新型深紫外非线性光学晶体KBe_2BO_3F_2族的研究进展

深紫外非线性光学晶体KBe2BO3F2(KBBF)发展至今,已有将近20年的历史。首先简单回顾了KBBF化合物的发现、晶体生长以及基本光学性质,同时对KBBF族(MBe2BO3F2,M=K,Rb,Cs)的其它化合物如:RbBe2BO3F2和CsBe2BO3F2的晶体生长和其基本光学性质进行了报道,然后对这些新晶体产生深紫外谐波光输出的能力做了评估,最后介绍了利用KBBF晶体器件产生的深紫外相干光源在先进仪器等方面的应用。     

福建物构所发现新型无铍深紫外非线性光学晶体材料

正深紫外激光由于波长短、加工精度高的优点,在半导体光刻、激光光电子能谱仪和激光切割等方面具有重要应用。目前,KBe_2BO_3F_2(KBBF)是唯一能实际输出深紫外激光的非线性光学(NLO)晶体,但是,KBBF含剧毒铍元素且其晶体层状生长习性严重。因此,急需探索新型深紫外NLO晶     

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。     

我科学家发现一种新型光学晶体

《自然》杂志以《中国藏匿的晶体》为题，用3页篇幅对中科院理化技术研究所陈创天院士率领的团队发现并生长出一种最新的光学晶体——氟代硼铍酸钾（KBBF）晶体进行了详细报道，并称“中国实验室成为这种具有重大科学价值的晶体的唯一来源，它表明中国在材料科学领域实力日益增强”。KBBF晶体是目前唯一可直接倍频产生深紫外激光的非线性光学晶体，是在非线性光学晶体研究领域中，     

我国成功研制国际领先真空紫外激光角分辨光电子能谱仪

由中国科学院物理研究所和理化技术研究所共同攻关和研制的真空紫外激光角分辨光电子能谱仪获得成功。中国科学院综合计划局和基础科学局在京召开了“超高能量分辨率真空紫外激光角分辨光电子能谱仪”成果鉴定会。专家组一致认为，该项仪器使用KBBF非线性光学晶体和通过棱镜耦合PCT专利技术实现激光倍频产生的真空紫外激光，在国际上首次成功地应用于高分辨角分辨光电子能谱仪上。     

一种非线性光学晶体材料相匹配区间蓝移方案

<正>非线性光学晶体是通过频率转换拓宽固态激光器输出波段的关键材料。随着激光微加工,激光通讯和现代科学仪器的持续发展,对紫外/深紫外非线性光学晶体的需求日益增加。但是,很多拥有宽的紫外透过范围和大的倍频效应的晶体因其双折射无法满足深紫外相匹配而无法输出深紫外激光。中科院新疆理化技术研究所光电功能晶体材料实验室科研人员在深入分析了自主研发生长的非线性光学晶体氯硼酸钾KBOC(K3B6O10Cl)后,基于计算模拟,提     

紫外、深紫外非线性光学晶体的最新进展

深紫外相干光源对于光刻技术、光电子能谱仪、激光精密机械加工等均具有十分重要的意义.本文将系统地阐述可产生深紫外谐波光输出的非线性光学晶体是如何被发现的,这些晶体的基本线性、非线性光学性质和使用它们产生深紫外谐波光的方法.最后还简单介绍深紫外谐波光的几个典型例子.     

紫外、深紫外非线性光学晶体的最新研究进展

深紫外相干光源对于光刻技术、光电子能谱仪、激光精密机械加工等均具有十分重要的意义。本文系统地阐述了可产生深紫外谐波光输出的非线性光学晶体的发现、基本线性、非线性光学性质，以及用它产生深紫外谐波光的方法。最后简介了深紫外谐波光的几个实例。     

LD抽运355nm连续紫外激光器

报道了一台LD端面抽运Nd:YVO4晶体的内腔三次谐波转换的全固态连续紫外激光器.在谐振腔内,1064 nm的基频波经Ⅱ类相位匹配KTP晶体进行二倍频产生532 nm波长激光,二者再经Ⅰ类相位匹配LBO晶体进行和频获得355 nm紫外激光输出.在Nd:YVO4晶体的外端镀1064 nm/532 nm双波长高反膜作为输入镜,其与输出镜构成平-凹腔结构,并考虑到Nd:YVO4晶体所产生的热透镜效应,对腔长进行了详细的分析计算.当LD抽运功率为3W时,获得4.2 mW连续运转的355nm紫外激光.     

