【作者】 王薇；

【导师】 朱长虹；

【作者基本信息】 华中科技大学 ， 物理电子学， 2004， 硕士

【摘要】 从1960年激光器发明以来,被动调Q固体激光器由于使用简便、容易实现激光器的小型化等优点而在军事和民用上具有越来越重要的应用价值和广泛的运用前景。文中针对被动调Q激光器输出脉冲重复频率的特性,将数学上的微分方程的稳定性分析与激光动力学过程相结合,根据被动调Q激光器的元件特性,运用协同学中的伺服原理,采用绝热近似得到二阶的被动调Q数理方程,运用Hopf极限环分岔理论推导出被动调Q输出脉冲的重复频率与被动调Q激光器各光学参量之间关系的解析表达式,发现随泵浦功率增加,输出脉冲重复频率近似线性增长;并预测输出脉冲重复频率可能出现增长率饱和而得到稳定的脉冲输出序列。本文提出可饱和吸收体Cr4+:YAG在激光谐振腔中可具有横模选择的作用。采用多元件谐振腔的方法对光腔中横模的空间分布进行研究,得出使用可饱和吸收体 Cr4+:YAG做反射镜的谐振腔能够有效增加基模有效模体积,得到良好的选横模效果的结论。本文对以上研究理论的实验验证表明:输出Q脉冲的重复频率与泵浦功率的关系基本与理论结果相一致;在一定情况下甚至可以看到稳定的重复频率输出;被动调Q激光器的模式优于一般的主动调Q激光器。这一结果对于被动调Q激光器的应用具有重要的意义。更多还原

【Abstract】 Passively Q-Switched lasers have more and more important applications in military affairs and civil affairs. But the investigations on passively Q-Switched lasers are always by numerical and experimental methods. In this paper, the stability of differential eguation has been related with laser dynamics. According as the characteristics of passively Q-switched laser elements, the two dimension differential eguations are got by means of adiabatic elimination approximation (AEA). A formula about the relationship between the important parameter-repetition rate of output pulses and laser’s optical parameter has been obtained by means of Hopf bifurcation theory. The operation of lasers can be forecasted using this formula.The presence of saturable absorber also has influence on laser mode. In this paper, the transverse mode of laser has been researched, and the effect of mode selection has been validated.In this paper, the theoretical results have been validated by experiments. The experiment result of relation between the repetition rate of output pulses and pumping power is accord to theoretical result. In diode-pumped passively Q-Switched lasers, we can even get stable repetition output. And the mode of passively Q-Switched lasers is superior to active Q-Switched lasers. These results will benefit for passively Q-Switched laser’s optimizing design, enhancing stability and increasing output power.更多还原