2μm波段掺Tm，Ho氟化物激光晶体的研究
文献类型：学位论文
| 作者 | 彭海燕 |
| 学位类别 | 硕士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 张连翰 |
| 关键词 | 激光晶体 晶体生长 2μm激光 Tm离子 Tm,Ho共掺 |
| 其他题名 | Studies on the Tm, Ho, doped-fluoride laser crystals in 2μm range |
| 中文摘要 | 由于在大气传输和对人眼安全的特性， 2μm激光被认为是应用于医疗和人眼安全探测系统的理想光源，包括医用手术、激光测距，激光差分仪、相干多普勒测风雷达等。这些促使研究人员更多的探索研究品质高、光学性能及热学性能好的晶体材料，以获得更高效率和功率的激光输出。 Tm3+具有与商用二极管匹配良好的吸收峰以及交叉弛豫量子效率接近于2的特性，掺Tm3+固体激光器是近年来2m激光器研究的重点方向之一。而Tm,Ho离子掺杂晶体以获得2μm激光的研究也越来越受到研究人员的青睐，Tm,Ho离子发光分别是基于3H4→3H5 和5I7→ 5I8 能级间的跃迁。研究表明，Ho3+ 5I7→ 5I8 能级间跃迁的增益（吸收截面×寿命）比Tm3+ 3H4→3H5 能级间跃迁的增益大的多，但是Ho3+不具有与激光二极管泵浦原相匹配的吸收带，而Tm的吸收带则刚好和激光二极管相匹配，这导致研究人员将研究方向转向Tm,Ho离子共掺。室温下Tm,Ho离子共掺晶体获得2μm激光输出是基于Ho3+ 5I7→ 5I8 能级间跃迁，Tm敏化离子能够有效的给Ho亚稳态提供泵浦能量。 本文以Tm:LiYF4、Tm: LiLuF4及Tm,Ho: LiLuF4作为研究对象.简要介绍了2μm 波段激光晶体的历史背景、国内外发展现状及以后的发展趋势，并开展了以下两个方面的研究工作: 1、Tm:LiYF4、Tm: LiLuF4晶体的生长、光谱及激光性能研究。 采用提拉法成功生长了Tm（2at%）:LiYF4、Tm（2at%）: LiLuF4晶体。晶体透明、完整不开裂、内部无包裹物、散射少。通过XRD对Tm:LiYF4、Tm: LiLuF4晶体进行了结构分析。 测试并分析了Tm:LiYF4、Tm: LiLuF4晶体的吸收光谱和荧光光谱，Tm: LiLuF4晶体的吸收系数比Tm:LiYF4晶体高。通过吸收光谱研究了Tm离子的能级结构、计算了Tm离子对不同波长的吸收系数和吸收截面。 根据吸收光谱，通过J-O理论计算了Tm离子在LiYF4、LiLuF4晶体光谱线强度参数、两个能级间的跃迁几率、跃迁截面辐射寿命、荧光强度、荧光分支比、量子效率等参数。 对Tm（2at%）:LiYF4、Tm（2at%）: LiLuF4晶体进行了激光实验，并比较了两者的激光性能。 2、Tm,Ho: LiLuF4生长、光谱和激光性能研究 采用提拉法成功生长了Tm（5%）,Ho（0.5%）:LiLuF4晶体。通过XRD和ICP等测试手段，对Tm（5%）,Ho（0.5%）:LiLuF4晶体的物相结构和分凝特性进行了分析。测试并分析了Tm（5%）,Ho（0.5%）:LiLuF4晶体的吸收光谱和荧光光谱，研究了Tm,Ho共掺的发光机制。测试了Tm（5%）,Ho（0.5%）:LiLuF4晶体的激光性能。 |
| 英文摘要 | During the last few years, interest in 2μm laser has increased for its eye-safe characteristics when it propagates through the atmosphere. 2μm laser is considered to be an ideal source for medical applications and eye-safe detection, including laser ranging, laser differential instrument and coherent Doppler velocimetry, etc. Due to 2μm laser’s large variety of applications in those areas, crystals with high quality, excellent optical and thermal properties are investigated for a higher efficiency and power of 2μlaser output. Tm doped solid laser is one of the main aspect in 2μm laser research. For the reason that the absorption band of Tm3+ ions can well match with commercial applied diode lasers and its quantum efficiency can reach 2 as the result of cross relaxation. On the other hand, Crystalline materials doped with Tm and Ho for obtaining 2 micron laser, which is based on Tm 3H4→3H5 and Ho 5I7→ 5I8 transitions, have attracted more and more attention from researchers. Previous researches indicated that Ho3+ 5I7→ 5I8 transition showed much more gain (gain=absorption cross section× life time) than that of Tm3+ 3H4→3H5 transition. But Ho3+ doesn’t have an absorption band to match the emission of available laser diodes, hence there is a need to co-dope with Tm irons which have the absorption band matching the laser diodes emission. At room temperature 2μm laser emission of Tm and Ho co-doped crystals is based on Ho3+ 5I7→ 5I8 transition, Tm ions play as sensitizing irons transporting pump energy to the metastable state of Ho ions. This paper uses Tm:LiYF4, Tm: LiLuF4 and Tm,Ho: LiLuF4 crystals as objectives of research. We first briefly introduced research background, development status at home and abroad and research trends of 2μm laser crystals. The research work is summarized as the two following aspects: 1. Research on the growth, optical properties and laser characters of Tm:LiYF4 and Tm: LiLuF4 crystals. Tm（2at%）:LiYF4 and Tm（2at%）: LiLuF4 single crystals were successfully grown by the Czochralski Technique. The as-grown crystals were well transparent, intact shape and free from instinct deficiency. Structure of Tm:LiYF4 and Tm: LiLuF4 crystals were analysed through the measure of XRD. The absorption and fluorescence spectrums of the crystals were also carried out and researched, which indicated that the absorption index of Tm: LiLuF4 crystal was higher than that of Tm:LiYF4 crystal. By analysing the absorption spectrums of the crystals, the energy structures of Tm3+ ions were obtained, absorption index and absorption cross section at different wavelength were calculated. The Judd-Ofelt theory was applied to obtain the intensity parameters Ωt(t=2,4,6), which were used to calculate the radiative transition rates, branching ratios, radiative life-times, quantum efficiency and fluorescence branch ratio of Tm3+ ions. A comparative study of the laser properties of Tm（2at%）:LiYF4 and Tm（2at%）: LiLuF4 crystals was presented by carrying out laser experiments on these crystals. 2. Research on the growth, optical properties and laser characters of Tm,Ho:LiLuF4 crystals. The Czochralski Technique was used to grow Tm（5%）,Ho（0.5%）:LiLuF4 crystal. Measurements of XRD and ICP were carried out on the crystal to study its phase structure and segregation properties. The absorption and fluorescence spectrums of the crystal were also carried out and analysed to obtain the Luminescence Mechanism in Tm, Ho co-doped crystals. The laser performance of the Tm（5%）,Ho（0.5%）:LiLuF4 crystal was also studied. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16631]  |
| 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 | 彭海燕. 2μm波段掺Tm，Ho氟化物激光晶体的研究[D]. 中国科学院上海光学精密机械研究所. 2009. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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