【作者】 冷进勇；

【导师】 谭吉春；

【作者基本信息】 国防科学技术大学 ， 光学工程， 2006， 硕士

【摘要】 固体激光器辐射冷却原理是一个新概念,它的提出为降低增益介质中的热沉积量提供了一条新的技术途径。本文研究辐射冷却原理在固体激光器中的应用,通过反斯托克斯荧光的辐射冷却效应来减少掺镱激光介质在泵浦和受激辐射过程中所产生的热量,从而减小热效应对激光介质的不良影响。主要内容概括为:1.综述了现有固体激光器的生热原理,以及反斯托克斯荧光冷却概念及其应用技术的发展历程。系统地叙述了辐射平衡激光器的基本理论,以及激光增益介质选取和工作波长优化的方法;2.采用数值模拟方法,计算了辐射平衡条件下单程放大和振荡器掺镱介质(Yb: KGd(WO4)2)内光强的变化规律;3.运用光线追迹的方法对二极管激光器(LD)侧面泵浦固体激光介质进行数值模拟,得到不同泵浦条件下Yb:KGW介质内泵浦光功率的分布。运用有限元分析软件ANSYS计算不同泵浦条件下介质内的温度分布,分析了影响介质内泵浦光功率分布及温度分布的因素。本文的研究结果对设计辐射平衡激光器泵浦结构、解决传统固体激光器里的主要矛盾——提高激光输出功率与保持较好的光束质量——有一定的指导意义。更多还原

【Abstract】 Optical refrigeration in solid-state lasers, as a new concept, can reduce the heat generated in laser medium in a different approach. Radiation balanced lasers (RBL) are analyzed through numerical simulation in this thesis. In RBL, the heat generation in the gain medium is compensated by optical refrigeration. The main work of the thesis is as follows:1. Heat generation and thermal effects in solid-state lasers were summarized, along with the development of optical refrigeration which uses anti-Stokes fluorescence to realize cooling, and then the basic theories on RBL were represented. Yb:KGW was proposed as the candidate gain medium for RBL and wavelength condition must be satisfied in RBL;2. The pump and laser intensity distributions are plotted in RBL of Yb:KGW under both the single-pass amplifier and resonator cavity conditions;3. Side-pumped solid-state laser with low thermal loading was simulated numerically by ray-trace method, and the pump power distribution is calculated, under different conditions. Using the software ANSYS, we calculate the temperature distribution in medium. At last, the factors which affect the distribution of absorbed power and temperature are analyzed.The conclusions of this paper have some instructional meanings to design the pump source in radiation-balanced lasers and settle the contradictory between increasing the output power and keeping beam quality.更多还原