Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 52: Time-Resolved Spectroscopy III

O 52.12: Vortrag

Mittwoch, 27. Februar 2008, 18:00–18:15, MA 042

Surface States and Kramers-Kronig relations in one-dimensional Photonic Crystals — •Michael Bergmair and Kurt Hingerl — CD-Labor für oberflächenoptische Methoden, Institut für Halbleiter- und Festkörperphysik, Universität Linz, Austria

Surface states provide very interesting features such as large field enhancement and are very sensitive to the geometry and dielectric behaviour of the investigated structure. A thin metallic sheet allows to investigate the near field and permits a design of a system with negative refracting behaviour. A one-dimensional photonic crystal consisting of layers which have a resonant dielectric behaviour in the infrared (photon-phonon coupling) show very interesting surface states: due to the coupling of bulk and surface states around the resonant frequency a dispersion with negative group velocity occurs. In this region the damping remains small yielding a large figure of merit n′/n″ which is the ratio of real and imaginary part of the dielectric function. In our work we will calculate the dispersion of such coupled surface states and unveil the mechanism that leads to this small damping values. Furthermore we investigate whether and how Kramers-Kronig relations can be applied to systems where the internal structure is on the order of the wavelength.