Phase transition study of H:LiNbO3 waveguides by Raman spectroscopy

New results on Raman spectra of protonated LiNbO₃ are reported in order to clarify the structural and compositional changes in waveguide layers during proton exchange and post-exchange annealing processes. Samples with different degree of Li-H substitution exchanged in either neat or buffered benzoic and pyrophosphoric acid melts are investigated providing Raman and optical measurements simultaneously. The question of phase state of protonated layers at slow and rapid cooling after the annealing procedure is discussed. Qualitative and quantitative agreement between the structural data reported earlier for proton-exchanged powders and the Raman data obtained for protonated single crystals is established. A new band at 69 cm^–1 is observed which is strongly intensity dependent upon the hydrogen presence in waveguide layers. By using this band the degree of proton exchange is determined for different treatment conditions of the samples.     

质子交换铌酸锂光波导的红外吸收光谱

用尼高力 36 0型红外吸收光谱仪对用已二酸 (Adipicacid)和苯甲酸 (Benzoicacid)的不同摩尔比混合作为质子源进行质子交换制作的Z切铌酸锂光波导进行红外吸收光谱分析。表明 :OH-自由基团在 35 0 0cm-1处存在吸收峰 ,对应于质子交换中替代质子的特征 ,OH-氢键在 70 0cm-1处存在另一个吸收峰 ,对应于交换中的填充质子的特征。当两种不同的质子源以不同的摩尔比例混合时 ,质子源中的H 浓度不同 ,进行交换的速度也不同 ,结果导致在 35 0 0和 70 0cm-1两处的峰的强度发生变化。而这两个峰强度之比值可作为制作高质量铌酸锂光波导的重要依据 ,因此 ,对这两个峰的研究对制作高质量的铌酸锂光波导具有重要的意义     

LiNbO3质子交换波导及其退火效应

采用质子交换技术,以苯甲酸为交换源,实验研究X-切LiNbO₃质子交换平面波导及其退火效应。利用棱镜耦合器测出波导模折射率。采用费米函数,由模折射率确定出波导折射率分布随退火时间的变化关系,给出了分布参数和曲线.     

铌酸锂质子交换波导中切伦科夫倍频实验研究

报道了质子交换铌酸锂平板波导中切伦科夫倍频蓝绿光输出研究。理论上计算了质子交换波导参数对不同基波波长倍频转换效率的影响。制备出适合于蓝绿光输出的铌酸锂质子交换波导并观测到较高转换效率的倍频光产生,实验中我们测量了倍频转换效率与抽运动率以及抽运波长的关系,实验结果与理论预测吻合。     

Mössbauer study of proton-exchanged LiNbO3:Fe

Topotactic proton exchange (Li against H) can be achieved by treating LiBnO₃ with appropriate acids. In order to investigate the effect of proton exchange on Fe-impurities we studied LiNbO₃:Fe powder material treated in sulphuric acid and LiNbO₃:Fe single crystals treated in benzoic acid by Mössbauer spectroscopy. During the topotactic ion exchange only the Li-ions are exchanged for protons, whereas the Fe-impurities are retained in the material.     

Interpretation of liquid crystalline nature with statistical modeling of FTIR spectra

Analysis of paramorphosis in liquid crystalline materials remains challenging task analytical chemists. Analytical techniques like High performance liquid chromatography, Mass spectroscopy, dilatometric studies and infrared spectrometer were the most popular methods of choice for analysis. Application of infrared spectra in liquid crystalline materials is limited to room temperature in spite of its functional attribution in its formation. The anisotropic nature of proton donor supramolecular p-n-alkyl benzoic acid exhibiting nematic phase arises due to its chemical structure studied with infrared spectra. Infrared spectra are explored by computational technique to study its nature that provides new way of understanding for the prospective researcher. The appropriate technique is realized by principal component analysis in extraction of chemical information for homologous series of mesogen p-n-alkyl benzoic acid with n the alkyl chain length extending from pentl to decyl that exhibit nematic phase.     

