晶体热效应补偿的高功率Yb:SSO全固态激光器研究
文献类型：学位论文
| 作者 | 张瀚尹 |
| 学位类别 | 硕士 |
| 答辩日期 | 2012 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 梁晓燕 |
| 关键词 | 热效应 全固态激光器 Yb:SSO晶体 Nd:YVO<sub>4</sub>晶体 |
| 其他题名 | The research of high power Yb:SSO solid-state lasers with the thermal effect compensation |
| 中文摘要 | 20世纪90年代，随着InGaAs 半导体激光器（LD: Laser Diode）制备工艺的逐步完善以及生产成本的大幅度降低，全固态激光器的研究工作取得了重大的进展。激光二极管泵浦的全固态激光器由于其效率高、体积小、重量轻、功率高、光束质量好，可靠性高、寿命长、运转灵便（连续/重复频率/长/短脉冲）等一系列优点，已成为激光发展领域中最具前景的方向之一。近年来，全固态激光器技术日趋成熟，已经被广泛应用于科研、材料加工、军事国防、医疗和显示等领域。 目前全固态激光器已经可以达到很高的能量输出。输出功率的进一步提升受到了热效应的限制，因而，热效应的定量分析以及如何补偿已经成为研究此类激光器的一个重要内容之一，对于获得高功率、高光束质量输出至关重要。 本文主要针对端面泵浦的全固态激光器中增益介质热效应的补偿进行了研究。通过设计和优化腔型，对Yb:SSO全固态激光器中的热透镜效应进行补偿，得到了高转换效率、高功率、高光束质量的输出。同时，定量测量了Nd:YVO4锁模激光器晶体的热透镜焦距，为今后的高功率锁模激光器中热透镜的补偿提供了依据。最后对掺Yb的氟磷酸盐玻璃的激光性能做了研究。主要研究成果如下： 1. 通过对热效应不敏感的谐振腔的研究，用腔型等效替换的方法设计了补偿晶体热透镜的谐振腔。将这一腔型设计用于Yb3+掺杂浓度为5%的Yb:SSO晶体激光器，在T=3%，晶体吸收的泵浦功率为11.7W的情况下，获得了最大输出功率8.8W，对应的斜率效率高达85.5%，输出波长为1062.6 nm的连续输出。输出激光的光束质量和稳定性良好，这是目前基于Yb:SSO获得的最高效率的输出。证明我们设计的热透镜补偿谐振腔是有效的。同时，我们对输出波长进行了调谐，得到的调谐范围是1002.30- 1068.47 nm，对应的调谐宽度为66.17 nm。 2. 用多点测量拟合法，对半导体激光泵浦的Nd:YVO4晶体连续锁模激光器的热透镜焦距进行了测量和拟合。通过对LD泵浦的脉宽为9 ps，输出波长为1064 nm，最高输出功率为1.67 W的Nd:YVO4晶体连续锁模脉冲的光斑半径进行多点测量，得到实际高斯光束的束腰位置、束腰半径以及M2质量因子的数值。获得了晶体热透镜焦距的具体数值，并且得到泵浦功率为6.2W时，SESAM上的激光峰值功率密度为6.6*105W/mm2。为了保证SESAM正常的锁模运转，应当使SESAM上的光功率密度小于该值。 3. 对掺Yb3+氟磷酸盐玻璃的激光性质进行了探索性实验研究。利用Yb3+掺杂浓度为2mol%的氟磷酸盐玻璃，在样品吸收的泵浦功率为4.85W时，我们获得了波长为1060 nm，斜率效率为30.78%，功率为1.15W的连续输出。通过实验发现，此激光玻璃若想获得更高功率的输出，还需在玻璃的热导性、均匀性以及激活离子掺杂浓度等方面进行优化。 |
| 英文摘要 | In the 1990s, with the gradual improvement of the preparation process in InGaAs laser diodes（LD）, as well as a significant reduction in production costs, there was a significant progress in the solid-state lasers. The solid-state lasers pumped by LD due to its high efficiency, small size, light weight, high power, good beam quality, high reliability, long service life a number of advantages, has become one of the most promising direction in the field of laser. In recent years, solid-state lasers has been widely used in scientific research, materials processing, military defense, medical and display. At present, all-solid-state lasers have reached a high output energy. Further improvement of output power was restricted by the thermal effect. Thus, the causes of the thermal effects and how to compensate or even eliminatethe thermal effect has become an important element. In this paper, we studied on the compensation for the thermal effects of the gain medium in the end-pumped solid-state lasers. Through a suitably designed cavity, the thermal lens effect of Yb:SSO was compensated, and we got high efficiency, high power output laser. Then we measured the thermal focal length of the Nd:YVO4 mode-locked laser, which providing a basis for the compensation of thermal focal length in the mode-locked laser. Finally, we studied on laser performance of Yb:fluorophosphate glass. The main result in the dissertation have been summarized as followed: 1. We designed a resonator that was insensitive to the thermal focal length fluctuations and alignment perturbations of cavity. We used this resonator to got a maximum output power of 8.8W at 1062.6nm with absorbed pump power of 11.7W, corresponding to a slope efficiency of 85.5% and an optical-to-optical conversion efficiency of 48.9% in a single diode-pumped CW Yb:SSO laser. Because the thermal lens effect was well compensated, the Yb:SSO laser exhibited excellent output performance. The wavelength tuning of the Yb:SSO laser pumped by 976nm LD was also examined. The tuning range is from 1002.30 to 1068.47nm, corresponding to a tunability range of 66.17nm. 2. Using CCD camera to determine the thermal focal length of the Nd:YVO4 in end-pumped mode-locked laser. 3. We studied on laser performance of Yb:fluorophosphate glass. The highest output power was achieved with an absorbed pump power of 4.85W. We got the maximum output power of 1.15W at 1060 nm, corresponding to slope efficiency of 30.78%. In order to achieve high output power, the thermal conductivity, uniformity as well as doping concentration of Yb3+ should be optimized. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16736]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 张瀚尹. 晶体热效应补偿的高功率Yb:SSO全固态激光器研究[D]. 中国科学院上海光学精密机械研究所. 2012. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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