中红外低浓度无序介质的光子定域化理论研究

提出一些折射率比锗还高的中红外材料(第一类)以及中红外反常色散材料(第二类)可以用于无序介质的光子定域化研究.基于Mie散射理论的研究发现,即使在低浓度散射体近似下,也容易在第一类无序介质中实现光子定域化;同时可在第二类无序介质中实现一定意义下(含一定的吸收)的光子定域化,且频率位于各自的剩余射线带内.研究还发现,基质的折射率效应在这两类无序介质中的作用完全不同.还提出了散射体平均等效散射截面饱和的假设,讨论了因此而导致的问题 关键词： 光子定域化 无序介质 中红外 反常色散

Theoretical study on photon localization in the mid-infrared random media at low density

It is pointed out that some mid\|infrared materials with refractive indices larger than that of Ge (the first kind) and with anomalous dispersion (the second kind) can be applied to the investigations of photon localization. Based on the Mie scattering theory of low concentration approximation in the mid-infrared region, some theoretical results are reported on the studies of the localization parameter in the random media containing these two kinds of dielectric spherical scatterers. Strong photon localization can be expected, when the relative refractive index m is large enough, and predominant backscattering occurrs when m is large than 3.1. Strong photon localization with a computable absorption also appears in the Reststrahlen band of abnormal dispersive dielectric scatterers, and the roles of the matrices in these two kinds of random media are very different from each other. The new concept of effective scattering cross section saturation is put forward, and the possibility of perfect localization in mid-IR region is discussed.