Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 49: Ultrafast Phenomena

HL 49.4: Vortrag

Mittwoch, 28. März 2012, 10:15–10:30, EW 202

Localization of light-modes in disordered ZnO nanoneedle-arrays — •David Leipold and Erich Runge — Technische Universität Ilmenau, 98693 Ilmenau, Germany

Whereas Anderson localization of electrons and excitons in solids is well established for about half a century, the localization of light is notoriously hard to observe in experiments due to weak variations of the dielectric properties and/or the presence of absorption.

We present calculations of localized light-modes in dense random arrays of vertically aligned ZnO nanoneedles. This material provides strong scattering accompanied by low absorption and enables experiments to map the localized wavefunction. We present results of full 3D solutions of Maxwell's equations for our model system. We observe light modes whose intensity is concentrated in small spatial areas and, correspondingly, non-Gaussian intensity histograms. Positive correlation between long lifetimes and the degree of localization is observed. The correlation is strongest for the most localized modes.

We thank M. Maschek, S. Schmidt, M. Silies, and C. Lienau from the Carl von Ossietzky Universität Oldenburg as well as T. Yatsui, K. Kitamura and M. Ohtsu from the University of Tokyo, who did the experiments which inspired this theoretical work.