gold films covered with high-refractive index gratings — •Alexander Sprafke, Karl Weis, and Gero von Plessen — I. 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 plasmon-polariton dispersions. Here, we investigate the polaritonic band gaps of gold films coated with high-refractive index (n > 2) gratings. The dependence of the band-gap width on the refractive index and filling factor of the gratings is studied experimentally and theoretically. In particular, the ultimate limits on the band-gap width achievable in these structures are discussed.