14 research outputs found
Localization of Classical Waves in Weakly Scattering Two-Dimensional Media with Anisotropic Disorder
We study the localization of classical waves in weakly scattering 2D systems
with anisotropic disorder. The analysis is based on a perturbative
path-integral technique combined with a spectral filtering that accounts for
the first-order Bragg scattering only. It is shown that in the long-wavelength
limit the radiation is always localized, and the localization length is
independent of the direction of propagation, the latter in contrast to the
predictions based on an anisotropic tight-binding model. For shorter
wavelengths that are comparable to the correlation scales of the disorder, the
transport properties of disordered media are essentially different in the
directions along and across the correlation ellipse. There exists a
frequency-dependent critical value of the anisotropy parameter, below which
waves are localized at all angles of propagation. Above this critical value,
the radiation is localized only within some angular sectors centered at the
short axis of the correlation ellipse and is extended in other directions.Comment: 10 pages, 5 figure
Mobility Edge in Aperiodic Kronig-Penney Potentials with Correlated Disorder: Perturbative Approach
It is shown that a non-periodic Kronig-Penney model exhibits mobility edges
if the positions of the scatterers are correlated at long distances. An
analytical expression for the energy-dependent localization length is derived
for weak disorder in terms of the real-space correlators defining the
structural disorder in these systems. We also present an algorithm to construct
a non-periodic but correlated sequence exhibiting desired mobility edges. This
result could be used to construct window filters in electronic, acoustic, or
photonic non-periodic structures.Comment: RevTex, 4 pages including 2 Postscript figure
Ueber eine besondere Art monocularer Relief-Anschauung
UEBER EINE BESONDERE ART MONOCULARER RELIEF-ANSCHAUUNG
Ueber eine besondere Art monocularer Relief-Anschauung (9) (-