【作者】 钟锋；

【导师】 付方正；

【作者基本信息】 南昌大学 ， 理论物理， 2006， 硕士

【摘要】 无序激光器是人们近年发现的有着特殊机理的一类新型激光器。它的形成与安德森(Anderson)局域化密切相关，它是由散射效应提供反馈来实现光放大，且在多个方向上都有输出的激光器，有着广泛的应用前景。本文主要研究了相干反馈无序激光器中循环光的散射形式、模的竞争，以及该无序激光器中的两种光的局域化。 在第三章中，基于前人得出的实验数据和理论，本文详细叙述了光的自发放大现象，并通过对实验数据的分析，说明了放大自发辐射(ASE)到激光辐射的转变过程是一个逐渐变化的过程，Cao．H根据实验结果得出：这种转变发生在当散射平均自由程从14λ降至于5λ的过程当中。 在第四章中，本文探讨相干反馈无序激光器中循环光散射的形式和模竞争。首先根据Cao H．提出的相干反馈无序激光是由循环光散射(即多重散射形成回路)形成的观点，在将纳米ZnO微粒(平均直径约为100nm)加入到激光染料溶液构成的相干反馈无序激光器实验中，对ZnO散射粒子提出了立方体、单面镜的简化模型，并利用Cao H．的实验数据对各种形式回路出现的相对几率进行分析和计算。证明得到二粒子回路比三粒子回路更容易激射，粒子数越多的回路越难激射。实验数据支持该观点。随后本文讨论了任意一个激光模式回路外激光光子的平均寿命，得到光子数目随时间的变化规律，进而研究相干反馈无序激光器中的模竞争，讨论得出在激发出来的激光模式中哪些模式最终形成强的激光。 在第五章中，根据Mujumdar Sushil等人对含ZnO散射粒子的激光染料溶液进行激光泵浦得到的实验观测结果：在光子的平均自由程远大于光波长的时候，仍能观测到尖锐的发射峰，本文提出了在无序激光器中存在两种光局域化的观点：第一种是循环光散射回路使光子局域于回路，回路体积很小，光子寿命较短；第二种是无序介质中的散射粒子使光子局域于整个增益介质，相对回路而言，增益介质体积很大，光子寿命较长。第一种局域化选择特定波长的光子，可“孕育”激光“种子”；第二种局域化延长了激光光子的寿命，放大了激光，并使激光沿各方向发射。通过探讨本文解释这个新的实验现象。更多还原

【Abstract】 The random laser is a new laser that has special theorem which people have discovered in recent years. The formation of the random laser is closely correlated with the Anderson limitation. It is a laser that makes light amplifying by the coherent feedback which is provided by the scattering effect make, and that there is light output in many directions, so it has a widely applying prospect. In this article, we have studied the form of scattering of the recurrent light in random laser with coherent feedback, and the competition of mode, and the two kinds of light’ s limitation in random laser.In the third part, on the base of predecessor’ s experiment data and theory, we expatiate on the phenomenon of the amplifying spontaneously of light, and through analyzing the experiment data, we show that the transition from the amplifying spontaneously radiating to laser radiating is a gradual one. According to the result of the experiment, Cao.H got the conclusion that this transition occurs when the averagely free path of scattering is decreased from 14λ to 5λ. In the forth part, the form of scattering of the recurrent light in random laser with coherent feedback and the competition of mode are studied. Cao H. proposed that the random laser with coherent feedback is generated by recurrent light scattering (closed loop path formed by multiple scattering). Basing on her standpoint, and through the experiment that the random laser is composing by the laser dyeing liquor including ZnO scattering microparticles(the diameter is about 100nm), we propose the simplified models of cube and the only one of six surfaces is mirror for ZnO scattering particle. Utilizing Cao. H’ s experiment data, we analyze and calculate the relative probability更多还原