飞秒激光空间选择性调控玻璃中金属纳米粒子形成的研究
文献类型：学位论文
| 作者 | 曾惠丹 |
| 学位类别 | 博士 |
| 答辩日期 | 2004 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 干福熹 |
| 关键词 | 飞秒激光 热处理 硅酸盐玻璃 金属纳米粒子 光学非线性 |
| 其他题名 | Space-selective precipitation of metallic nanoparticles in glasses induced by femtosecond laser irradiation |
| 中文摘要 | 金属（Au，Ag等）纳米粒子掺杂的玻璃具有高的三阶光学非线性系数、超快非线性光响应等特点，是近年光学功能材料研究的热点。此类玻璃有望用作兆兆赫（THZ）量级的超快全光开关。已有大量的研究有关纳米粒子掺杂玻璃的制备方法和特性，但传统的熔融法、溶胶一凝胶、离子交换和离子注入等方法不能很好地控制材料内部纳米粒子的空间和尺寸分布。而材料内部纳米粒子的可控排列和尺寸分布对实现光电集成器件至关重要。另一方面超快超强的飞秒激光在材料三维微结构的制备和材料显微改性方面显示了独特优势，并已被用来制备光波导、光存储、光栅、光藕合器和光子晶体等三维光功能微结构和器件。本研究利用飞秒激光与玻璃的相互作用，成功实现了金属纳米粒子在玻璃内部空间选择性析出。论文分以下三个部分：一是使用飞秒激光辐照和热处理相结合，在掺杂金属离子的硅酸盐玻璃内部，诱导金属（Au，Ag）纳米粒子的空间选择性析出；二是研究不同辐照源、热处理温度、辐照条件、二次飞秒激光辐照和玻璃外加剂对金属纳米粒子析出（尺寸和分布）的影响。分析和讨论金属纳米粒子的析出机理；三是研究飞秒激光直接扫描和干涉法制备金属纳米粒子析出调制的相位光栅，根据衍射效率计算折射率变化，讨论分析折射率改变的原因，并通过Z-scan测试和光限幅实验，研究金属纳米粒子掺杂玻璃的光学非线性特性。论文工作取得了一系列定性和定量的结果，概括如下：使用钦宝石飞秒激光诱导和热处理相结合，在含有金属离子的硅酸盐玻璃内部，成功实现了有空间选择性的金属纳米粒子的析出。提出了金属纳米粒子析出机理是源于激光与玻璃的非线性相互作用导致金属离子还原，金属原子在后续的热处理过程中聚集长大成金属纳米粒子。研究了不同激光诱导条件和热处理温度对金属纳米粒子析出的影响。热处理温度升高、激光功率密度增大或激光辐照时间延长均引起金属纳米粒子尺寸增大。由此，通过改变激光诱导条件或热处理温度可以控制所析出的金属纳米粒子的尺寸，获得不同的纳米效应。飞秒激光辐照诱导析出的金属纳米粒子在室温下长期稳定，与纳米粒子相关联的显色具有持久性。用Z-scan技术和光限幅实验，观察到玻璃中Au纳米粒子的饱和吸收特性和光限辐特性。改变飞秒激光诱导参数可调节该含Au纳米粒子玻璃的光学非线性。讨论了不同辐照源（X射线、纳秒（ns）脉冲激光和飞秒（fs）脉冲激光）对诱导金纳米粒子析出的影响，发现辐照能降低金属纳米粒子析出所需的热处理温度，而且能改变金属纳米粒子的尺寸和分布。发现二次辐照对已形成的纳米粒子具有形状修饰甚至“擦除”作用。研究了硅酸盐玻璃中某些氧化物组份对金属纳米粒子形成的影响。结果表明少量氧化铅的引入能改变玻璃网络结构，抑制飞秒激光辐照后空穴捕获型色心生成，促进光诱导产生的金原子的移动和纳米粒子的形成和长大。少量Al203可抑制银纳米粒子析出，A12O3引入使玻璃内部银纳米粒子析出需要更高的热处理温度。使用相干的飞秒激光和后续的热处理，在含Au、Ag离子的玻璃中，实现了Au、Ag纳米粒子在几十微米的微区内周期性析出。Au、Ag纳米粒子沉积所形成的微结构的最小周期为～500nm，最小线宽为～150nm。通过改变激光诱导条件和干涉光路设计，一次性制备了含Au纳米粒子的双全息微光栅，并可控制双全息微光栅大小和两者之间的距离。这种方法可望在光电集成器件中用作光开关、微光栅以及光子晶体的制备等。根据测量飞秒激光直扫法和干涉法制备的光栅的衍射效率，计算了折射率变化，讨论分析了光致折射率改变的原因。对于飞秒激光直扫辅以热处理诱导的纳米粒子光栅，按照相位光栅衍射效率和折射率变化量关系，得到了折射率变化量～10-4的结果；对于相干的飞秒激光辅以热处理诱导的纳米粒子薄光栅，得到的折射率变化量约为10-1。两者之间呈现显著大的折射率变化量差别。其机理尚待进一步研究。 |
| 英文摘要 | Glasses doped with metallic nanoparticles have attracted considerable attention for their ultrafast nonlinear response and large third-order nonlinear susceptibility. They are expected to be promising materials for ultrafast all-optical switches in the tera-hertz (THZ) region. Many studies have been carried out on fabrication and characteristion of nanoparticle-doped glasses, but it's difficult to control the spatial and size distribution of nanoparticles in materials by the traditional fabrication method such as melting-quenching, sol-gel, ion exchange and ion implanting etc. For the applications in integrated optoelectronics, a well-defined assembly and spatial distribution of nanoparticles in materials is essential. Femtosecond laser (fs) pulses have shown predominant advantage in the space-selective microscopic processing and formation of the three-dimension (3D) modified microstructures. In addition, various kinds of integrated functional opto-devices including 3D optical waveguide, optical memory, grating, coupler, photonic crystal and so on have been fabricated by the fs laser processing. In this dissertation, metallic nanoparticles were space-selectivly precipitatied inside silicate glasses by fs laser irradiationa and successive heat treatment. The content of this dissertation consists of three parts. The first part involves the experiment of three dimensionally precipitation of gold (silver) nanoparticles in Au3+(Ag+)-doped silicate glasses by the fs laser irradiation and further heat treatment; The second part is investigation on the influence of irradiation resource, heat treatment temperature, irradiation and re-irradiation conditions, and the glass additives on the precipitation behaviors of nanoparticles. The possible precipitation mechanism of nanoparticles in the glasses is also discussed. The content of the third part include the gratings formation by the direct scanning of the single fs laser beam and the intereference of the multi fs laser beams respectively, the refractive index changes calculation and analyzation by measuring the diffraction efficiencies, and the investigation on optical nonlinearities of metallic nanoparticles doped glasses by Z-scan and optical limiting measurements. A series of the achieved research