Ti:Mg:LiNbO3晶体的折射率和高效室温倍频

本文测量了Ti:Mg:LiNbo3晶体的折射率,给出了色散方程,演示了该晶体的高效室温倍频。在声光调制下,1.064μm到0.532μm激光辐射的倍频转换效率达50%。     

偏振光调制的扫描近场光学显微镜应用

本文利用电光调制技术结合反射式扫描近场光学显微镜，获得了可以对光的偏振方向进行调制的针尖发光远场接收反射光的近场显微镜。对原有的Topometrix Aurora NSOM系统作了较大的改进。采用音叉(tuning fork)检测光纤探针与样品间的剪切力取代了原有的光学法振动检测，避免了杂散光干扰。观察了(Ba0.5Sr0.5)TiO3薄膜和LiTaO3晶体表面的电畴结构。横向分辨率约为50nm。观察说明，反射式扫描近场光学显微镜适合研究固体表面的电畴结构，可获得光学衬度较好的电畴分布图像。与形貌图像相比电畴与形貌无关。     

LiNbO3单晶再展新颜

文章指出:用二元一组分(Li/Nb=48.45/51.55mol％)或三元一致熔体组分(Li/Nb=47.2/52.8mol％)容易生长成组分均匀的优质单晶。单晶的光折变效应是由于一致组分的V~(5-)_(Nb)和Nb~(4 )_(Li)及其复合缺陷以及Fe、Ar等杂质的引入而形成的。一致熔体组分的单晶之光损伤阈值低于富锂组分单晶的光损伤阈值。     

Fe：LiNbO3晶体的生长及其多波耦合效应

报道了Ｆｅ：ＬｉＮｂＯ３晶体的生长。测试了晶体的放大率，指数增益系数，衍射效率相位共轭反射率和响应时间；对Ｆｅ：ＬｉＮｂＯ３晶体的光折变机理进行探讨。     

光折变晶体Ce：LiNbO3的光学性质及其应用

本文介绍了Ce:LiNbO_3晶体的光学性质,并与Fe:LiNbO_3晶体作了对比,同时用该晶体做了相衬法有关实验。     

铌酸锂晶体铁电畴电极化反转结构的ESEM观察

用高压电场实现铁电晶体电畴的极化反转，制备极化方向周期性反转的非线性晶体人工微结构是实现准相位匹配的有效方法。扫描电镜常用于观察刻蚀处理后的铁电畴和畴反转光栅的结构，而环境扫描电镜ESEM可对绝缘样品进行直接观察，因而是本研究的更为有效手段。     

Ti,Mg:LiNbO3晶体的腔内倍频

本文首次报导提拉法生长的钛-镁共掺铌酸锂晶体(Ti,Mg:LiNbO3)用于Q开关Nd:YAG激光器1.064μm辐射的腔内双通倍频,获得了61%的能量转换效率。     

Ce：Fe：LiNbO3晶体的生长及二波耦合效的研究

本文介绍了Ｃｅ：Ｆｅ：ＬｉＮｂＯ３晶体的生长，测试了晶体的二波耦合指数增益系数和衍射效率，它具有很高的指数增益系数和衍射效率，并且具有温度增强效应。     

纳米材料的几种扫描探针显微表征方法

扫描探针显微镜（SPM）作为一种广泛应用的表面表征工具,不仅可以表征三维形貌,还能定量地研究表面的粗糙度、孔径大小和分布及颗粒尺寸,在许多学科均可发挥作用.以纳米材料为主要研究对象,综述了国外最新的几种扫描探针显微表征技术,包括扫描隧道显微镜（STM）、原子力显微镜（AFM）和近场扫描光学显微镜（SNOM）等方法,展示了这几种技术在纳米材料的结构和性能方面的应用.     

飞秒激光刻写z切LiNbO3晶体形成通道光波导

在z切LiNbO3晶体上进行飞秒激光刻写通道光波导的实验研究.利用光学显微镜研究了光波导的微观结构;在633 nm波长下,端面耦合得到光波导的近场光强分布,波导区为飞秒激光聚焦的区域,TE和TM偏振下都形成了光波导模.研究了激光扫描速度和脉冲能量对刻写质量的影响,结果发现,激光脉冲能量在2.0μJ左右、扫描速度在0.6...     

Scanning force microscopy studies of GaAs films grown on offcut Ge substrates

The surface morphology of GaAs films grown on offcut Ge substrates is studied using a scanning force microscope (SFM). We investigated the effects of the Ge buffer layer, growth temperature, film thickness, and prelayer on the GaAs surface morphology. The starting Ge substrates are offcut 6° toward the [110] direction to minimize single steps on the substrates before molecular beam epitaxial film growth. We find that comparing with GaAs samples grown without Ge buffer layers or with unannealed Ge buffer layers, samples with annealed Ge buffer layers are much smoother and contain no antiphase boundaries (APBs) on the surface. For thick (≥1 μm) GaAs films with an annealed Ge buffer layer, the surfaces display crosshatch lines and elongated mounds (along , which are associated with the substrate offcut direction. As the film thickness increases, the crosshatch lines become shorter, denser and rougher, and the mounds grow bigger (an indication of GaAs homoepitaxial growth). We conclude that annealed Ge buffer layers are crucial for growing high quality GaAs films with few APBs generated during the growth. In addition, under optimal conditions, different prelayers make little difference for thick GaAs films with annealed Ge buffer layers.     