Nd:Zn:LiNbO_3单晶的生长及其抗光伤性能与光谱的研究

选择掺Zn作为Nd:LiNbO_3晶体的抗光伤手段,成功地生长了高掺Nd(原料中掺入1mol％的Nd_2O_3)的Nd:Zn:LiNbO_3单晶,根据其各种光学性能的测试结果,断定它是可用于半导体激光器泵浦的自倍频激光材升。测试晶体的双折射梯度及不同光斑直径下的消光比证明,晶体具有良好的光学均匀性。测试晶体中OH~-离子伸展振荡的红外吸收峰的位置发现,在Nd:LiNbO_3晶体中,Zn含量的抗光伤阈值为2.58wt％(以ZnO计)。对Zn含量超过抗光伤阈值的晶体测定了Ar~+离子激光(514.5nm)长时间辐照前后双折射的变化,为10~(-5)量级,证明掺Zn具有显著的抗光伤效应。晶体在可见光及近红外的吸收峰即为Nd~(3+)离子的5个本征吸收峰,较单掺Nd的LiNbO_3晶体,吸收峰的位置皆稍红移,其中基态~4I_(9/2)至~4F_(5/2)的跃迁吸收峰位于808nm,使得有可能在将该材料用于激光运转时采用半导体激光器为泵浦光源。晶体室温下的荧光谱与单掺Nd的晶体相近,最强峰为~4F_(3/2)向~4I_(11/2)的跃迁,谱线波长1.085μm(π偏振)与1.093μm(σ偏振)。能实现自倍频的为σ偏振的激光振荡,自倍频后输出波长0.546μm。用于倍频1.06μm的Nd:YAG激光,该晶体的相匹配温度为70～80℃,相匹配角80°左右。在室温下,正入射时,即非严格相匹配的条件下,晶体有10％左右的倍频转换效率     

VLE data for CO2-CF2Cl2, N2-CO2, N2-CF2Cl2 and N2-CO2-CF2Cl

Knowledge about vapour-liquid (VLE) is required as a basis of reliable calculations for separation processes. Correlations available for the prediction of T, p, x, y data are less accurate for mixtures at high pressures and mixtures containing supercritical components. The results of VLE experiments are reported and compared with data calculated with equations of state.     

Preparation of ZrO2-CeO2 and HfO2-CeO2 nanopowders

We prepared weakly agglomerated powders of ZrO₂-CeO₂ and HfO₂-CeO₂ solid solutions 5–8 nm in particle size, consisting of monoclinic and tetragonal phases. After heat treatment at 1200°C, the crystallite size was 30 and 14 nm, respectively. We also examined the effect of precipitate freeze drying on the crystallization of hafnia-based solid solutions containing up to 20 mol % CeO₂.     

Thermal diffusion in binary mixtures H2-CCl2F2 and H2-CHClF2

Thermal diffusion coefficients were measured in two gaseous mixtures, in which one component was close to the critical temperature, in the pressure range (19.6–127.4)·10⁴ N/m² and at a freon concentration of 0.25–0.8.     

Comparison of the Electronic Structures of La2CuO4, Sr2CuO2Cl2, and Sr2CuO2F2

First-principles cluster calculations are reported of the local electronic structure of the three compounds: La₂CuO₄, Sr₂CuO₂Cl₂, and Sr₂CuO₂F₂. The copper ${\text{3d}}_{x^2 - y^2 } $ and the planar oxygen 2p _σ atomic orbitals exhibit a similar degree of covalency. The out-of-plane orbitals, however, are quite different with the ${\text{3}}d_{3z^2 - r^2 } $ atomic orbital lowered significantly in energy for chlorine and fluorine apical positions.     

