[Zurück]

A. Girschik, S. Rotter, F. Libisch, J. Doppler:
"New Insights on Coherent Wave Transmission through Disordered Systems";
Vortrag: 9th International Workshop on Disordered Systems, San Antonio, Texas, USA (eingeladen); 18.08.2014 - 22.08.2014.

I will report on recent projects focused on the coherent scattering of waves in disordered media or at corrugated surfaces. In the first part of my talk I will speak about our theoretical and experimental studies on microwave scattering through systems which are so
strongly disordered, that the effect of Anderson localization suppresses all but a single transmission channel [1]. As a result, we can describe the entire disordered sample in this deeply localized limit as an effective 1D system with a renormalized localization length. We show that the dominant transmission channel is formed by an individual Anderson-localized mode or by a so-called "necklace state". Using pulsed excitations of the disordered samples allows us to identify long-lived localized modes and short-lived necklace states at long and short time delays, respectively.

In a second project, we study the wave transmission through wave guides with surface corrugations [2,3]. We show that for a quantitatively accurate description of such a situation, scattering processes need to be taken into account which are of higher order in the surface corrugation amplitude than those which are conventionally considered. Including these higher-order terms, we are able to provide fully analytical expressions for the multimode
wave guide transmission which are in excellent agreement with independently obtained numerical results [2]. Based on this comprehensive approach we find and explain pronounced reflection resonances in wave guides with a step-like surface profile - a robust effect which has been overlooked in previous studies of the same system. I will also explain how these insights allow us to design wave guides with transmission band gaps in predetermined frequency intervals - an approach which was recently implemented also experimentally [3].

[1] Pena A, Girschik A, Libisch F, Rotter S, and Chabanov A A, Nature Commun. 5, 3488 (2014)
[2] Doppler J, Mendez-Bermudez J A, Feist J, Dietz O, Krimer D O, Makarov N M, Izrailev F M, and Rotter S, New J. of Phys. 16, 053026 (2014)
[3] Dietz O, Stockmann H-J, Kuhl U, Izrailev F M, Makarov N M, Doppler J, Libisch F, and Rotter S, Phys. Rev. B Rapid Comm. 86 201106 (2012)

waveguides, optics, single-channel, transmission, transport, quantum