高分子材料的准分子激光表面处理

设计了３０８ｎｍＸｅＣｌ准分子激光对高分子材料的表面处理系统,初步探讨了紫外激光处理高分子材料表面的物理和化学过程,用本实验装置对聚四氟乙烯材料进行表面处理,改进了材料的粘着性,测定了材料与水的浸润角和激光能量及激光点数的关系曲线。     

准分子激光在打标中的应用

报导准分子激光在打标中的应用。从实验上得到了３０８ｎｍ激光对一些有机高分子材料和金属材料打标记的阈值能量，并观察到某些材料表面在激光作用下发生的变化。最后介绍一台自己研制的微机控制的准分子激光打标机。     

激光用于兔毛表面改性的实验研究

使用 XeCl 准分子激光和 CO_2激光对兔毛纤维进行了表面改性研究。实验证明用这两种激光在空气中直接辐照兔毛都能改变纤维的表面形状,XeCl 激光更适合用于兔毛的表面改性。     

激光用于兔毛表面改性的实验研究

使用XeCl准分子激光和CO2激光对兔毛纤维进行了表面改性研究.实验证明用这两种激光在空气中直接辐照兔毛都能改变纤维的表面形状,XeCl激光更适合用于兔毛的表面改性.     

XeCl准分子激光对聚对苯二甲酸乙二酯的表面接枝改性

用XeCl准分子激光照射聚对苯二甲酸乙二酯 (PET)薄膜 ,并同时进行表面接枝 ,提高薄膜表面亲水性。研究了激光能量和脉冲次数对照射和接枝后PET薄膜表面亲水性的影响 ,对比了激光照射烧蚀和接枝薄膜的表面性质差异 ,并分析了激光照射和接枝后样品重量变化的影响因素 ,提出了一种新的接枝率计算公式     

准分子激光辐照对ZnO陶瓷变阻体导电性能的影响

研究了准分子激光辐照对ＺｎＯ陶瓷表面性能的影响,测量ＺｎＯ陶瓷在准分子激光作用前后的伏安特性变化,对准分子激光辐照前后ＺｎＯ陶瓷进行了ＸＲＤ、ＸＰＳ分析对比,分析了准分子激光对ＺｎＯ作用的机理。     

不锈钢材料的准分子激光打标

介绍了微机控制准分子激光打标系统并进行了不锈钢表面打标的研究。在不同激光能量密度下不锈钢表面发生不同的变化;通过对激光作用不锈钢表面温度的计算得出打标阈值,即不锈钢熔点温度所对应的激光能量密度;在阈值以上激光作用下不锈钢表面形成镜面,而在阈值以下则出现氧化层。温度计算表明,激光表面相互作用时温度变化（升温或冷却）速率达１０１０℃／ｓ,可形成非晶态。     

偏振激光诱导的薄膜表面周期性自组织结构

本文研究了激光诱导的周期性表面结构(LIPSS)在聚甲基丙烯酸甲酯(PMMA)薄膜表面的形成过程。在导电玻璃衬底上制备得到PMMA薄膜,经p偏振的XeCl准分子激光照射后形成周期性的褶皱结构。用原子力显微镜(AFM)观察发现,形成的褶皱结构周期具有纳米量级,且当引入外加电场时,褶皱形成所需的激光脉冲数减少到2。当外加电压增加到30V时,褶皱的周期间隔明显减小,LIPSS变得不可控,出现了柱状的自组织结构。与直接用准分子激光照射的薄膜样品相比,外加辅助电压的引入改变了PMMA样品表面褶皱结构形成的时间和周期大小,褶皱形成的内部驱动力也发生了变化。     

准分子激光与角膜组织的相互作用及在屈光矫正中的应用

准分子激光在屈光手术中获得了迅速发展，193nm的准分子激光刻蚀角膜表面，改变角膜表面的光学结构从而矫正屈光不正，而且由于其微小的力学和热效应，不会损伤邻近组织。本文研究了激光和生物组织的相互作用，定性确定了光斑与角膜表面粗糙度关系，定量分析了193nm准分子激光高斯光束的切削量与能量密度的关系，在此基础上，给出准分子激光应用到眼科治疗机中的原理图、屈光程度与激光消融量的关系和具体算法，最后通过PMMA板的实验验证，并已应用到临床，取得了良好的效果。     

