Dresden 2017 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 14: Various Topics II

DF 14.8: Vortrag

Mittwoch, 22. März 2017, 17:40–18:00, GER 37

Self-consistent theory of Anderson localization for vector waves in disordered photonic media — •Zhong Yuan Lai, Michael Golor, and Johann Kroha — Physikalisches Institut, Universität Bonn, Germany

Anderson localization of light in a random dielectric system is still a controversial issue due to the vector nature of light. We investigate the effects of the vector nature of light on propagation properties in photonic crystals with binary disorder. Due to the transverse nature of light (∇ · D^→=0), the three vector components reduce to the well-known, two-fold polarization degrees of freedom, that is, in two orthogonal polarization modes on each lattice site in a three-dimensional lattice. It can be described as a pseudospin-1/2 degree of freedom. Hopping in the random lattice induces flipping of the pseudospin (mixing of the polarization modes) in analogy to random spin-orbit scattering in electronic systems. We generalize the photonic Coherent Potential Approximation (CPA) to this pseudospin system in order to calculate single-photon properties like the self-energy and density of states (DOS). To calculate transport properties, we generalize the Vollhardt-Wölfle theory of Anderson localization to the case of vector waves, using the pseudospin representation. We find localizing and antilocalizing contributions to the diffusion coefficient D(Ω) in the pseudospin singlet and triplet channels, analogous to random spin orbit scattering. We calculate the corresponding phase diagram of Anderson localization. Our results may provide a systematic way of analyzing the difficulties in achieving light localization in experiments.