Dresden 2006 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 42: Critical Phenomena and Phase Transitions II

DY 42.5: Vortrag

Donnerstag, 30. März 2006, 12:00–12:15, H\"UL 186

Observation of the critical regime near Anderson localization of light — •Martin Störzer, Peter Gross, Christof Aegerter, and Georg Maret — Fachbereich Physik Universität Konstanz; Universitätstrasse 10; 78457 Konstanz

Diffusive transport is among the most common phenomena in nature. However, as predicted by Anderson, diffusion may break down due to interference. The transition from diffusive transport to localization of waves should occur for any type of classical or quantum wave in any media as long as the wavelength becomes comparable to the transport mean free path ℓ^*. The signatures of localization and those of absorption, or bound states, can however be similar, such that an unequivocal proof of the existence of wave localization in disordered bulk materials is still lacking. Here we present time resolved measurements of light transport through strongly scattering samples with kℓ^* values as low as 2.5. In transmission, we observe deviations from diffusion which cannot be explained by absorption, sample geometry or reduction in transport velocity. Furthermore, the deviations from classical diffusion increase strongly with decreasing ℓ^* as expected for a phase transition. This constitutes an experimental realization of the critical regime in the approach to Anderson localization.