新型流体激光介质的探索研究
文献类型：学位论文
| 作者 | 叶云霞 |
| 学位类别 | 博士 |
| 答辩日期 | 2007 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 范滇元 |
| 关键词 | 流体激光器 随机激光 纳米材料及表面修饰 JO理论 蒙特卡罗方法 |
| 其他题名 | Research on new fluid laser medium |
| 中文摘要 | 激光工作介质的物态有固体、液体、气体、半导体和等离子体等，在激光技术40多年的发展历史中，多种物态的激光器，特别是全固态激光器，得到了长足的发展和广泛的应用。而液体介质，除染料溶液外，由于其本身的缺陷和技术条件限制，没有发展成为有实用价值的激光器。近年来，在激光武器、激光聚变和激光加工等应用需求的牵引下，大能量、高功率激光有了迅猛发展，其中，液体介质激光以其热管理、比重量和定标放大能力等方面的独特性能和发展潜力，重新受到关注。 本文综合评估了国内外液体激光器的发展趋势，深入分析已有技术路线的优缺点，在此基础上，确定了探索研究“有机液体溶解型”和“固体纳米分散型”两类液体激光介质新体系。从介质制备的技术要求和技术路线、光损耗和光谱特性的表征以及随机散射工作机制等方面，对新体系的技术可行性作了系统的理论和实验研究，取得重要进展，为发展新型液体激光器奠定了基础。 本文的主要研究内容如下： 1、制备了Nd(TTA)3溶解于几种极性溶剂的溶液试样，详细研究了这些掺Nd3+的溶解型有机介质的光损耗与光谱性能。通过实验测量、Judd-Ofelt理论计算以及阈值估算，分析评价了其作为激光材料的可行性。 2、首次提出并研究了微纳尺度固体材料均匀分散于液体载体中的“纳米分散型”新体系。通过蒙特卡罗方法仿真光子在随机散射介质中的传输损耗，确定了对固体微粒的尺度要求；应用表面修饰等关键技术解决了微粒团聚和沉淀的难题，成功地获得纳米Nd2O3均匀分散于极性溶液的透明流体介质。详细研究了掺Nd3+纳米分散体系的光损耗和光谱性能。通过实验测量、Judd-Ofelt理论计算和阈值估算，分析评价了其作为激光材料的可行性。 3、针对纳米分散型介质具有一定程度的随机散射特征，用蒙特卡罗方法仿真研究了增益散射体中受激辐射和放大的工作机制。观察到当泵浦能量超过一定阈值时，散射体的整体辐射谱突然变窄，随着泵浦能量继续增大，光滑谱背景上出现分离尖峰。理论解释了出现这一现象的物理原因。进一步考察了散射体内空间分辨的辐射谱特征。 4、总结探索研究的进展与尚需解决的问题，提出进一步提高改进的建议。 |
| 英文摘要 | Since laser was invented 40 years ago, many kinds of laser materials, such as solid, liquid, gas, semiconductor and plasma, have been invented. Most of them, especially all-solid-state lasers, have developed greatly and been applied extensively. However, liquid laser material, except dye, has not been developed enough because of some technical problems and inherent limitations. In recent years, high average power and high energy lasers have developed rapidly because of promoting demand on many fields, such as laser weapon, laser fusion and laser machining. Thereinto, liquid laser has attracted researcher’s attention again because of its unique advantages, such as better heat management, smaller specific weight and scaling more easily. After reviewing the developing status of liquid laser home and abroad and analyzing the merits and faults of the existing technology routes, we draft the main subject of this thesis: to explore new Nd3＋-doped organic fluid laser materials, mainly including two kinds of systems－solutions and admixtures dispersed with nanoparticles. In the article, the technical requirements and technology routes of preparing the organic materials, the characterization of spectra and light loss, and the characteristics of stimulated emission in random media have been researched theoretically and experimentally. The practicability of the new systems are evaluated. Important progresses have been made in investigating new kind of fluid laser materials, which lays the foundation for new fluid lasers. Main contents of the thesis are summarized as follows: 1、Nd3+ -contained organic complexes and the organic solutions are prepared. The spectrum properties and light losses of these solutions are tested and studied in detail. Then the probabilities of the organic solutions as laser material are analyzed and evaluated through experiments and Judd-Ofelt calculations. 2、A new kind of Nd3+-doped fluid material, which is admixtures dispersed with nanoparticles, are put forward for the first time . The influences of particle parameters on scattering loss are researched through simulating light transporting in random media with Monte Carlo method. The results can help to decide the parameters of nanoparticles we need. Nanomaterial is prepared and then dispersed in organic solvent to form homogeneous fluid laser material. To overcome aggregation and sedimentation of the nanoparticles and obtain transparent fluid material with low scattering loss, the surfaces of Nd2O3 nanoparticles are modified firstly. Then the spectrum properties of the transparent dispersing system are measured and studied. The probabilities of the organic system as laser material are analyzed and evaluated through experiments and Judd-Ofelt calculations too. 4、The stimulated emission in amplifying random media are investigated using Monte Carlo simulation. The entire emission spectra of random media narrow abruptly when pumping energies exceed certain threshold values, and when the pumping energies further increase, distinct sharp peaks emerge on spectrum background . The explanation on these phenomena are given. The characteristics of emission spectra in random media are researched from the spatial point of view. 6、Finally, main results of the exploration and the remaining problems worth being further researched are summarized, and some advice on improving the materials given. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15321]  |
| 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 | 叶云霞. 新型流体激光介质的探索研究[D]. 中国科学院上海光学精密机械研究所. 2007. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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