1.5μm质子交换铌酸锂光波导TE0模偏振器

在１．５μｍ光波长，首次研制出质子交换铌酸锂光波导ＴＥ０模偏振器。器件由嵌在Ｔｉ扩散波导之间的一段质子交换波导构成，器件长度为２ｍｍ。实验测得，偏振器的消光比和带尾纤插入损耗分别为４２ｄＢ和４．３ｄＢ。     

Peculiar spin dynamics of the photoexcited triplet state of pentacene in a benzoic acid crystal: an ESE study

The spin dynamics of the photoexcited triplet state of pentacene in three host crystals: benzoic acid, naphthalene andp-terphenyl, were measured from 5 to 300 K by the electron spin echo technique following N₂ laser excitation. The triplet kinetics (population, spinlattice relaxation and decay rates) of pentacene in the benzoic acid (BA) hosts differ from those observed in the other two host systems. A model which includes a strong guest-host interaction and proton tunneling in the tautomerization of BA hosts is used to explain the observations.     

Proton beam writing of Nd:GGG crystals as new waveguide laser sources

Focused proton beam writing has been utilized to fabricate optical channel waveguides in Nd:GGG crystals. The 1?MeV proton beam irradiation creates a local modified region with positive refractive index changes at the end of the proton trajectory, in which the channel waveguide could confine the light field in a symmetric way. Room-temperature laser emission has been achieved at 1063.7?nm, with absorbed pump power of 61?mW (at 808?nm). The obtained slope efficiency of the Nd:GGG waveguide laser system is as high as 66%, which is, to our best knowledge, the highest value for integrated lasers from ion beam processed channel waveguide systems.     

ZnO：LiNbO3质子交换光波导层内应变的测定

报道了利用Ｘ射线双晶衍射法精确确定ＺｎＯ：ＬｉＮｂＯ３质子交换光波导的晶格常数变化，结果表明，波导层内含有均匀分布的三维应变场，晶格常数的变化随着波导取向的不同而呈现各向异性特点。     

Cycle time as a variable in CRAMPS NMR. Detection of minor impurities in solids to levels of ≤0.01 mol%

The use of varying multiple-pulse decoupling cycle times in homonuclear dipolar decoupling experiments with combined rotation and multipole-pulse spectroscopy proton nuclear magnetic resonance (NMR) is shown to be capable of quantitatively and qualitatively analyzing amounts of occluded residual liquid solvent, present as saturated solution, in some organic solids crystallized from solution. Lower limits of detection can be 0.01 mol%, as illustrated for the cases of durene,p-hydroxy benzoic acid, and adipic acid crystallized from ethanol, and alanine crystallized from water. Quantitative detection at this level depends upon the phase diagram of the system in question, and the ability to obtain a high-resolution proton NMR spectrum from that portion of the sample consisting of the occluded solvent impurity in the presence of a relatively large proton background from the probe. Determinations of spin diffusion may be used to infer the average size of the mobile domains containing the impurity. The variation of longitudinal relaxation time with temperature may be used as a check on the uniformity of saturated solvent occluded in the system studied. The classical case of using a cooling curve to detect the total amount of liquid protion remaining in the crystal after crystallization is discussed.     

TRANILAST ^1H^13CNMR谱分析及其结构的鉴定

本文用COSY,CHCOR等二维核磁共振技术对TRANILAST,2[]3-(3.4-二甲基苯基)1-氧代-2-丙烯基]氨基]苯甲到进行了~1H、~(13)C NMR谱数据分析及归属,并结合~(13)C弛豫时间T_1 及变温实验对合成产品进行了结构鉴定.     

Proton-exchanged optical waveguides fabricated by glutaric acid

In this paper, we first report that a new proton source, glutaric acid, has been used to fabricate optical waveguides in Z-cut lithium niobate crystals. The relationship was experimentally established between proton-exchanged (PE) waveguide parameters and fabrication conditions. It is shown that this new organic acid can be used to obtain deep PE waveguides in fast diffusion speed (0.275 μm²/h at 221°C) and with low loss (0.2 dB/cm). It provides an alternative approach for fabricating PE waveguides in lithium niobate substrate.     