Radial GRIN glasses in Li2O-Na2O-Al2O3-TiO2-SiO2 systems

A series of GRIN glass rods have been developed in Li2O-Na2O-Al2O3-TiO2-SiO2 systems. Negative radial refractive index profiles were generated by exchanging Na+ for Li+ ions in these glass rods. It has been observed that TiO2 plays a vital role in increase in the profile depth and maximum change in the refractive index because of its ambivalent nature. Change in the refractive index can be further increased by increasing the concentration of exchanging cation in the base glass.     

Elastic and Electronic Properties of Superconducting CaPd 2 As 2 and SrPd 2 As 2 vs. Non-superconducting BaPd 2 As 2

The first-principles calculations were performed to predict the elastic and electronic properties of the superconducting ThCr₂Si₂-type phases CaPd₂As₂ and SrPd₂As₂ in comparison with the non-superconducting CeMg₂Si₂-type phase BaPd₂As₂. Besides, the same properties were compared for CeMg₂Si₂- and ThCr₂Si₂-type polymorphs of BaPd₂As₂. We found that all these phases are mechanically stable and belong to soft materials with low hardness. The near-Fermi region is formed by the valence states of the blocks [Pd₂As₂] with decisive contributions of Pd 4d states. The values of N(E _F) increase in the sequence: CaPd₂As₂ < SrPd₂As₂ < BaPd₂As₂, i.e. in the reverse sequence relative to the transition temperatures T _C. Thus, the change in T _C cannot be explained by the electronic factor, i.e. by the simple correlation T _C～N(E _F). Most likely the decrease in T _C in the sequence CaPd₂As₂ → SrPd₂As₂ and the absence of a superconducting transition in BaPd₂As₂ are related to the structural factors and the peculiarities of the electron–phonon coupling mechanism.     

Si_2N_2O-Al_2O_3-La_2O_3和Si_2N_2O-Al_2O_3-CaO系统的亚固相关系

本文给出了 Si_2N_2O-Al_2O_3-La_2O_3和 Si_2N_2O-Al_2O_3-CaO 系统的亚固相图。实验结果表明:在 Si_2N_2O-Al_2O_3-CaO 系统中有一个未知结构的新化合物 CaO·Si_2N_2O,在3CaO·Si_2N_2O 和3CaO·Al_2O_3两化合物之间形成连续立方固溶体。而 Si_2N_2O-Al_2O_3-La_2O_3系统中则没有发现新化合物。在两个系统的富 Si_2N_2O区,过量的 Si_2N_2O 与 La_2O_3和 CaO 分别反应形成 Si_3N_4与 La_(10)[SiO_4]_(?)N_2(H-相)(和 CaSiO_3。所研究的这两个三元系统中,分别形成了如下几个四元相容性区。在 Si_2N_2O-Al_2O_3-La_2O_3系统内有:H-Si_3N_4-La_2O_3·Si_2N_2O-La_2O_3·Al_2O_3;H-Si_3N_4-La_2O_3·Al_2O_3-La_2O_3·11 Al_2O_3;H-Si_3N_4-La_2O_3·11 Al_2O_3-Al_2O_3;H-Si_3N_4-Al_2O_3-O′s.s;H-Si_3N_4-O′s.s-Si_2N_2O在 Si_2N_2O-Al_2O_3-CaO 系统内有:Si_3N_4-CaSiO_3-CaO·Si_2N_2O-3CaO·Al_2O_3;Si_3N_3-CaSiO_3-3CaO·Al_2O_3-2CaO·Al_2O_3·SiO_(?);Si_(?)N_(?)-CaSiO_3-2CaO·Al_2O_3·SiO_2-Al_2O_3;Si_3N_4-CaSiO_3-Al_2O_(?)-O′s.s;Si_3N_4-CaSiO_3-O′s.s-Si_(?)N_(?)O