Investigation on Raman spectra and thermal properties of LuVO4 and Nd:LuVO4 crystals

Lattice vibration modes of LuVO4 and Nd:LuVO4 crystals were calculated by using space group theory,and polarized Raman spectra were recorded with four different geometrical scattering configurations at room temperature to test the theoretical prediction and assign the normal vibrations of these crystals.The measured specific heats at 293.15 K were 0.368,0.378 and 0.363 J/(g·K) for LuVO4,2 at.% and 3 at.% Nd:LuVO4,respectively.The thermal diffusivities of Nd:LuVO4 crystals were obtained in the temperature ra...     

Microstructural characteristics of Nd:YAG powders leading to transparent ceramics

We reported on the successful synthesis of the Nd:YAG (Nd:Y3Al5O12) nano-powders by using urea as the precipitant with the microwave assisted homogeneous precipitation (MAHP) method. The different microstructural characteristics of the Nd:YAG nano-powders were affected by the concentrations of (Y3++Nd3+) and Al3+ ([Y3++Nd3+]=0.06 mol/L, [Al3+]=0.1 mol/L), aging time (6 d) and aging condition (in vessel). The optimum microstructural characteristics of the high quality Nd:YAG nano-powders leading to transparent Nd:YAG ceramics including the pure YAG phase, the smallest crystallite size, a uniform crystallite size distribution, less density defects, uniform micro-components and the proper molar ratio of (Y3++Nd3+) and Al3+ (0.6148) were discussed.     

紫外倍频晶体K2Al2B2O7的生长与性能

研究了溶液配比和降温速率对K2Al2B2O7(KABO)晶体生长的影响,发现NaF与KABO的适宜比例为2:1,晶体生长的合适降温速率为(0.1~5)℃/d,NaF为合适助熔剂.籽晶的取向也影响晶体的质量,[110]方向是KABO晶体生长的最佳生长方向;采用顶部籽晶技术,以NaF为助熔剂可生长出尺寸为50 mm×20 mm×17mm、重30 g的高光学质量KABO透明单晶.晶体对波长2500nm以上的光表现出各向异性吸收,紫外截止边为180nm.用V型棱镜法测出的KABO晶体折射率拟合出了Sellmeier方程,计算了SHG相位匹配范围,一类相位匹配最短倍频波长为225.5 nm.KABO晶体的266 nm SHG相位匹配角为58.1°.长度为3.6 mm的晶体Nd:YAG激光器四倍频输出能量转换效率为12.3％.     

Ca_4RO(BO_3)_3(R=Gd,Y)晶体空间方向的确定

介绍了高质量Ｃａ4ＧｄＯ（ＢＯ3）3（ＧｄＣＯＢ）、Ｃａ4ＹＯ（ＢＯ3）3（ＹＣＯＢ）晶体的生长，报道了两种晶体空间方向的确定方法；对于该类低对称性非线性光学晶体的实用化具有推动意义．     

锂质无光釉表面显微结构研究

分析了锂质无光釉表面显微结构与釉面光学特征的关系。认为良好的无光釉对表面的晶体形态、晶体大小和含量以及玻璃含量均有较严格的要求。在确定釉的配方后，关键是烧成工艺，控制好烧成温度和降温速率极为重要。成核剂的加入对形成理想的锂质无光釉表面显微结构反而不利。     

LGS晶体的化学腐蚀及缺陷分布

采用提拉法生长得到LGS单晶，采用磷酸作腐蚀刘，对LGS晶体做了一系列腐蚀实验。实验结果表明：对于不同方向晶面．腐蚀液的配比和腐蚀时间等条件各不相同。根据腐蚀坑可以判定．其极轴是二次轴[112^-0]方向．并可具体确定极轴方向。关于腐蚀坑的分布可以判定，在现行条件下生长的晶体具有较高的质量。     

Nd:YAG纳米粉体的制备与性能表征

以碳酸氢铵为沉淀剂，采用共沉淀法和添加分散剂的方式获得具有高烧结活性的碳酸盐前驱体，这种前驱体在较低温度下烧结即可转变成相。同时借助IR，XRD和TEM等测试手段对前驱体和YAG粉体进行表征。实验结果表明，在分散剂存在的情况下，于800℃左右煅烧2h，前驱物直接转变为纯的YAG相，而无其他的杂质相，所得YAG粉体的颗粒尺寸约20nm，单分散的形貌近似球形。此外，不同温度下烧结所得粉体的荧光性质表明，发光强度随着烧结温度的提高而增加。     

Spectroscopic properties of vacancies and trap levels in Lu3Al5O12：Ce^3＋ crystals

In order to study the spectroscopic properties of vacancies and trap levels in Lu₃Al₅O₁₂:Ce³⁺ (LuAG:Ce³⁺) crystal, the <111>-oriented LuAG:Ce³⁺ crystal grown in pure nitrogen atmosphere by Czochralski method was annealed in oxidizing atmosphere (air) and reducing atmosphere (H₂+N₂), respectively. The excitation and emission spectra of LuAG:Ce³⁺ crystal after different thermal annealing treatments were measured in the temperature range of 8?450 K, and the thermally stimulated luminescence curves of LuAG:Ce³⁺ crystal were characterized. It is found that the oxygen vacancies in LuAG:Ce³⁺ crystal are effectively eliminated through the annealing treatment in air and four trap levels are observed in as-grown LuAG:Ce³⁺ crystal with temperature position peaking at 110, 210, 325 and 475 °C, respectively.     

深紫外激光倍频新晶体KBe2BO3F2

综述了深紫外激光倍频新晶体KBe2BO3F2（KBBF）的结构、物理化学性能和非线笥光学性能；介绍了该晶体的原料合成方法、晶体生长技术、助熔剂体系的选择及晶体的宏观缺陷等研究工作及获得的进展；指出该晶体生长的主要困难是层状结晶飞性和自发成核数目的控制。     

Nd∶GdxLa1-xVO4 (x=0.8、0.6、0.45)晶体的制备和性能研究

报道了Nd∶GdxLa1-xVO4 (x=0.8、0.6、0.45)系列新型晶体的生长,并研究了它们的性能. 用中频感应提拉法生长了Nd∶GdxLa1-xVO4 (x=0.8、0.6、0.45)系列晶体.研究表明,随着La在晶体中含量的增加,晶体生长的难度逐渐增大. 测量了这三种晶体的结构和晶胞参数, 结果表明它们的结构仍为锆英石结构,随着La掺杂量的增加,晶胞参数逐渐变大. 测量了Nd∶Gd0.8La0.2VO4和Nd∶Gd0.6La0.4VO4晶体的吸收谱和荧光谱.随着La掺杂量的增加,在808.5 nm附近的吸收半宽增加.其发射波长没有明显的变化. 用LD抽运Nd∶Gd0.8La0.2VO4晶体,进行了发射波长为1.06 μm和1.34 μm的激光实验.在2.9 W的抽运功率下,获得了1.18 W的1.06 μm和671 mW的1.34 μm的激光输出(OC27)