系数倍率紫外光谱法同时测定复方苯甲酸软膏中的苯甲酸和水杨酸的研究

本文用系数倍率紫外光谱法同时测定了复方苯甲酸软膏中苯甲酸和水杨酸的含量,取得了满意的结果,苯甲酸测定回收率为99．33％－101．80％,水杨酸测定回收率100．92％－105．46％。     

苯甲酸与苯甲酸钠的太赫兹光谱和振动模式分析

采用太赫兹时域光谱技术测量了苯甲酸及其钠盐苯甲酸钠在8～115 cm-1的特征吸收光谱,分析总结了苯甲酸实测特征吸收峰的归属,并利用密度泛函理论对苯甲酸钠进行了结构优化和振动模式计算。结果表明：利用苯甲酸和苯甲酸钠在太赫兹波段的特征吸收谱完全可以辨识这两种性状相似的物质;导致苯甲酸钠和苯甲酸太赫兹特征吸收谱存在差异的根本原因是苯甲酸钠的离子键影响了分子内共价键的键长和原子间的键角以及其在晶胞内分子间的相互作用和排列组成;除了苯甲酸的107 cm-1和苯甲酸钠的54 cm-1 吸收峰,苯甲酸和苯甲酸钠的其余实测特征吸收峰均来源于分子的集体振动。     

质子交换的新型集成光学TM通偏振器的研究

提出了用扩钛和质子交换相结合的方法在x-切,y-传的LiNbO3 衬底上制成TM 通集成光波导偏振器的新方案, 即在扩钛波导两侧的适当位置引入锯齿形的质子交换区。用二维BPM法分析了这类新型偏振器的消光特性, 给出了质子交换区几何形状以及质子交换区与扩钛波导之间的间隙对TE波消光比的影响, 给出了数值分析结果, 并得到了优于23 dB的实验结果     

集成光学TM模偏振器的制作

用扩钛和质子交换相结合的方法在ｘ切ｙ传ＬｉＢｎＯ３衬底上制成了ＴＭ模集成光波导偏振器。质子交换区位于扩钛波导的末端两侧。在质子交换区域Δｎｅ〉０，Δｎ０〈０，因此ＴＥ模辐射进入衬底。偏振器工作于１．３μｍ波长，消光比优于４７ｄＢ，光纤０－波导－光纤插入损耗３．５ｄＢ。     

2.45 GHz ECR离子源的微波阻抗匹配

ECR离子源的等离子体阻抗对其微波传输与阻抗匹配设计至关重要。在中国科学院近代物理研究所现有的2.45 GHz ECR 质子源上,对等离子体阻抗进行了测量。首先用水吸收负载代替等离子体负载测量得到了所用微波窗阻抗,然后根据质子源测量数据,推算得到了等离子体阻抗。实验结果表明,脊波导输出端阻抗与后续负载不完全匹配,等离子体阻抗随微波功率变化呈非线性。这些结果为ECR离子源过渡匹配和微波窗的设计提供了参考依据。Plasma impedance of an ECR ion source is important for microwave transmission and impedance matching design. Plasma impedance was measured indirectly with the 2.45 GHz ECR proton source at the Institute of Modern Physics, Chinese Academy of Sciences. In the test, we got microwave window mpedance by using water absorption load instead of plasma load, and the source plasma impedance was derived from the test data with the 2.45 GHz ECR proton source and microwave window impedance. The experimental results show that ridge waveguide output impedance and the subsequent load does not exactly match, plasma impedance variation is nonlinear with microwave power. The achievedresult is useful in the design of ridged waveguide and microwave window.     

632.8nm波长质子交换光波导型偏振器的研究

在可见光域研制出钛扩散铌酸锂质子交换光波导偏振器，同时，给出波导偏振器参数测试装置。在理论上，利用物理光学和波导色散理论分析与计算了这种偏振器的消光比，分析了影响器件性能的各种因素，理论计算与实验结果符合良好。