飞秒激光辐射下微突起结构形成的超快热弹性模拟

本文结合有限元方法和超快热弹性模型对飞秒激光辐射下形成的微突起结构进行了数值模拟研究。模拟结果表明微突起结构的形成与入射飞秒激光的参数以及材料的热弹性质有关。在圆锥状微突起结构的形状和高度方面，实验结果与模拟结果呈现良好的一致性，这也从实验上表明了超快热弹性模型的有效性。本文的研究将有助于利用超快激光对薄膜材料进行纳米构造。

飞秒激光诱导铬膜产生周期性微结构

通过纳焦量级的飞秒激光在铬膜表面诱导出了周期性微结构,并使用入射飞秒激光和激发的表面等离子体波之间的干涉理论模拟分析了飞秒激光作用下铬膜表面的温度场分布情况,定性地解释了铬膜表面周期性微结构产生的机理。实验和理论结果有助于对飞秒激光和铬膜相互作用机制的理解。

Preparation and optical properties of Ag/PPy composite colloids

Ag/PPy (polypyrrole) composite colloids were prepared through the reaction of silver nitrate with pyrrole solution in DNIF either in the dark, or under the irradiation of femtosecond laser (fs) pulse or UV lamp. The UV-vis spectra of the nanocomposite colloid display an intense absorption band around 620 nm, accompanied by a weak one around 470 nm. The colors and optical absorption spectra of as-synthesized colloids can be reversibly tuned between blue and red, corresponding to absorption band of 620 urn and 526 urn, within few seconds by adding base and acid solutions or gases in turn into the composite colloid suspension. In addition, excess of H+ solution enhanced the absorption band around 470 nm and, at the same time, depressed that around 620 nm. The possible mechanism for the formation and optical absorption properties of the Ag/PPy composite colloid was proposed. (C) 2006 Elsevier B.V. All rights reserved.

飞秒激光辐照ZnO晶体

利用飞秒激光对ZnO晶体进行辐照，对辐照前后的晶体样品进行发光光谱及拉曼光谱检测。辐照后发光光谱的某些发光峰强度有明显增强，但未产生新的发光峰，表明没有新的缺陷结构产生，但晶体内锌空位、间隙位锌、间隙位缺陷浓度增加。拉曼光谱结果表明，辐照后ZnO晶体未产生相变，但随着辐照激光功率的增大，拉曼峰327 cm-1，437 cm-1强度明显减弱，表明在飞秒激光辐照作用下氧化锌的结晶程度下降。但574 cm-1峰值却随着辐照功率的增大而变大，分析表明该拉曼峰很可能是由于晶体内间隙位缺陷所致。同时实验过程中观察到飞

单束飞秒激光在氧化铝晶体中诱导自组装微米点阵

报道了单束飞秒激光在氧化铝晶体中诱导自组装微米点阵的有关研究进展。当单束飞秒激光被透镜聚焦到氧化铝晶体的内部某固定点， 微米点阵就在聚焦点的下方自动生成。我们发现能否产生自组装点阵和光束的聚焦点距离样品表面的深度有关。通过比较在氧化铝晶体和氟化钙晶体中能够产生点阵的深度，我们发现在氧化铝中较浅的位置即能诱导出点阵，而在氟化钙中则要求深度较深。具体的机理在文中进行了讨论。

Blue green emission from a Cu+-Doped transparent material prepared by sintering porous glass

A colorless transparent, blue green emission material was fabricated by sintering porous glass impregnated with copper ions. The emission spectral profile obtained from Cu+ -doped high silica glass (HSG) by 267-mn monochromatic light excitation matches that obtained by pumping with an 800-nm femtosecond laser, indicating that the emissions in both cases come from an identical origin. The upconversion emission excited by 800-nm femtosecond laser is considered to be a three-photon excitation process. A tentative scheme of upconverted emission from Cu+ -doped HSG was also proposed. The glass materials presented herein are expected to find application in lamps, high density optical storage, and three-dimensional color displays.

飞秒激光所致金纳米粒子析出的玻璃非线性吸收

依据Z-scan技术，使用波长532nm的纳秒脉冲，研究了通过聚焦的飞秒脉冲诱导并辅以热处理得到的金纳米粒子析出的玻璃的非线性吸收．观察到金纳米粒子析出的玻璃具有饱和吸收特性．根据局域场效应，对实验结果拟合，得到在接近表面等离子体共振激发情况下，金纳米粒子三阶极化率虚部分别为Imχm^(3)=5．7×10^-7esu．玻璃样品中金纳米粒子的非线性响应主要起源于热电子贡献。

Growth and spectroscopic characteristics of Yb : GSO single crystal

For the first time, a high optical quality 10 at.% Yb3+-doped gadolinium oxyorthosilicate laser crystal Gd2SiO5 (GSO) was grown by the Czochralski (Cz) method. The segregation coefficient of Yb3+ was studied by the inductively coupled plasma atomic emission spectrometer (ICP-AES) method. The crystal structure has monoclinic symmetry with space group P2(1)/c; this was determined by means of an x-ray diffraction analysis. The absorption spectra, fluorescence spectra and fluorescence decay curves of Yb3+ ions in a GSO crystal at room temperature were also studied. Then, the spectroscopic parameters of Yb:GSO were calculated. The advantages of the Yb:GSO crystal include high crystal quality, quasi-four-level laser operating scheme, high absorption cross-sections and particularly broad emission bandwidth (similar to 72 nm). The results indicated that the Yb:GSO crystal seemed to be a very promising laser gain medium in diode-pumped femtosecond laser and tunable solid state laser applications when LD pumped at 940 and 980 nm.

