Nd^(3+):Gd_3Ga_5O_(12)晶体的室温吸收光谱和荧光光谱(英文)

用提拉法生长了掺钕的钆镓石榴石 (Nd3 + :GGG)激光晶体。研究了室温下的吸收光谱和荧光光谱性质 ,分析了Nd3 + :GGG晶体4F3 / 2 →4I11/ 2 能级跃迁与 1.0 6 μm附近的荧光谱线之间的关系。吸收系数、发射系数、荧光寿命分别是 4 .32× 10 -2 0 cm-2 ,2 .3× 10 -19cm-2 ,2 4 0 μs,比较了Nd3 + ∶GGG和Nd3 + ∶YAG的物理参数 ,实验表明 :Nd3 + ∶GGG较Nd3 + ∶YAG有一系列的优点。

Nd^3＋：Gd3Ga5O12透明陶瓷纳米粉体的制备及光谱性能的研究

采用溶胶-凝胶法合成了用于Nd：Gd3Ga5O12（GGG）透明激光陶瓷的多晶纳米粉体，并利用XRD、SEM、荧光光谱分析对所得的GGG纳米粉体进行了分析。XRD分析结果表明：样品属于体心立方的晶体结构，随着温度的升高，粉体的晶化程度也相应提高，衍射峰强度增强，宽度减小，说明粉体粒径逐渐长大；SEM观察发现，获得了单分散、形状规则、似球形的GGG纳米粉体，且随着烧结温度的提高前驱粉体粒度不断增加。1000℃，12h是形成Nd：GGG纯相的较好的温度和烧结时间；荧光发射的最强峰位于1．06μm处，是Nd^3＋的^4I3/2→^4I11/2能级跃迁导致的荧光发射。溶胶-凝胶法制得的Nd：GGG粉体是比较均匀的，粒度较小的，纳米级的晶粒，有利于透明的陶瓷烧强，因此是比较合适的透明陶瓷前驱原料。

Synthesis and Spectral Properties of Nd^(3+)∶Gd_3Ga_5O_(12) Nanopowder for Transparent Laser Ceramics

Nd^3＋： Gd3Ga5O12（Nd ： GGG） nanopowder for transparent laser ceramics was synthesized using sol-gel method. XRD, SEM, and fluorescence spectrum were used to study the properties of Nd^3＋ ：Gd3Ga5O12 nanopowder. XRD patterns of samples show that it has a cubic structure. Meanwhile, pure Nd：GGG crystals were obtained at 1000 ℃ for 12 h. SEM photographs show that dispersed, uniform, ball-like Nd：GGG nanopowder is obtained. Both XRD and SEM results show that the crystallization degree and the grain size increase with the increase in calcining temperature. Analysis of fluorescence spectrum shows that fluorescence emission occurs at 1062.7 nm, which is the result of Nd^3＋ （^4F3/2→^4I11/2） transition. Homogenous Nd ： GGG nanopewder with a small grain size synthesized using the sol-gel method is favorable for sintering the transparent ceramic, which proves that the nanopewder obtained is suitable as a precursor for preparing GGG transparent ceramics.

Spectroscopy and Energy Transfer in Yb^(3+) and Tm^(3+) Co-doped Gd_3Ga_5O_(12) Crystal

Yb3＋/Tm3＋ co-doped Gd3Ga5O12 single crystal with a dimension of Φ30mm×20mm was grown successfully by Czochralski method.The absorption spectrum was recorded at room temperature and used to calculate the absorption cross-section.Based on the Judd-Ofelt（J-O） theory,we obtained the three intensity parameters and spectral parameters of this crystal,such as the line strengths,oscillator strengths,radiative probabilities and radiative lifetimes as well as the fluorescent branching ratios.Room temperature fluorescence spectra and luminescence decay curves were recorded.The energy transfer between Yb3＋-Tm3＋ was observed and the mechanism was discussed.The stimulated emission cross-section of the 3F4→3H6 transition was calculated by the Füchtbauer-Ladenburg（F-L） equation.The potential laser gains for this transition were also investigated.This crystal is promising as a tunable infrared laser crystal at 2.0 μm.

Spectroscopic investigations of Gd_3Sc_2Ga_3O_(12) garnet doped with Cr^(3+) and Nd^(3+) ions

Absorption, excitation and emission spectra as well as decay time measurements at 10, 77, and 300 K were perfumed for Gd3Sc2Ga3O12 garnet single-crystal doped with Cr^3＋ and Nd^3＋ ions. Strong reabsorption of Cr3＋ emission by Nd3＋ absorption lines was ob- served. The assignments of f-f and d-d transitions were proposed. The broad emission band of chromium ions is an indication that weak/intermediate crystal field strength is present at the Cr3＋ site.

Nd^(3+):Gd_3Ga_5O_(12)激光晶体的吸收与发光

测量了用提拉(CZ)法生长的Nd3+:Gd3Ga5O12(Nd:GGG)激光晶体室温时的吸收光谱,其中在806 nm处的吸收系数最大(α=5.12 cm-1),吸收截面为4.03×10-20cm2。用806 nm激发分别得到室温和10 K时的荧光光谱和荧光寿命,其中在1.06μm附近晶体的荧光发射强度最强,2种温度时的峰值发射截面分别为1.7×10-19cm2和1.9×10-19cm2。0.6 at%和1.0 at%2种Nd3+掺杂浓度的晶体,室温时的荧光寿命分别为251μs和240μs,10 K温度时分别为253μs和241μs。与Nd:YAG晶体的荧光寿命、浓度猝灭效应和发射截面进行了比较,对结果进行了分析与讨论。

制备Nd^(3+):Gd_3Ga_5O_(12)透明陶瓷的纳米粉体

由于激光晶体的生长周期长、成本高等缺点,激励人们不断地探索新的激光材料。透明陶瓷就是最近发展起来的一种。采用溶胶-凝胶法合成了用于制备掺钕的钆镓石榴石(Nd3+∶Gd3Ga5O12)透明激光陶瓷的多晶纳米粉体。采用X射线衍射(XRD)和扫描电子显微镜(SEM)对样品的晶相和形状进行了分析。结果表明,温度为1000℃,灼烧12 h,获得单分散、形状规则、似球形的Gd3Ga5O12(GGG)纳米粉体,且随着烧结温度的提高前驱粉体粒度不断增加。荧光发射的最强峰位于1062.7 nm处,对应于Nd3+的4F3/2→4I11/2能级跃迁。

Preparation of Nd-doped gadolinium-gallium garnet laser ceramic powder by sol-gel method

Preparation of Nd3+:Gd3Ga5O12 polycrystalline material by sol-gel method was preparated in this paper.The structure and the pattern of the sample were analyzed by thermogravimetric analysis and differential thermal analysis（TG-DTA）,Infrared spectrum,XRD,TEM and electron spectrum,which indicated that the powder with good characteristics of 70-100 nm can be obtained by sintering at 1 000℃.It was shown that the chemical composition of the sample was agreed with experimental requirements by electron spectrum analysis.

Nd:GGG晶体折射率和折射率温度系数的测量

利用自准直法，在303～443K温度范围内，用0．473、0．633、1．064、1．319和1．338μm等波长测量了Nd^3＋：Gd3Ga5O12（Nd：GGG）晶体的折射率，得到了上述波长的折射率温度系数和测量温度范围内修正的Sellmeier方程的常数。用色散方程和折射率温度系数表达式，计算了相应温度下在0．473～1．338μm波段内任意波长的折射率及折射率温度系数。