四钼酸钆钡晶体的制备与光谱性能研究

发布时间：2018-06-27 15:24

本文选题：激光晶体 + 晶体生长　；参考：《暨南大学》2017年硕士论文

【摘要】：LD泵浦的全固态激光器具有高效率、结构紧凑等优点,开展适合于LD泵浦的高效新型激光晶体研究仍然是近年激光材料领域的热点。在新材料研究中,四钼酸钆钡晶体具有高度的无序性,可以提高掺杂稀土的离子浓度,展宽掺杂离子的吸收与发射光谱,具有良好的物理与化学稳定性,有很好的商用价值。本文主要研究内容包括下面几个部分:1.系统地分析了钼酸盐类作为激光晶体的研究现状和发展前景,指出四钼酸钆钡(BaGd_2(MoO_4)_4)晶体研究的必要性和研究目的。2.分别对Nd/Yb共掺和Yb/Tm共掺四钼酸钆钡(BaGd_2(MoO_4)_4)晶体进行了生长技术研究。首先使用高温固相法对两类晶体进行多晶原料高温固相合成,然后通过单晶提拉法(CZ法)生长出了两类单晶体并进行了冷加工。3.对两类晶体的理化性能进行了系统表征。使用X射线衍射分析技术(XRD)对晶体结构进行了指认,并得到其晶格参数,表明所生长的晶体为类白钨矿结构的BaGd_2(MoO_4)_4晶体,属于单斜晶系,点群结构为C2/c。使用ICP-AES分析法测试了晶体中所掺杂稀土离子的浓度,并计算了其分凝系数。使用热重-差示热扫描分析技术对晶体的热学性质进行表征,得到BaGd_2(MoO_4)_4晶体的熔点为1070℃,且TG曲线为一条平滑的直线,说明其在高温状态下理化性质稳定。4.对两类晶体的光谱性能进行了系统的研究。使用紫外-可见-近红外分光光度计测量了Nd/Yb:BaGd_2(MoO_4)_4和Yb/Tm:BaGd_2(MoO_4)_4晶体的吸收光谱,计算了其吸收截面,并基于J-O理论,计算了稀土离子Nd~(3+)、Tm~(3+)的J-O强度参数、自发辐射跃迁几率、荧光分支比与辐射寿命,并对两对Nd/Yb和Yb/Tm稀土离子之间的能量传递过程进行了分析。通过对两类稀土离子共掺杂的晶体进行荧光光谱测试,表明了掺杂10at.%Nd~(3+)/10at.%Yb~(3+):BaGd_2(MoO_4)_4晶体的荧光峰强度明显弱于掺杂浓度为5at.%Nd~(3+)/10at.%Yb~(3+):BaGd_2(MoO_4)_4晶体,并且随着Nd~(3+)浓度的升高其辐射寿命逐渐降低。而对于Yb/Tm:BaGd_2(MoO_4)_4晶体的荧光光谱分析表明,在1809 nm发射峰处,其发射带宽为176 nm,并随着Yb离子掺杂浓度的升高,其发光相对强度逐渐增强,表明该类晶体具有1.8μm可调谐激光输出的潜能。
[Abstract]:The LD pumped all solid state laser has the advantages of high efficiency and compact structure. It is still a hot spot in the field of laser materials to develop a new type of high efficiency laser crystal suitable for LD pump in recent years. In the study of new materials, four gadolinium molybdate crystal has a high degree of disorder, which can increase the ion concentration of doped rare earth and broaden the absorption of doped ions. The absorption and emission spectra have good physical and chemical stability and have good commercial value. The main contents of this paper include the following parts: 1. the research status and development prospect of molybdic acid salts as laser crystals are systematically analyzed. The necessity and purpose of the study on the study of the crystal of barium gadolinium (BaGd_2 (MoO_4) _4) are pointed out and the purpose of the study is.2. points. The growth technology of Nd/Yb co adulterated with Yb/Tm Co doped with four gadolinium molybdate (BaGd_2 (MoO_4) _4) crystals was studied. First, high temperature solid phase synthesis of polycrystalline materials was carried out by high temperature solid-phase method. Then two kinds of single crystals were grown by single crystal drawing (CZ method) and the physical and chemical properties of two kinds of crystals were processed by cold processing.3.. The X ray diffraction analysis (XRD) is used to identify the crystal structure and obtain its lattice parameters. It shows that the crystal is BaGd_2 (MoO_4) _4 crystal of the structure of scheelite and belongs to the monoclinic system. The point group structure is C2/c. using ICP-AES analysis to test the concentration of rare earth ions doped in the crystal and calculate the concentration of the doped rare earth ions in the crystal. The thermal properties of the crystal are characterized by thermogravimetric differential thermal scanning analysis. The melting point of BaGd_2 (MoO_4) _4 crystal is 1070, and the TG curve is a smooth straight line. It shows that the physicochemical properties of the crystal at high temperature are stable and.4. has a systematic study on the spectral properties of the two kinds of crystals. The absorption spectra of Nd/Yb:BaGd_2 (MoO_4) _4 and Yb/Tm:BaGd_2 (MoO_4) _4 crystals were measured by the near-infrared spectrophotometer, and the absorption cross sections were calculated. Based on the J-O theory, the J-O strength parameters of the rare earth ions Nd~ (3+), Tm~ (3+), the spontaneous emission transition probability, the fluorescence branch ratio and the radiation life, and the two pairs of rare earth ions and the rare earth ions were calculated. The energy transfer process between two kinds of rare earth ions Co doped crystals is tested by the fluorescence spectra. It is shown that the fluorescence peak intensity of the doped 10at.%Nd~ (3+) /10at.%Yb~ (3+): BaGd_2 (MoO_4) _4 crystal is obviously weaker than the doping concentration is 5at.%Nd~ (3+) / 10at.%Yb~ (3+), and the concentration increases with the concentration. The radiation life of the Yb/Tm:BaGd_2 (MoO_4) _4 crystal has been gradually reduced, and the fluorescence spectrum analysis of the crystal shows that the emission bandwidth of the 1809 nm emission peak is 176 nm, and the relative intensity of the luminescence increases with the increase of the doping concentration of the Yb ions, indicating that the crystal has the potential of 1.8 u m tunable laser output.
【学位授予单位】：暨南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O734;TN244

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