玻璃空间选择性分相控制和三维连通多孔结构构建及功能化

Construction of novel sensing unit with elevated sensitivity, superior reliability and high integration density is of great technological importance for optical sensors. The porous structures with porosity on the micro/nanometer scale and high specific surface are attractive for improving interactions between sensing unit and analyte. While many of these structures can be realized through traditional methods such as electrochemically etching and electron beam lithography, there remains great challenge in space-selective fabrication of porous structure inside bulk materials. In this project, we will propose a strategy which enables spatial construction of three-dimensional porous structures by using direct femtosecond laser writing inside glass materials. The systematic method for continuously tuning the pore size and specific surface will be established. Based on the elaborate researches of design and fabrication of porous channels with analyte separation function, infiltration of functional species with resonance amplification property and creation of high-quality waveguides crossing the porous channels, the novel three-dimensional optical sensors suitable for optically addressing and gifted remarkable advantages such as highly compact, elevated sensitivity and superior reliability will be constructured. In addition, the work based on this project will be very helpful for a better scientific understanding of laser-matter interaction and upgrading traditional glass materials.

光学传感器的核心部件即敏感单元对传感器的灵敏度、集成度和可靠性起了决定性作用。多孔结构由于其具有适合化学/生物分子吸附的大比表面积是用于构造高灵敏度和高集成度传感单元的理想介质，但传统多孔结构不适合进行三维微加工的缺点限制了其作为高性能光传感器敏感单元的应用。本项目拟开展飞秒激光-分相玻璃相互作用和新型光传感单元开发的研究：通过飞秒激光在玻璃内部空间选择性诱导分相的控制，构造三维多孔微通道，建立玻璃内部孔径与比表面积连续可调的三维连通多孔通道的激光加工制备原理与方法；通过基于微孔的表面/界面修饰（如具有传感共振放大效应的功能结构担载）、具有分离功能的微孔及低损耗波导结构设计与构造，开发具有高灵敏特性的掩埋型光传感敏感单元。基于该项目开展的利用飞秒激光实现玻璃材料微观结构调控的基础研究对于理解飞秒激光与玻璃材料相互作用、改造传统玻璃材料并实现新功能化具有十分重要的意义。

本课题采用分子动力学方法和HAAD-STEM对多组分玻璃的微结构进行理论模拟和实验表征，确定了玻璃中本征的非均匀结构是玻璃结晶和分相的起始点；从横截面和纵截面光场分布角度研究了飞秒激光引起分相的物理机制，发现飞秒激光引起的玻璃结构转变和离子迁移与局部分相密切相关，并在Na2O-SiO2玻璃体系中实现了空间选择性诱导分相；利用飞秒激光直写技术通过在玻璃内部进行超快、空间选择性分相控制，结合后续热处理和定向腐蚀，构造了三维多孔微通道，并确定了孔径与比表面积连续可调的关键工艺，演示制备长度可达2厘米的连通多孔长程微通道；通过微孔设计与构造，具有传感共振放大效应的Ag纳米颗粒的担载调控，开发了基于高灵敏度、多功能和高集成度敏感单元的光学传感器，拉曼信号强度是常用的Ag纳米颗粒基传感单元的7倍。在包括ACS Nano、Adv. Opt. Mater.、Opt. Lett.等期刊共发表SCI论文15篇，申请发明专利14项，项目负责人获得国际玻璃协会Gottardi奖等奖项。