results are summarized as follows. By irradiation of a Ti: Sapphire fs pulsed laser and further heat treatment, metallic nanoparticles were space-selectively precipitated inside the metallic ions doped silicate glasses. A possible mechanism for the nanoparticles precipitation is proposed that the metallic ions in the irradiated regions are first reduced to atoms by fs laser through multiphoton absorption process, and then the atoms accumulate and form metallic nanoparticles during the further heat treatment. The influence of laser irradiation and annealing conditions on the precipitation behaviors of metallic nanoparticles was investigated. The sizes of the metallic nanoparticles increase with the increase of the treatment temperature, the average laser power and the irradiation time. The size and spatial distribution can be controlled by the laser irradiation and treatment conditions. The precipitated metallic nanoparticles in the glasses and their colors are stable at room temperature. By using Z-scan technique and optical limiting measurement, the saturabe absorption and optical limiting properties at 532nm wavelength of gold nanoparticles precipitated from gold ion doped glass by above process were evaluated. The nonlinear optical properties of such metallic nanoparticles precipitated glasses changes with the variation of the fs laser irradiation and heat treatment conditions. The precipitation behaviors of the gold nanoparticles induced by different irradiation sources such as X-ray, nanosecond pulsed laser and fs pulsed laser were compared. In the tested silicate glasses, the minimum heat treatment temperature for the precipitation of gold nanoparticles in irradiated area is obviously lower than that in non-irradiated area. The similar tendency is also reflected in the size and distribution of nanoparticles. The metallic nanoparticles can be modified and erased by re-irradiation of fs laser on the metallic nanoparticles formed in the irradiated area. Influence of some additives of the glass composite on the precipitation behavior of metallic nanoparticles was discussed. The experimental results show that, introducing PbO to the gold ions doped glasses resulted in inhibition of hole-trapped centers induced by the fs laser irradiation, and promotion of the formation and growth of the gold nanoparticles. Addition of AI2O3 to Ag+-doped silicate glass resulted in inhibition of color centers generation and an apparent increase of the heat treatment temperature for the precipitation of Ag nanoparticles. Microgratings with several-tens micrometer size were fabricated in gold nanoparticles doped glasses by the intereference process of fs laser beams and subsequent heat treatment. The smallest period achieved of the micrograting and width was ～500nm and ～150nm, respectively. Also, holographic double-microgratings in the gold nanoparticle precipitated area fabricated. Each size in the double-microgratings and distance between the two microgratings could be controlled by the fs laser irradiation conditions. This technique would be widly utilized to fabricate optical switch, micrograting and photonic crystal etc. The diffraction efficiency of the gratings formed by direct scan and interference of fs laser were measured, and corresponding refractive index changes were calculated and analysed. For the grating formed by the fs laser direct scan and subsequent heat treatment inside the glasses, the refractive index change was estimated to be ～lO-4 according to the relation between the diffraction efficiency and refractive index change of phase grating. For the holographic micrograting formed by the interferential fs laser pulses and subsequent heat treatment, the refractive index changes was estimated to be ～10-1. The mechanism of such obvious difference of the refractive index changes between the two kinds of gratings is under investigation. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15356]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 曾惠丹. 飞秒激光空间选择性调控玻璃中金属纳米粒子形成的研究[D]. 中国科学院上海光学精密机械研究所. 2004. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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