Microscopic Theory of Light Propagation and Localization in Periodic, Disordered, and Laser-active Media

在光波长的长度尺度上周期性或随机地构造介质（烧结的电介质粉末等），以及介电响应中的非线性可以极大地改变介质中的光的特性。该项目的目标是发展理论，在微观层面上提供对这种介质中光发射，传播和定位的基本特性的理解，从而有助于在微光学器件的设计中使用这些特性。该项目包括两个不同的研究主题：（1）由于粒子-等离子体激元和光子波导模式（粒子-等离子体激元极化激元）的耦合，金属纳米颗粒的二维波导中的非线性光学效应。(2)在没有宏观谐振腔的强无序有源介质中的激光作用，其中光限制和激光反馈通过多重随机散射（“随机激光”）实现。这两个主题是相互关联的，无论是在物理系统的研究和用于他们的调查方法。半解析描述自洽费曼传播技术将补充数值时域有限差分（FDTD）计算的波场。子项目（1）将特别与项目C1密切合作完成。

Structuring a medium an the length scale of the light wavelength, either periodically or randomly (sintered dielectric powders etc.), as well as non-linearities in the dielectric response can drastically alter the properties of light in the medium. The goal of this project is to develop theories which provide, on a microscopic level, an understanding of the fundamental properties of light emission, propagation, and localization in such media, and which may thereby help to employ these properties in the design of micro-optical devices. The project encompasses two distinct research topics: (1) Non-linear optical effects in twodimensional wave guides with metallic nanoparticles due to coupling of particle-plasmons and photonic wave-guide modes (particle-plasmon polaritons). (2) Laser action in strongly disordered, active media without macroscopic resonator, where light confinement and laser feedback are achieved by multiple random scattering ("random laser"). The two topics are related to each other both with respect to the physical systems studied and to the methods used for their investigation. The semi-analytic description by self-consistent Feynman propagator techniques will be complemented by numerical finite difference time domain (FDTD) calculations of the wave fields. Subproject (1) will be done especially in close collaboration with Project C1.