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chi20181127上海光机所胡丽丽557450Laser materials are the basis of laser technology development, as it is described to be “one generation of materials, and one generation of technology”. Rare-earth active material is a main kind of laser material. It has been widely used in all solid-state lasers. Nd3+/Yb3+ co-doping, as a potential way to increase the pumping efficiency of Yb3+, was suggested in 1964, which is close to the first Ruby Laser in the world invented by Maiman in 1960. Today, the interest on Nd3+/Yb3+ co-doping is to combine the features of Nd3+ and Yb3+ ions to develop some potential applications. Potential applications of Nd3+/Yb3+ co-doping include laser applications, solar cell as well as up-conversion, and among them laser application is a hot topic. Until now, a large amount of research work has been reported in laser application, however most of them just investigated the sensitization of Nd3+ to Yb3+ and its spectral characteristics. This research method and research idea are single. Obviously, it is not conducive to a correct understanding of the emission properties of Nd3+/Yb3+. According to the existed few reports, the lasing feature of Nd3+/Yb3+ is quite different from the emission feature that obtained from fluorescence. It is very difficult to rely solely on Nd3+→Yb3+ energy transfer to improve laser performance. In fact, Nd3+/Yb3+ co-doping also includes new content such as the sensitization of Yb3+ to Nd3+, temperature and pumping methods. In order to catch up with the demand of laser technology, it is necessary to carry on a systematic, multi-angle and theoretical research work on Nd3+/Yb3+ co-doping. Based on the research conditions of our lab, the aim of this dissertation is to explore the lasing properties of Nd3+/Yb3+ co-doped glass fiber. This dissertation consists of six chapters, followed by: Introduction; Spectral characteristics of Nd3+/Yb3+ co-doped glass; Lasing properties of Nd3+/Yb3+ co-doped phosphate glass fiber; Lasing properties of Nd3+/Yb3+ co-doped silica glass fiber; Dual-wavelength fiber lasers; Conclusion and Outlook. In Chapter I, a brief introduction of the characteristics of and research background of Nd3+/Yb3+ co-doping were given. In addition, a literature classification of Nd3+/Yb3+ was made. Based on it, a comment on the achievements and the existing problems of Nd3+/Yb3+ co-doping was made; thus it generates the research contents of this dissertation. In Chapter II, methods of spectral measurement (e.g. fluorescent spectrum, lifetime, time-resolved emission spectrum and Raman spectrum) and theory calculation were adopted to study the spectral characteristics of Nd3+/Yb3+ co-doped phosphate glass around the energy transfer efficiency and Nd3+?Yb3+ energy transfer mechanism, in order to deepen the understanding of the sensitization phenomenon between Nd3+ and Yb3+and be convenient for the discussion in the following laser situation. In addition, the spectral characteristics of Nd3+/Yb3+ co-doped fluorophosphate glass/silica glass were investigated. In Chapter III, laser properties of a Nd3+/Yb3+ co-doped phosphate glass fiber were studied by using 808 nm and 970 nm LD as pumping source to study the role of energy transfer at the situation of laser operating with different pumping case. In the process of analyzing energy transfer, testing method of temperature-dependence fluorescent spectrum and ASE were introduced. Experiment results indicated that Nd3+→Yb3+ energy transfer caused by 808 nm pumping will be suppressed by the lasing of Nd3+, thus the lasing characteristics of the fiber seems like a Nd3+ doped fiber. However, when it comes to 970 nm pumping case, Yb3+→Nd3+ energy transfer will lead to the lasing of Nd3+ at 1053 nm, which is a temperature raising phenomenon during the increase of 970 nm pump power as revealed by temperature-dependence fluorescence. Under dual-laser pumping at 808 nm and 970 nm, optical-power tunable dual-wavelength fiber laser at 1036 nm & 1053 nm was achieved in a 0.8 meter long fiber. In Chapter IV, lasing properties of Nd3+/Yb3+ co-doped silica glass fibers were studied in detail, with the advantages of fiber devices in compacting lightpath and data collection. Positive results in gain bandwidth, laser efficiency, thermal laser property and photodarkening were achieved in the Nd3+/Yb3+ co-doped fiber. A theory model to calculate the lasing properties of Nd3+/Yb3+ co-doped fiber with dual-laser pumping (e.g. at 808 nm and 975 nm) was established, which has been succeeded to explain the mechanisms of gain bandwidth tuning and laser efficiency increasing around 1 micrometer. In Chapter V, phenomenon of the 1036 nm & 1061 nm dual-wavelength laser (DWL) occurring in Nd3+/Yb3+ co-doped silica glass fiber, with dual-laser pumping at 808 nm and 975 nm, were studied. The following researches were down: variation of laser spectrum/output power of the 1036 nm & 1061 nm DWL vs. 808 nm pumping power; wavelength tuning property of DWL; influence of temperature on the laser spectrum of 1036 nm & 1061 nm DWL; theoretical calculation model of DWL; and watt-level all-fiber 1036 nm & 1061 nm DWL. In Chapter VI, a conclusion for this study was made; some suggestions for further study were given.2018atalunwen21812821646229Nd3+/Yb3+ co-doping; energy-transfer suppressing effect; broad gain bandwidth; 1 μm dual-wavelength fiber laserStudy for laser properties of Nd3+/Yb3+ co-doped glass fiberNd3+/Yb3+共掺玻璃光纤的激光特性研究正如“一代材料,一代技术”所述,激光材料是支撑激光技术发展的基础。稀土离子掺杂材料是一类重要的激光材料,在当今固体激光器中占有相当大的比重。历史上,人们在1964年就提出了Nd3+/Yb3+共掺的概念——作为一种增大Yb3+抽运效率的潜在方案,它与Maiman在1960年发明的世界上第一台红宝石激光器同属一个时期。目前Nd3+/Yb3+共掺的研究目的旨在融合两稀土离子的特点开展拓展性研究工作,研究方向涉及激光应用、太阳能电池和上转换发光。激光应用方向一直是Nd3+/Yb3+共掺光谱研究的热点,至今已有大量的文献报道,但绝大部分都只是关注Nd3+对Yb3+的敏化及其光谱特点。研究方式和研究思路单一,显然这不利于正确认识Nd3+/Yb3+的发光特性。从少量涉及激光的研究报道来看,Nd3+/Yb3+共掺在激光层面下的发光特点显著区别于荧光层面,单纯依靠Nd3+→Yb3+能量传递来提升激光性能是十分困难的。事实上,Nd3+/Yb3+共掺还包含Yb3+敏化Nd3+、温度以及抽运方式等新内容。为适应激光技术的发展要求,有必要对Nd3+/Yb3+共掺开展系统性、多角度和理论化的研究工作。基于本实验室的研究条件,本论文的目的是探索Nd3+/Yb3+共掺玻璃光纤的激光特性。 本论文包含六个章节,依次为:引言;Nd3+/Yb3+共掺玻璃的光谱性质;Nd3+/Yb3+共掺磷酸盐玻璃光纤的激光特性;Nd3+/Yb3+共掺石英玻璃光纤的激光特性;双激光波长光纤激光器;结论与展望。 论文第一章,对Nd3+/Yb3+共掺的特点及其研究的历史背景进行了简述,对有关Nd3+/Yb3+共掺的研究报道进行了归类总结,并就现有的研究成果以及存在的问题进行了提炼与分析,进而提出本论文的研究内容与思路。 论文第二章,利用荧光、寿命、时间分辨、Raman以及理论计算等手段,围绕Nd3+?Yb3+能量传递效率和传递机理,对Nd3+/Yb3+共掺磷酸盐玻璃的光谱性质进行了重点探讨,以深化对敏化现象的认识,同时也便于后文激光情形的讨论与分析。此外,对Nd3+/Yb3+共掺氟磷酸盐和石英玻璃的光谱性质也进行了探究。 论文第三章,以808 nm和970 nm LD为抽运源,结合不同的抽运方式对Nd3+/Yb3+共掺磷酸盐玻璃光纤的激光特性进行了实验探究,以评估能量传递在激光产生中扮演的角色。在能量传递的分析过程中,引入了ASE和变温荧光光谱的测试手段。实验结果表明:在808 nm抽运下,Nd3+的受激辐射对Nd3+→Yb3+能量传递具有抑制作用,这使得此时共掺光纤的激光特性等同于Nd3+掺杂玻璃光纤;在970 nm抽运下,Yb3+→Nd3+能量传递能致使Nd3+在1053 nm产生激光。变温光谱实验表明,这是一个温升效应;在808 nm和970 nm双波长抽运下,从0.8 m长的光纤中获得了功率大小可调谐的1036 nm & 1053 nm双波长光纤激光。 论文第四章,借助光纤器件在紧凑光路和数据采集上的优势,对Nd3+/Yb3+共掺石英玻璃光纤的激光特性进行了深入探索。在增益带宽、激光效率、耐热性和光暗化四个方面都获得了正面结果。通过建立双波长抽运情形下的速率模型,对增益带宽的调谐现象和激光效率的增大现象给出了理论计算说明。 论文第五章,对808 nm和975 nm双波长抽运下出现的双波长激光现象进行了系统研究,它们包括:双波长激光的运行状态(等振幅和波长切换)以及功率变化与P808之间的关系;双波长激光的波长调谐;温度对双波长激光的影响;双波长激光的理论描述;瓦级全光纤化1036 nm & 1061 nm双波长光纤激光器。 论文第六章,对本论文的研究工作进行了总结,并给出下一阶段工作的建议。Nd3+/Yb3+共掺;能量传递抑制现象;宽增益;1μm双波长光纤激光中国科学院上海光学精密机械研究所林治全材料学博士
中文题目: Nd3+/Yb3+共掺玻璃光纤的激光特性研究
外文题目: Study for laser properties of Nd3+/Yb3+ co-doped glass fiber
作者: 林治全
导师姓名: 胡丽丽
学位授予机构: 中国科学院上海光学精密机械研究所
答辩时间: 20181127
Nd3+/Yb3+ co-doping; energy-transfer suppressing effect; broad gain bandwidth; 1 μm dual-wavelength fiber laser
学位级别: 博士
正文语种: chi
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