Wave Propagation and Localization in Random Structures

9311605 Genack这个建议的目的是为了给一个清晰的图片的过渡，从扩散到局部传播的微波和光辐射。 利用可调谐单频源、短脉冲和亚波长空间分辨率，确定了随机散射体系综中波传播的关键统计特性和微观散射参数。 测量了局域波的强度、透射率和电导率的概率分布、相关函数和平均值的标度以及局域波的飞行时间分布。 传播的描述被铸造成一个通用的形式，使用适当的组合的散射参数，样品的几何形状和边界条件。 经典波传播是通信的载体，为发现非均匀系统的结构提供了一种手段。 此外，它还可以作为超小型系统中电子输运的模型。 这个项目的目的是找到一个通用的描述从扩散制度（随机散射从许多中心，如原子和分子）的过渡到“本地化”制度，其中光不再能够通过介质传播。 这是一个微妙而复杂的效应，在半导体世界中的电子中是已知的，但现在正在探索通过宏观介质传播的光学和微波辐射。 该研究对光子材料的开发和紧凑型滤波器和开关等技术应用具有重要意义。 ***

9311605 Genack The aim of this proposal is to give a clear picture of the transition from diffusive to localized propagation for microwave and optical radiation. Using tunable single frequency sources, short pulses and subwavelength spatial resolution, the key statistical characteristic of wave propagation and the microscopic scattering parameters are determined in an ensemble of random scatterers. Measurements are made of the scaling of the probability distributions, correlation function and average value of the intensity, transmission and conductance as well as time of flight distribution of localized waves. The description of propagation is cast into a universal form using appropriate combinations of scattering parameters, sample geometry and boundary conditions. %%% Classical wave propagation is the vehicle for communication and provides a measure for discovering the structure of inhomogenous systems. Moreover, it serves as a model for electronic transport in ultrasmall systems. The aim of this project is to find a universal description of the transition from diffusive regime (random scattering from many centers, like atoms and molecules) to a "localized" regime where the light is no longer able to propagate through the medium. This is a subtle and complicated effect that is known for electrons in the semiconductor world, but is just now being explored for optical and mircrowave radiation propagating through macroscopic media. The research has important implications for photonic materials development and technological applications such as compact filters and switches. ***