Lecture: Anderson Localization and Amplification of Light in Low-dimensional Disordered Systems

31.07.2017, 13:30

Randhir Kumar, Tata Institute of Fundamental Research, Mumbai, India


Seminar Room A1.500, MPL, Staudtstr. 2, 91058 Erlangen


Abstract:

In this talk, I will discuss our recent experimental and computational studies on light transport and amplification in one and two dimensional aperiodic media, showing interesting complex phenomena like Anderson localization, random lasing and properties thereof. In 1D media with gain, we present the first experimental observation of signature exponentially decaying wavefunction of longitudinally Anderson localized (AL) modes. Next, we present their temporal pulse-width distribution which shows an intriguing behavior with varying disorder. Our numerical model, based on a synergy of the transfer-matrix method and coupled atom-cavity rate equations, provides excellent agreement with the experiments and reveals the critical role of the random structure of the Anderson modes. In 2D passive media, we study light transport in intentionally disordered quasi-2D GaAs photonic crystal membranes. We measure the universal conductance and inverse-participation-ratios (IPR) of modes that are localized through the Anderson mechanism and the Lifshitz mechanism. Our data suggests the amalgamation of the two mechanisms above a certain degree of disorder. In the end, I will talk about another low-dimensional system which shows amplification of super-critical angle fluorescence using dye molecules and discuss its response to disorder.