随机介质介电常量的涨落与光波的空间分布  

The Effects of Dielectric Constant Fluctuation on the Spatial Distribution of Light Waves in Random Materials

作　　者：王宏[1] 刘劲松[1] 

机构地区：[1]华中科技大学激光技术国家重点实验室,武汉430074

出　　处：《光学学报》2004年第6期793-797,共5页Acta Optica Sinica

基　　金：国家自然科学基金 (6 0 3780 0 1);湖北省自然科学重点基金 (2 0 0 1ABA0 0 3)资助课题

摘　　要：采用随机介质统计模型和时域有限差分方法模拟了二维随机介质中光场的空间分布及其同介电常量涨落的关系。模拟中 ,散射微粒随机地分布在均匀介质中以增加光子在介质中滞留时间。不同随机强度α ,形成不同空间结构的随机介质。通过小心地调节入射光波长 ,得到了不同随机介质中的场强分布。结果表明 ,随机介质介电常量的涨落导致在介质的某些区域形成一些特殊结构。这些结构延长了光子在其中的滞留时间 ,产生了光波的局域态 ,起到了光腔的作用 ,使得随机介质在抽运激励下能够产生激光辐射。这样的光腔在介质中是随机分布的 ,其数量与分布特征与介电常量涨落的强弱有关。The effects of the dielectric constant fluctuation on the spatial distribution of light waves in two-dimensional random media are investigated by use of the statistical model of random media and the finite difference time domain (FDTD) method. Dielectric scatters are randomly embedded in a homogeneous medium to increase the dwell time of light in the random medium. For different strength of randomness, α, the different random media can be formed. The field pattern of different samples have been obtained numerically by carefully locating the wavelength. Results show that the fluctuation on dielectric constant results in some special configurations in a random medium. Such configurations trap the lightwave and delay relaxation time of the photon in it, and make optical localized states creating in the medium, which play a role similar to an optical resonator, results in laser oscillation in a random medium for a pump beam. Such optical resonators distribute randomly in the random medium and their amount and distributing characteristics depend on the strength of the dielectric constant fluctuation.

关 键 词：激光物理 随机激光器 时域有限差分法 随机介质 统计模型 光学微腔 随机强度 

分 类 号：TN241[电子电信—物理电子学]