Collaborative Research: Designing Glass Structures for Femtosecond Laser Processing

非技术描述：脉冲短于万亿分之一秒的超快激光可以用来在一块玻璃内制造微米大小的结构。这种制作方法为制作在光通信、生物成像和传感以及纳米技术中应用的光子器件和电路提供了平台。为了充分发挥这种超快激光“写入”技术的潜力，重要的是设计出在器件性能和激光加工行为方面都进行了优化的材料。为了实现这一目标，该项目旨在开发这种材料，并详细了解激光如何在微观尺度上改变材料的结构。这项研究是加州大学戴维斯分校和密苏里州S公司合作进行的，为研究生、本科生和预科学生提供最先进的材料科学和光学技术方面的培训，为本科生提供研究机会，并在大学预科水平上开展外联活动。技术细节：飞秒激光写入玻璃基板内的光波导是制造集成光子器件的一种很有前途的技术。该装置的质量取决于玻璃对飞秒激光加工条件的响应以及玻璃成分。磷酸盐玻璃是有源器件的主体材料，因为它们允许掺入高浓度的稀土离子，通常会在激光曝光区产生负折射率变化，导致光学性能较差。然而，某些组合物表现出正的折射率变化，这是器件制造所希望的。该项目的总体目标是对控制磷酸盐玻璃对飞秒激光照射的响应的材料参数有一个基本的了解。用荧光、拉曼、显微核磁共振和电子自旋共振等技术研究了飞秒激光对玻璃结构的影响，确定了玻璃结构与飞秒激光响应之间的关系。实验结果被用来建立一个模型，根据相关的玻璃结构参数来描述飞秒激光的响应，并最终设计出新的玻璃成分。该项目是在光学材料和激光物理(加州大学戴维斯分校)和玻璃化学(密苏里州S和T；T)专业人士之间的合作，为研究生提供最先进的材料科学和光学技术方面的培训，为本科生提供研究机会，并在大学预科水平上开展外联活动。

NON-TECHNICAL DESCRIPTION: Ultrafast lasers with pulses shorter than a trillionth of a second can be used to create micron-sized structures inside a piece of glass. This fabrication method provides a platform for the fabrication of photonic devices and circuits with applications in optical communications, bio-imaging and -sensing and nanotechnology. In order to exploit the full potential of this ultrafast laser 'writing' technique it is important to design materials that are optimized both in terms of device properties and laser processing behavior. Towards this goal this project aims to develop such materials as well as a detailed understanding of how the laser changes the materials structure on a microscopic scale. The research is a collaboration between UC Davis and Missouri S&T and provides training for graduate, undergraduate and pre-college students in state-of-the-art materials science and optical techniques, research opportunities for undergraduates and outreach activities at the pre-college level. TECHNICAL DETAILS: Femtosecond (fs)-laser writing of optical waveguides inside glass substrates is a promising technique for fabricating integrated photonic devices. The quality of the device is determined by the response of the glass to fs laser processing conditions as well as glass composition. Phosphate glasses, which are of interest as host materials for active devices since they allow incorporation of high concentrations of rare earth ions, typically produce negative refractive index changes in the laser-exposed regions, leading to poor optical performance. However, certain compositions exhibit positive refractive index changes that are desirable for device fabrication. The overall objective of the project is to develop a fundamental understanding of the materials parameters that govern the response of phosphate glass to femtosecond laser irradiation. Experiments are conducted to determine the relationships between glass structure and response to fs-laser processing and to characterize fs-laser induced changes in glass structure using fluorescence, Raman, micro-NMR and ESR techniques, among others. The experimental results are used to develop a model that describes the fs-laser response in terms of relevant glass structural parameters and ultimately design new glass compositions. This project is a collaboration between groups with expertise in optical materials and laser physics (UC-Davis) and glass chemistry (Missouri S&T) and provides training for graduate students in state-of-the-art materials science and optical techniques, research opportunities for undergraduates and outreach activities at the pre-college level.