Experimental Observation of a Fundamental Length Scale of Waves in Random Media

Sonja Barkhofen (1) , J. J. Metzger (2, 3) , R. Fleischmann (2) , Ulrich Kuhl (4) , H.-J. Stöckmann (1)

1 Fachbereich Physik [Marburg]
2 MPIDS - Max Planck Institute for Dynamics and Self-Organization
3 Institute for Nonlinear Dynamics, Department of Physics
4 LPMC - Laboratoire de physique de la matière condensée

Waves propagating through a weakly scattering random medium show a pronounced branching of the flow accompanied by the formation of freak waves, i.e., extremely intense waves. Theory predicts that this strong fluctuation regime is accompanied by its own fundamental length scale of transport in random media, parametrically different from the mean free path or the localization length. We show numerically how the scintillation index can be used to assess the scaling behavior of the branching length. We report the experimental observation of this scaling using microwave transport experiments in quasi-two-dimensional resonators with randomly distributed weak scatterers. Remarkably, the scaling range extends much further than expected from random caustics statistics.

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Sonja Barkhofen, J. J. Metzger, R. Fleischmann, Ulrich Kuhl, H.-J. Stöckmann. Experimental Observation of a Fundamental Length Scale of Waves in Random Media. Physical Review Letters, 2013, 111, pp.183902. ⟨10.1103/PhysRevLett.111.183902⟩. ⟨hal-00879515⟩