Preparation of crystalline beta barium borate thin films on Sr2+-doped alpha barium borate substrates by liquid phase epitaxy

Thin films of beta barium borate have been prepared by liquid phase epitaxy on Si2+-doped alpha-BaB2O4 (alpha-BBO, the high temperature phase of barium berate) (001) and (110) substrates. The results of X-ray diffraction indicate that the films show highly (001) preferred orientation on (001)-oriented substrates while the films grown on (110) substrates are textured with (140) orientation. The crystallinity of these films was found to depend on growth temperature, rotation rate, dip time and orientation of substrate. Growth conditions were optimized to grow films with (001) orientation on (001) substrates reproducibly. The films show second harmonic generation of 400 nm light upon irradiation with 800 nm Ti: Sapphire femtosecond laser light. (c) 2005 Elsevier B.V. All rights reserved.

飞秒激光烧蚀玻璃基质金属薄膜直写衍射光栅

提出了一种新的制备光栅的方法，利用800nm的飞秒激光扫描蒸镀在石英玻璃衬底表面的金薄膜，通过烧蚀金薄膜在衬底表面形成衍射光栅。用波长为532nm的激光照射光栅，测量其一级衍射效率，测得的衍射效率最高为6．98％。通过改变激光扫描速度、激光功率、光栅周期等实验参数研究其对制备的光栅的一级衍射效率的影响，结果表明，降低激光扫描速度，减小光栅周期，或增加激光功率都能提高制备光栅的一级衍射效率。

飞秒激光辐照K9玻璃引起的暗化和折射率变化

对不同辐照条件下近红外飞秒激光在K9玻璃内部诱导产生的暗化现象和永久性折射率改变进行了实验研究。通过辐照前后的显微镜图片、吸收光谱、电子自旋共振谱(ESR)以及激光衍射实验，分析了K9玻璃中暗化现象产生的微观过程，发现暗化是由诱导产生的空穴型色心引起的。暗化程度和折射率改变随激光强度、扫描速度、扫描行间距变化而变化。光致色心的形成与非线性电离有关。对折射率永久性改变进行了简单说明，其机理仍在探索中。

飞秒激光诱导玻璃功能微结构

玻璃是一种传统材料，通过利用外场对玻璃进行空间选择性的微结构调控，发挥微结构的协同效应、量子效应和干涉效应等，可以赋予玻璃高功能和全新性能。本文阐述了近年来发展迅速的飞秒激光与玻璃相互作用的特征，介绍了我们利用飞秒激光诱导折射率变化直写三维光波导、微光栅和光散射型光纤衰减器，进行活性离子（稀土、过渡和重金属离子）的价态操作及应用和发现的基于飞秒激光与玻璃非线性相互作用的偏振依赖的纳米光栅形成机制。

Preparation and optical properties of silicate glasses containing Pd nanoparticles

We report the space selective precipitation of Pd nanoparticles in Pd2+ -doped silicate glass by ultrashort laser pulses irradiation and further annealing. Absorption spectra, transmission electron microscopy, refractive index measurement and Z-scan technique demonstrated that metallic Pd nanoparticles were precipitated in the glass sample after irradiation by an 800-nm femtosecond laser and subsequent annealing at 600 degrees C. We discuss a refractive index change and nonlinear absorption that combines the precipitation of Pd nanoparticles. Crown Copyright (c) 2005 Published by Elsevier B.V. All rights reserved.

飞秒激光脉冲照射诱导含芴结构树脂共聚物结构变化及机理的研究

在室温下用聚焦的飞秒激光照射高折射率、低双折射的透明含芴结构树脂-对苯二甲酸乙二醇酯(PET)共聚物，探索飞秒激光制备高分子光学功能微结构的可能性。通过紫外-可见吸收光谱、红外光谱、电子自旋共振谱、光学显微镜、扫描电镜及透射电镜等分析手段，对该材料在飞秒激光照射后的结构变化及机理进行研究。结果发现：含芴结构树脂共聚物在飞秒激光照射后产生化学键断裂，生成未成对电子，并形成无定形碳；照射区在可见光区域的吸收增强；随激光能量密度的减少在激光会聚点附近诱导结构由慧尾状向单一细丝转变。演示了三维着色内雕。

近红外超快强激光在LiF晶体内空间选择性诱导产生色心

通过显微镜聚焦近红外超快强激光作用在垂直于激光束移动的LiF晶体样品上，在LiF晶体中连续地诱导产生色心。以一定的间隔．反复移动该激光束的焦斑可在LiF晶体内空间选择性地诱导产生稳定的色心区。测定了不同条件下形成的色心区的吸收光谱，结果表明用近红外超快强激光可在LiF晶体中诱导产生具有激光效应的色心。