LDS技术在印制电路板行业应用前景分析简

激光直接成型（LDS）技术,指利用激光将数字化的图形照射到高分子材料表面,通过对照射过的区域进行直接金属化,最终在高分子材料表面形成图案的技术。它可以在高分子壳体上直接形成金属化的图案。本文详细探讨了LDS4技术的原理、加工方法、应用方向、在印制电路板中的应用前景以及目前存在的应用缺陷。     

Dye-doped step-index polymer optical fiber for broadband opticalamplification

We report the development of a novel and simple technique for fabricating polymer optical fibers of good optical quality for special device applications. This technique aims at polymer fibers doped with various functional organic materials. On the basis of the technique, step-index polymer optical fibers doped with laser dyes have been fabricated. High-gain and high-efficiency optical amplification has been achieved in a Rhodamine B-doped polymer fiber with a low pump power of less 1 kW and pulse width 5 ns. Because a high dye concentration is used, the optimal wavelength range of optical amplification in this fiber is significantly red-shifted toward the center of the communication window (at 650 nm wavelength) of methyl methacrylate-based polymer optical fiber. The shift is from the originally 560 and 590 nm to presently 610 to 640 nm. We also present experimental results that show good photostability of the Rhodamine B-doped polymer fiber, compared with those recently reported in the improved polymer material systems. From the experimental observation, we identified the thermally induced bleach of dye molecules as the major contributing factor to the lifetime of our material system     

熔融拉锥技术在光纤耦合传输中的应用

为了实现光纤激光器和放大器系统中不同参量光纤的低损耦合,采用光纤拉锥方法来实现光纤连接。经过理论分析,在大数值孔径光纤传输到小数值孔径光纤时,采用光纤拉锥技术可以有效地提高传输功率。采用改造的大模光纤熔接机进行拉锥实验研究,精确控制拉锥时间、放电功率、步进量和步进速率可以获得不同的拉锥形状。采用光纤拉锥元件对标准单模光纤和大模场光纤进行耦合实验,得到纤芯内传输的耦合输出效率由之前的50%提高到85%,获得了低损连接效果。结果表明,熔融拉锥技术为不同光纤之间的耦合提供了一种简单实用的方式。     

Tapered polymer single-mode waveguides for mode transformation

This paper presents a tapered polymer waveguide structure for coupling light between optical waveguides with differing geometries. Optical fibers, lasers, and other photonic integrated circuit components can be coupled with tapered waveguides. The polymer waveguide performs a mode transformation between different mode shapes and sizes. For example, the mode transformation can be from an elliptical laser diode mode to that of a circular optical fiber mode. The input and output of a tapered waveguide structure are analyzed, for the case of laser to fiber coupling, in order to determine the effect of misalignments on the coupling efficiency. Adiabaticity in waveguide propagation is discussed. The fabrication of our polymer waveguides is also described     

毫秒/纳秒激光致碳纤维环氧树脂损伤形貌研究

为了研究碳纤维环氧树脂在不同脉宽激光辐照下的损伤形貌,采用全自动变焦测量技术进行了实验验证,测量了碳纤维环氧树脂在毫秒/纳秒脉冲激光辐照下,损伤面积、损伤深度以及损伤形貌随激光能量密度的变化。结果表明,在毫秒脉冲激光作用下,材料损伤区域中心会产生一定的温度积累,损伤区域有一定的热效应,出现熔融、热解等现象,当激光能量密度为20.5J/cm2时,材料的损伤深度达到了47.3μm,材料表面析出的碳化物的高度为157.1μm,损伤深度以及表面碳化物的高度都随着能量密度的增大而增大;在纳秒激光作用下,光斑周围有明显的热反应区域,当能量密度大于47.3J/cm2时,表面的热反应区尤为明显,损伤面积随激光能量密度的增大明显增大,由于作用时间较短,损伤主要为表层损伤;树脂热解的气体向外膨胀,导致纤维结构断裂。研究结果为激光对碳纤维环氧树脂的损伤效果提供了实验依据。     

High Power Fiber Bundle Array Coupled LDA Module

1 Introduction High power laser diode arrays (LDA) have many advan- tages such as small volume, long working life, high slope efficiency and high optical density, so they have many applications in medical treatment, material pro- cessing, and for the pumping source of solid laser and etc. But unfortunately, the LDA can not be easy to use directly in these fields because of their poor beam quality and extremely asymmetric divergent beams (!x≈ 5°～10°and !y≈20°～35°, for example), so it …     

