Role of Glass Composition in Waveguide Fabrication with Femtosecond Laser Pulses

紧聚焦飞秒（fs）激光脉冲可以用来改变激光聚焦区域内玻璃的折射率。通过相对于激光聚焦扫描玻璃，可以在玻璃内部制造波导结构。最近已经观察到，在商用磷酸盐玻璃（Schott IOG-1）中用fs激光脉冲制造的波导结构的性质与熔融二氧化硅中的波导结构不同，熔融二氧化硅是迄今为止唯一被广泛研究的玻璃。为了评估光纤激光器制造波导的普遍适用性，本项目深入研究了玻璃成分对光纤激光器制造波导的影响。实验将用于制造和表征各种玻璃中的波导，以确定具有良好波导特性的组合物。与波导形成相关的结构变化将使用光学显微镜以及共聚焦荧光和拉曼光谱进行研究。实验结果将用于详细了解诱导指数变化，结构改性和玻璃热机械性能之间的关系。在此基础上，我们计划建立一个通用模型，根据它们是否适合用激光脉冲制造波导来对玻璃进行分类。利用飞秒（fs）激光脉冲制造光波导作为一种三维全光集成元件的制造技术，在光子学工业以及生物和化学传感器和医疗技术中具有巨大的应用潜力。在不同类型的眼镜上使用这种技术的能力——专门为特定的光子学应用而定制的——对其成功开发至关重要。本计画涉及玻璃成分对激光脉冲制造波导之影响之实验研究。实验结果将用于开发一个模型，从玻璃的物理、结构和热机械性能方面解释玻璃中的波导制造。这个研究项目在本质上是非常多学科的，使用了从材料科学到激光物理到非线性光学的理论概念和实验技术。它通过提供最先进的光学技术的实践经验，为研究生的教育和培训提供了一个独特的机会，这在现在和未来的光电子行业非常重要。

Tightly focused femtosecond (fs) laser pulses can be used to modify the refractive index of glass within the focal region of the laser beam. By scanning the glass with respect to the laser focus waveguide structures can be fabricated inside the glass. It has recently been observed that waveguide structures fabricated with fs laser pulses in a commercial phosphate glass (Schott IOG-1) behave qualitatively different from those in fused silica, the only glass that has been widely studied so far. In order to evaluate the general applicability of waveguide fabrication with fs lasers, this project involves an in-depth study of the effects of glass composition on waveguide fabrication with fs laser pulses. Experiments will be carried out to fabricate and characterize waveguides in a variety of glasses in order to identify compositions with favorable waveguide properties. The structural changes associated with waveguide formation will be investigated using optical microscopy as well as confocal fluorescence and Raman spectroscopy. The experimental results will be used to develop a detailed understanding of the relationship between the induced index changes, the structural modification and the thermo-mechanical properties of the glass. On this basis we plan to develop a general model for categorizing glasses in terms of their suitability for waveguide fabrication with fs laser pulses. The use of femtosecond (fs) laser pulses to fabricate optical waveguides holds tremendous potential as a fabrication technique for three-dimensional all-optical integrated components with applications in the photonics industry as well as in biological and chemical sensors and medical technology. The ability to use this technique with different types of glasses-specifically tailored for a specific photonics application- is critical to its successful exploitation. This project involves an experimental study of the effects of glass composition on waveguide fabrication with fs laser pulses. The experimental results will be used to develop a model that explains waveguide fabrication in glasses in terms of the physical, structural and thermo-mechanical properties of the glass. This research project is very multidisciplinary in nature, using theoretical concepts and experimental techniques ranging from materials science to laser physics to nonlinear optics. It offers a unique opportunity for education and training of graduate students by providing hands-on experience with state-of-the-art optical techniques, which are of great importance within the present and future photonics industry.