Multimodal Nonlinear Optical Characterization of Biomaterials

这一研究计划旨在开发基于非线性光学过程的新的和改进的显微镜和光谱分析工具，当它们整合到一个内聚显微镜平台时，将被用于发现广泛和非传统材料系统的新结构和特性，包括浓缩生物分子组件和地质材料。一种使用强激光脉冲的特殊成像类型被称为非线性光学显微镜，这个不断扩展的框架包括双光子激发荧光、二次谐波产生、三次谐波产生、四波混频和相干反斯托克斯拉曼散射等技术。尽管它适用于成像和表征广泛的材料系统，但目前这项技术作为一种“生物医学成像”工具是完全站稳脚跟的。建立我的研究计划的一个主要方法是调查和展示这个强大的工具在回答其他学科中重要问题的潜力，如生物材料、软凝聚物质、地球科学和古生物学。为了实现这一目标，我们将建造一种简化但尖端的基于超快(低于70飞秒)激光的扫描显微镜，同时集成多种线性和非线性光学成像模式。特别是，最近的进展已经允许利用单个超快激光源实现基于受激拉曼过程的无标记和化学特定的对比机制。一种这样的方法需要用专门的微结构光纤和高色散玻璃随后产生和整形宽带光，从而消除了对分离(和昂贵的)多个皮秒激光光源的需要。建立这些能力需要在超快激光光子学、非线性光学、显微镜、仪器和电子学方面的大量专业知识，因此将是培训各级教育中高素质学生和研究人员的绝佳场所。

This research program seeks to develop new and improved microscopy and spectroscopy tools that are based on nonlinear optical processes, and which, when integrated in concert into a cohesive microscopy platform, will be brought to bear on discovering new structures and properties of a wide and non-traditional range of materials systems, including condensed biomolecular assemblies and geological materials. An particular type of imaging that uses intense laser pulses is known as nonlinear optical microscopy, and this ever-expanding framework includes such techniques as two-photon excitation fluorescence, second-harmonic generation, third-harmonic generation, four-wave-mixing, and coherent anti-Stokes Raman scattering. Despite its applicability to imaging and characterizing a wide range of materials systems, at present this technology is fully entrenched as a "biomedical imaging" tool. A main approach in establishing my research program is to investigate and demonstrate the potential of this powerful tool to answer important questions in other disciplines such as biomaterials, soft-condensed matter, the geosciences, and paleobiology. To accomplish this goal, we will build a simplified but cutting-edge ultrafast (sub-70 femtosecond) laser-based scanning microscope that simultaneously integrates numerous linear and nonlinear optical imaging modalities. In particular, recent advances have allowed for the implementation of label-free and chemically-specific contrast mechanisms based on stimulated Raman processes utilizing a single ultrafast laser source. One such approach requires the subsequent generation and shaping of broadband light with specialized micro-structured optical fibres and high-dispersion glass, thus obviating the need for separate (and expensive) multiple picosecond laser sources. Establishing these capabilities requires considerable expertise in ultrafast laser photonics, nonlinear optics, microscopy, instrumentation, and electronics, and will thus represent an excellent venue for the training of highly qualified students and researchers at all levels of education.