Diode-Pumped Quasi-Three-Level Passively Q-Switched Nd：GGG Laser with a Codoped Nd,Cr：YAG Saturable Absorber

We demonstrate the first quasi-three-level passively Q-switched Nd：GGG laser at 937nm using a Nd, Cr：YAG crystal as the saturable absorber. The dependences of the average output power, the repetition rate and the pulse width on the incident pump power are obtained. A maximum average output power of 1.18 W with repetition rate of 35kHz and pulse width of 45ns is achieved at an incident pump power of 18.3 W. The corresponding optical-to-optical and slope efficiencies are 6% and 10%, respectively.     

Nd∶Y_3Al_5O_(12)单晶及纳米粉体的Raman光谱分析

测量了YAG（Y3Al5O12）/Nd∶YAG单晶、Nd∶YAG前驱物及其在不同温度下煅烧获得粉体的拉曼光谱,对谱峰的振动模式进行了指认,对结果进行了分析。Nd∶YAG前驱物在煅烧时,有一个由非晶态向晶态的转化过程;700℃下烧结前驱物获得非晶态产物的结构中含有AlO4四面体结构;随着煅烧温度的升高,拉曼光谱的变化主要表现在两个方面：一是谱峰半高宽（FWHM）减小,谱峰强度增大;二是一些拉曼光谱谱峰发生了频移,这是纳米多晶粉体的界面组元的有序度提高所致。另外,800℃下煅烧获得的Nd∶YAG纳米粉体的晶格振动模式与Nd∶YAG晶体的晶格振动模式存在差异,这是纳米多晶粉体的界面组元的贡献所致。     

化学计量比LiNbO_3晶体的激光显微拉曼光谱研究

对用助熔剂提拉法生长的近化学计量比LiNbO3晶体进行了激光显微拉曼光谱测试分析 ,与同成分LiNbO3晶体相比较 ,A1 (TO)与E(TO)模的谱线数目、频率基本不变 ,验证了LiNbO3晶体属置换式固溶体的结论 .738cm- 1 处拉曼振动峰 (A1 (LO)模 )的相对强度随晶体中Li2 O含量的增加发生了明显的变化 ,在两种掺杂晶体中 ,此振动峰已经消失 .根据Li空位模型 ,从占位和结构上进行了分析讨论 .在 15 2和 872cm- 1 处拉曼振动峰半高宽随晶体中Li Nb的增大而变窄 ,对二者关系进行了线性拟合 ,利用拟合公式可根据拉曼振动峰半高宽计算晶体中的Li Nb值 .     

Calculating Hamiltonian parameters for Yb~(3+) in a low-symmetry lattice site,and fitting the structure and levels of Yb~(3+) :TaO_4 (= Gd,Y,and Sc)

An iterative method is used to find the values of the Hamiltonian parameters for Yb3+ in a given low-symmetry crystalline site.Samples of Yb3+:RETaO4(RE = Gd,Y,and Sc) were prepared and their structures were determined.Based on the obtained structural data,their orbital-spin parameters and crystal field parameters were fitted by the superposition model(SM).Using the crystal field parameters obtained by the SM fitting as the initial parameters,the Hamiltonian parameters were fitted iteratively.The calculated and experimental energy levels for Yb3+:RETaO4 are consistent,and the maximal mean-root-square deviation is only 2.84 cm-1,indicating that the method is effective to determine the Hamiltonian parameters of Yb3+ in low-symmetry crystalline sites.     

Calculating Hamiltonian parameters for Yb^3＋ in a low-symmetry lattice site, and fitting the structure and levels of Yb^3＋ ：RETaO4 （RE = Gd, Y, and Sc）

An iterative method is used to find the values of the Hamiltonian parameters for Yb^3＋ in a given low-symmetry crys- talline site. Samples of Yb^3＋ ：RETaO4 （RE = Gd, Y, and Sc） were prepared and their structures were determined. Based on the obtained structural data, their orbital-spin parameters and crystal field parameters were fitted by the superposition model （SM）. Using the crystal field parameters obtained by the SM fitting as the initial parameters, the Hamiltonian parameters were fitted iteratively. The calculated and experimental energy levels for Yb^3＋：RETaO4 are consistent, and the maximal mean-root-square deviation is only 2.84 cm^- 1, indicating that the method is effective to determine the Hamiltonian parameters of Yb^3＋ in low-symmetry crystalline sites.     

Ce3+:YAG晶体位错的研究

本文报导了用中频感应加热提拉法生长Ce3+:YAG晶体,直径达45mm.对样品采用不同的化学试剂进行了时间不等的腐蚀,用偏光显微镜观察到不同形貌的位错蚀坑,分析了位错与晶体结构及生长工艺参数等因素之间的关系.     

热键合YAG/Nd:YAG复合晶体的透过光谱研究

本文在一定的温度和压力下,通过热键合技术,获得了YAG/Nd:YAG复合晶体.这种复合晶体在非吸收波段的光学透过率与通过一块相同厚度Nd:YAG晶体的光学透过率实验值以及理论值相一致.因此从透过率的角度,表明纯YAG晶体与Nd:YAG晶体间的键合区域为均匀过渡,基本上无散射界面存在,实现了一体化.     

BSO晶体的高温拉曼光谱与高温结构特征

阐述了BSO晶体在常温下的结构特征,通过测量晶体在常温下的拉曼光谱,对晶格主要振动模式进行了指认,测量晶体升温至熔化过程中不同温度下的拉曼光谱,分析研究了其微观结构在升温过程中的变化以及在高温状态下的结构特征。     

钒酸钇晶体中的颜色问题

本文以YVO4晶体生长过程中的V2O5挥发量与YVO4晶体颜色的关系为线索,研究了YVO4晶体颜色与YVO4晶体缺陷、光吸收特性的关系;结果表明晶体中的化学配比变量x影响了YV1-xO4-5x/2晶体颜色.x越大,V的含量越低,则晶体的颜色越浅,但与此同时因组分偏离化学配比而带来的晶体缺陷增多.所以不能无原则地减弱晶体颜色.适宜的x值为0～0.03.     

实时测量熔体法生长晶体固/液边界层结构的高温热台

根据水平区熔法晶体生长的原理,设计制作了激光显微喇曼高温热台;针对不同晶体,采用不同的加热装置,构成相应的温度场,并对其三维方向的温度场进行了测量.在工作温度为1500K时,控制精度为±0.1K.用该高温热台和激光显微喇曼光谱仪对接,对TeO2和BSO晶体在熔点温度下固液界面的激光显微喇曼光谱进行了实时测量.