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器可用于在一块玻璃内创建微米大小的结构。这种制造方法为光通信、生物成像、传感和纳米技术等领域的光子器件和电路的制造提供了一个平台。为了充分利用这种超快激光“书写”技术的潜力，设计在器件性能和激光加工性能方面都得到优化的材料是很重要的。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结构。这项研究是加州大学戴维斯分校和密苏里大学的合作项目，为研究生、本科生和大学预科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，并在大学预科阶段开展推广活动。技术细节：飞秒激光在玻璃衬底内写入光波导是一种很有前途的制造集成光子器件的技术。该装置的质量取决于玻璃对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，因为它们允许高浓度稀土离子的掺入，通常在激光暴露区域产生负折射率变化，导致光学性能差。然而，某些组合物表现出器件制造所需的正折射率变化。该项目的总体目标是对控制磷酸盐玻璃对飞秒激光照射响应的材料参数有一个基本的了解。通过实验确定玻璃结构与fs激光加工响应之间的关系，并利用荧光、拉曼、微核磁共振和ESR等技术表征fs激光诱导的玻璃结构变化。利用实验结果建立了描述fs激光响应的相关玻璃结构参数的模型，并最终设计了新的玻璃成分。该项目是光学材料和激光物理（UC-Davis）和玻璃化学（Missouri S&amp；T）专业团队之间的合作，为研究生提供最先进的材料科学和光学技术培训，为本科生提供研究机会，并在大学预科阶段开展推广活动。

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.