无序材料中的Polariton在光波导理论中的应用

本文用相干势近似的方法处理了无序材料中的Polariton,得出以下主要结论:(1)对一般介电玻璃,可以引入等效波矢的概念来描述Polariton的行为,并得到了等效波矢存在的判据.(2)无序材料中Polariton的色散关系与晶体中的相似,这与最近的实验结果相符.(3)从无序涨落导致衰减的角度来看,使用Phonon-Polariton频段(红外频段),更有利于实现长距离、无中继的光纤通讯.另外,作为一个应用,本文还导出了无序平面波导中导波耦合场量子的色散关系.

POLARITONS IN A DISORDERED MATERIAL An Application to the Theory of Optical Waveguides

In the present article, the properties of polaritons in a disordered material are studied under the Coherent Potential Approximation. Our main results are ag follows:(1) The concept of an effective wave vector can be used to describe the polariton of a dielectric glass, and the criterion for the existence of effective wave vector is also given. (2) The polariton dispersion of a disordered material is similar to its crystalline counterpart, which is consistent with recent experiments. (3) In the sense of the attenuation due to the disorder of the structure, the phonon-polariton is bettor than the exoiton-polariton in long-distance optical fibre communications. As an application of the present theory, we have derived the dispersion of guided-wave polaritons in a planar disordered waveguide.