1.6微米全固态激光技术
文献类型：学位论文
| 作者 | 朱亮 |
| 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 | 陈卫标 |
| 关键词 | 1.6微米，掺Er激光器，人眼安全，全固态激光技术，上转换 |
| 其他题名 | 1.6 um All-Solid-State Laser Technology |
| 中文摘要 | 1.6 微米激光处于人眼安全波段和大气窗口，在科研、医疗、工业等领域得到关注，具有重要的应用前景，并已经在多普勒测风雷达系统、光谱学、成像等众多领域得到快速应用。1.6 微米激光可以通过OPO非线性方法或拉曼频移间接获得，但该类方法效率低，结构复杂，最简便方法是利用半导体激光器直接泵浦掺Er增益介质来获得1.6 微米全固态激光器。但由于掺Er激光介质通常受到严重的上转换效应及较大热效应的限制，使得1.6 微米全固态激光技术的进展不快。因此，深入研究掺Er介质全固态激光器的性能，成为获得高效率1.6 微米激光器的关键。 本文对典型的Er单掺介质和Er、Yb双掺介质两类常用的掺Er激光介质的连续和调Q性能做了详细研究。最终选取了适合于获得高功率、高效率的介质：Er:YAG晶体，研究了其上转换行为，并进一步探求抑制上转换和提高效率的有效方案。论文第一章首先对掺铒激光介质进行了分类描述，并介绍了上转换机制和不同类别增益介质的激光机制，然后对LD泵浦和Er光纤激光器泵浦的Er:YAG激光器做了比较，并对LD泵浦的Er:YAG激光器的发展状况和困难做了介绍。第二章首先详细描述了Er:Yb:YVO4晶体的连续和调Q激光实验结果，在连续出光下获得230 mW最大输出，斜率效率4.5%，阈值为1.69 W，500Hz调Q重频时获得0.19 mJ最大脉冲能量，对应的脉冲宽度为130ns；该章节最后对其调Q状态下激光上能级寿命的降低做了解释。第三章首先通过进一步降低Er掺杂浓度，成功抑制了LD泵浦的Er:YAG激光器中的上转换和热效应问题，并获得了接近量子效率的吸收斜率效率；接下来对调Q性能做了详细描述，在100 Hz调Q重复频率下获得了7 mJ最大脉冲能量，对应脉冲宽度为65 ns；最后指出了目前泵浦吸收不足的问题，并提出两种解决方案。第四章详细推导了单端泵长晶体的热透镜等效模型。该模型可以简便、近似的计算单端泵长晶体情况下晶体端面激光模式大小，极大地简化了腔型设计。该模型参照第三章中两种改进方案的实际情推导获得，但数值模拟证明其结论对于所有单端泵长晶体情况都近似适用。论文最后对本论文所做工作进行了简单总结，并就1.6微米全固态掺Er激光器未来发展方向提出了自己的观点。 |
| 英文摘要 | Due to the eye-safe band and the atmospheric window, solid-state lasers around 1.6 um has been paid attention, and rapidly been applied in such as Doppler wind lidar, imaging, and spectroscopy. The normal ways of obtaining 1.6 um lasers are such as OPO or Raman translation, while these methods suffer from low efficiency and complicate setup. All solid-state diode pumped Er doped medium has great potential to obtain 1.6 um laser with high efficiency and simple configuration. However, the laser performance of such medium is strongly limited by Er up-conversion and thermal problem. In order to achieve efficient Er doped lasers, the further insight of the fundamental physics and characters in Er doped medium is essential. In this thesis, two typical Er doped mediums, namely, Er single doped medium and Er, Yb co-doped medium were investigated in both continuous-wave and Q-switched operation. Er:YAG crystal was chosen for its good performance in efficiency. The up-conversion effect in Er:YAG laser was then studied. In the first chapter, Er doped mediums were classified and described. Laser mechanism and the mechanism of up-conversion were then explained. LD pumped Er:YAG laser was summarized and compared with Er fiber laser pumped Er:YAG laser, and the difficulty of LD pumped Er:YAG laser was also presented. In the second chapter, the continuous-wave and Q-switched performance of Er:Yb:YVO4 crystal was studied. 230 mW maximum output with 4.5% slope efficiency and 1.69 threshold was obtained in continuous-wave operation. 0.19 mJ, 130 ns Q-switched pulses were achieved with 500 Hz pulse repetition rate in Q-switched operation. The decreased storage time of upper laser level was analyzed. In the third chapter, the up-conversion effect and the induced thermal effect in LD pumped Er:YAG were effectively suppressed by reducing Er doping concentration. The slope efficiency close to quantum efficiency was achieved. The Q-switched performance of LD pumped 1.6 um Er:YAG laser was also fully investigated, in which 7 mJ, 65 ns pulses were achieved with 100 Hz pulse repetition frequency. Two setups were suggested for future improving efficiency of the laser. In the fourth chapter, an equivalent optical model for thermal lens in single-end-pumped long medium was introduced, which will simplify the laser cavity design greatly. The idea of this model derived from the two suggested plans in chapter three, but the model is a good approximation for nearly all cases with single-end-pumped long mediums. In the last chapter, the main works were summarized, and personal opinions about the future of 1.6 um Er doped lasers were presented. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16721]  |
| 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 | 朱亮. 1.6微米全固态激光技术[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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