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DF: Fachverband Dielektrische Festkörper

DF 9: Poster Session

DF 9.4: Poster

Dienstag, 21. März 2017, 14:00–16:00, P1C

A field-theoretical approach to light propagation and lasing in disordered photonic media — •Zhong Yuan Lai, Oleg Zaitsev, and Johann Kroha — Physikalisches Institut, Universität Bonn, Germany

Random lasing is a phenomena which has continuously received attention since its experimental discovery in 2000. We study the propagation of light in an optically active, nonlinear and dielectrically disordered medium using a functional integral formalism, which enables the derivation of an effective low-energy action, known as the Keldysh nonlinear sigma model [1]. In addition, we were able to calculate explicit transport quantities in the form of counting statistics [2] which we could show, in the case of nonactive media, to be quantitatively the same as previous diagrammatical calculations. Finally we study random lasing by including the full matter-light interacting picture and integrating out the matter fields, thus exposing the nonlinear nature of effective photonic interactions in our theory. By obtaining the full interacting saddlepoint of the nonlinear sigma model and systematically taking into account fluctuations around the saddlepoint we obtain the diffusive modes. In this manner we are able to obtain the photonic density correlation function with a correlation length which we intepret as the average lasing spot size, and the single-particle Green’s function which yields information about the average laser linewidth.
[1] Lai, Z. Y. and Zaitsev, O., Phys. Rev. A 85, 043838 (2012).
[2] Lai, Z. Y. and Zaitsev, O., Phys. Rev. A 88, 023861 (2013)