Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 54: Photonic Crystals: Theory

HL 54.5: Vortrag

Donnerstag, 25. März 2010, 15:00–15:15, H13

Diagrammatic Theory of Anderson Localization of Light in Random Photonic Crystals Including Polarization — Zhong Yuan Lai, •Andreas Lubatsch, and Johann Kroha — Physikalisches Institut, Universität Bonn, Nussallee 12, 53115, Bonn

Anderson localization of light (ALL) is of interest both for fundamental reasons, because it is not disturbed by interaction effects, and for applications, e.g. in random lasers. However, the realization of ALL has been hampered by weak scattering amplitudes as well as by the reduced interference due to the polarization degree of freedom.

We develop a realistic description of diffusion and localization of light in random photonic crystals, where ALL is expected to be enhanced near a photonic band gap. Starting from a Wannier representation, we develop a tight-binding model of the disordered photonic crystal. The transverse vector nature of light implies the existence of two modes per site in the relevant energy band. They are coupled due to the disorder. The resulting pseudospinor theory is analytically tractable with strongly reduced effort compared to a plane-wave expansion [1]. We generalize the existing, selfconsistent theory of Anderson localization of classical waves [2] to include polarization. The transport velocity and the diffusion coefficient are calculated including a selfconsistent resummation of backscattering (``Cooperon'') diagrams.

We find important corrections to the scalar theory due to different disperions of the two polarization modes and due to absorption in the medium.