Controlled Ablation of Langmuir–Blodgett Films Made by Scanning Force Microscopy

In this paper we present results concerning the development of a lithographic technique suitable for application to Langmuir–Blodgett films. Controlled ablations of well-defined portions of the film have been made by using a scanning force microscope (SFM). We report the values of the microscope operational parameters that have allowed us either to perform non-destructive imaging or to obtain reproducible ablations of controlled depth. In particular, our analysis has pointed out the importance of the scanning speed in giving rise to such surface modifications. © 1997 John Wiley & Sons, Ltd.     

扫描近场光学显微镜中探针样品间距控制方法

在动态原子力与近场光学扫描显微镜中,探针与样品的间距关系到分辨率以及扫描速度这两个最重要参数的性能。在对几种主要的动态原子力/扫描近场光学组合显微镜的探针/样品间距控制模式分析的基础上,认为提高探针Q值是提高扫描显微镜分辨率的有效方法。但是,对采用检测控制探针振幅模式,期望在提高分辨率的同时加快扫描成像速度是不可实现的,因而限制了其发展的空间。而在检测控制探针频率模式下,提高探针Q值,可有效提高扫描探针显微镜的分辨率,且不会制约扫描成像速度的提高。该结论为将来的纳米操作和纳米超高密度光存储的实用化提供了可能,对大连理工大学近场光学与纳米技术研究所研制的原子力与光子扫描隧道组合显微镜(AF/PSTM)的改进和产业化具有积极意义。     

飞秒激光在LiNbO3晶体上烧蚀衍射光栅

利用脉冲宽度为50 fs,中心波长为800 nm,重复频率为1000 Hz的乜秒激光脉冲在LiNbO3晶体上烧蚀表面衍射光栅,采用632.8 nm的He-Ne激光测量不同光栅的衍射效率.在激光脉冲能量和光栅常数相同的情况下,烧蚀速率由20 μm/s增大到200 μm/s时,所加工光栅的1级衍射效率从1.7%增大到2.3%;如果光栅常数和烧蚀速率不变,将激光脉冲能量由70 nJ增大到110 nJ,所加工光栅的1级衍射效率从1.9%减小到1.3%;随着光栅常数的增大,在LiNbO3晶体上烧蚀光栅的各级衍射效率也随之增加.对实验结果进行理论分析表明,可以通过提高烧蚀速率、降低激光脉冲能最和增大光栅常数来提高飞秒激光加工光栅的衍射效率.     

Universality of Polarization Switching Dynamics in Ferroelectric Capacitors Revealed by 5D Piezoresponse Force Microscopy

Ferroelectric polarization switching is sensitively affected by phenomena on multiple length scales, giving rise to complex voltage‐ and time‐controlled behaviors. Here, spatially resolved switching dynamics in ferroelectric nanocapacitors are explored as a function of voltage pulse time and magnitude. A remarkable persistence of formal macroscopic scaling laws for polarization switching based on classical models down to nanoscale volumes is observed. These observations illustrate the persistence of the return point memory in the material and allow the thermodynamic parameters of defects controlling switching to be estimated.     

激光扫描显微镜的探讨

本文探讨在满足象素密度要求的条件下,充分利用电视监视器可分辨光点数,具有大扫描视场的激光扫描显微镜的设计。     

磁控溅射法在LiNbO3衬底上制备ZnO薄膜及性能研究

采用磁控溅射法在(001)LiNbO3衬底上制备了ZnO薄膜,并对其进行了退火处理.利用X射线衍射仪(XRD)、紫外一可见光谱仪和光致发光谱(PL)对ZnO薄膜的结构和光学性能进行了分析.结果表明,ZnO薄膜具有(002)的择优取向,退火后ZnO薄膜的(002)衍射峰的强度增强,半高宽减小,(002)峰向高角度方向移动.退火后样品可见光透过率增加,光学带隙发生红移.退火后的样品,紫外发光峰强度增强,可见光发光峰强度相对减弱.     

Characterization of Geoinspired and Synthetic Chrysotile Nanotubes by Atomic Force Microscopy and Transmission Electron Microscopy

Geoinspired synthetic chrysotile nanotubes both stoichiometric and 0.67 wt % Fe doped were characterized by transmission electron microscopy and electron diffraction. Bending tests of the synthetic chrysotile nanotubes were performed using the atomic force microscope. The nanotubes were found to exhibit elastic behaviour at small deformations (below ca. 20 nm). Young's modulus values of (159 ± 125) GPa and (279 ± 260) GPa were obtained from the force‐deflection curves using the bending equation for a clamped beam under a concentrated load, for the stoichiometric and the Fe doped chrysotile nanotubes, respectively. The structural modifications induced by Fe doping altered the mechanical properties, with an apparent dependence of the latter on the number of constituting walls of the nanotubes.