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 he 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.