Simultaneous compensation of laser chirp, Kerr effect, anddispersion in 10-Gb/s long-haul transmission systems

The effects of chirp and fiber nonlinearity in a directly modulated 10-Gb/s intensity-modulated direct-detection (IM-DD) fiber transmission system are investigated by simulation, and a simple and flexible technique for compensating these effects is discussed. Self-phase-modulation (SPM) in optical fiber can be equalized by an anomalous dispersion fiber, whereas pulse broadening caused by laser transient chirp can be compensated by normal dispersion. Using these characteristics, laser transient chirp, SPM, and fiber dispersion can be simultaneously compensated by equalizing fibers inserted within certain intervals. Optimum compensation is always realizable for such fixed equalizing fibers, since the magnitude of SPM can be controlled by changing the optical power in the fiber. Simulation suggests that this technique enables 10-Gb/s, 100-km fiber transmission by direct modulation     

Controlled Sub‐Micrometer Hierarchical Textures Engineered in Polymeric Fibers and Microchannels via Thermal Drawing

The controlled texturing of surfaces at the micro‐ and nanoscales is a powerful method for tailoring how materials interact with liquids, electromagnetic waves, or biological tissues. The increasing scientific and technological interest in advanced fibers and fabrics has triggered a strong motivation for leveraging the use of textures on fiber surfaces. Thus far however, fiber‐processing techniques have exhibited an inherent limitation due to the smoothing out of surface textures by polymer reflow, restricting achievable feature sizes. In this article, a theoretical framework is established from which a strategy is developed to reduce the surface tension of the textured polymer, thus drastically slowing down thermal reflow. With this approach the fabrication of potentially kilometers‐long polymer fibers with controlled hierarchical surface textures of unprecedented complexity and with feature sizes down to a few hundreds of nanometers is demonstrated, two orders of magnitude below current configurations. Using such fibers as molds, 3D microchannels are also fabricated with textured inner surfaces within soft polymers such as poly(dimethylsiloxane), at dimensions and a degree of simplicity impossible to reach with current techniques. This strategy for the texturing of high curvature surfaces opens novel opportunities in bioengineering, regenerative scaffolds, microfluidics, and smart textiles.     

High-Quality Flat-Top Micromachining of Silica by a CW CO2 Laser

This letter demonstrates a simple and fast technique that dramatically improves the micromachined surface quality of silica substrates processed by a continuous-wave CO₂ laser. When sufficient laser power is directed at the surface of a sample, its temperature increases beyond the boiling point. Melted material is ejected and a groove is created. Some of the ablated material redeposits on each side of the groove, altering the surface quality of the substrate. To circumvent this problem, we deposit a polymer overlay as a sacrificial film which protects the surface during the ablation process, resulting in a flat surface on either side of the groove at very high writing speeds. The grooves can be used as an aid to passive alignment for an optical fiber, as diffractive optical elements or to create high-quality microfluidic chips     

Highly Symmetric Optical Fiber Tapers Fabricated With a CO2 Laser

This letter presents a simple technique that improves the symmetry of tapered fibers fabricated with a continuous-wave CO₂ laser. The uniform heat distribution inside an optical fiber is achieved by using a nonscanning dual-spot laser beam which applies heat on two sides of the optical fiber simultaneously. In so doing, highly symmetric tapers are obtained with an ellipticity close to unity. These tapers can be used as low-loss and polarization-dependent loss optical fiber filters or other optical devices such as symmetric fibers lenses     

Measurement of propagation constants related to material properties in high-bandwidth optical fibers

The material contribution to group index and material dispersion were measured in high-bandwidth graded-index optical fibers. A shuttle-pulse technique provided measurements of group index with precisions and accuracies of 0.1 and 0.2 percent using 5 m lengths of optical fiber. Material dispersion in fibers was measured over the0.8-0.9 mum wavelength region using different wavelength, short-pulse laser diodes. The influence of material dispersion on fiber bandwidth measurements was evaluated for laser diode sources. Limitations arising from source linewidth were experimentally determined from measurements on a fiber with high microbending enhanced bandwidth.