CAREER: Development of Super-Resolution Scanning Probe Stimulated Raman Microscopy with Excellent Spatial Resolution

在化学系化学测量与成像项目的支持下，利哈伊大学的徐晓吉教授正在开发新的测量方法，探索光如何在纳米级(小于人类头发直径的1000倍)与物质相互作用。拉曼光谱和显微镜是测量分子性质的流行工具，因为它们使研究发现和化学表征对工业、医疗保健和环境监测具有价值。徐教授正在提高受激拉曼显微镜的空间分辨率，以便能够在常规基础上以高度坚固和可靠的方式对尺寸接近大分子的物体进行化学表征。具体地说，该项目检查大气中可能含有有害物质的气溶胶，这些物质可能会导致呼吸道疾病、心力衰竭甚至产前缺陷，从而损害个人的健康。了解气溶胶的组成、来源和转化对于减少其产生或减轻其影响至关重要。除了研究气雾剂，徐博士的团队还在开发一个教育模块，通过身临其境的虚拟现实体验，将尖端科研实验室与标准课堂环境中的中小学生连接起来。通过虚拟现实流媒体向小学生和高中生演示一系列化学反应，从而促进他们对科学的好奇心。此外，徐教授的教育活动正在提高科学外展的有效性，向公众推广科学。能够在小长度尺度上可视化物质的化学性质是拉曼显微镜面临的主要挑战。该项目正在通过将扫描探针显微镜和相干受激拉曼事件相结合来满足对超分辨率拉曼显微镜的需求。受激拉曼过程提供了化学灵敏度。高空间分辨率是通过使用扫描探针显微镜尖端进行纳米级探测来实现的。该项目旨在实现强大而可靠的拉曼成像，以便区分相隔大约10纳米的物体。通过整合徐氏集团发明的纳米级红外成像技术，化学、生物和环境样品的多模式光谱和机械显微镜成为可能。徐教授的团队研究大气中单个亚微米级城市污染物颗粒的化学成分和物理性质，使他的团队能够破译它们的化学来源和光化学转化，识别和控制气溶胶污染是他的团队的最终目标。通过与教育计划相关的努力，小学和高中课堂上的许多学生通过实时多媒体捕获和流媒体设备连接到实验室中的高级研究仪器。学生体验先进研究仪器的操作，巩固学习成果。教育活动将与宾夕法尼亚州伯利恒学区的学生分享。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Xiaoji Xu of Lehigh University is developing new measurement methods that probe how light interacts with matter at the nanoscale (1000 times smaller than the diameter of a human hair). Raman spectroscopy and microscopy are popular tools for measuring properties of molecules as they enable research discoveries and chemical characterizations of value to industry, health care, and environmental monitoring. Professor Xu is improving the spatial resolution of stimulated Raman microscopy so that objects with dimensions approaching those of large molecules can be chemically characterized on a routine basis, and in a highly robust and reliable fashion. Specifically, this project examines aerosols in the atmosphere that may contain harmful substances that can impair the health of individuals by causing respiratory illness, heart failure, or even prenatal defects. Understanding the composition, origin, and transformation of aerosols is of vital importance for reducing their production or lessening their affects. In addition to studying aerosols, Dr. Xu's team is also developing an educational module that connects cutting-edge scientific research laboratories with elementary and high school students in a standard classroom setting, via immersive virtual reality experiences. A range of chemical reactions are demonstrated to elementary and high school students through virtual reality streaming, thereby promoting their curiosity for science. Furthermore, Professor Xu's educational activities are improving the effectiveness of scientific outreach for promoting science to the general public. Being able to visualize the chemical properties of matter on small length scales is a major challenge for Raman microscopy. The project is addressing this need for super-resolution Raman microscopy by combining scanning probe microscopy and coherent stimulated Raman events. Chemical sensitivity is provided by the stimulated Raman process. High spatial resolution is achieved by nanoscale probing using a scanning probe microscope tip. The project aims to achieve robust and reliable Raman imaging so as to differentiate objects separated by roughly 10 nanometers. Through integration of nanoscale infrared imaging techniques invented by the Xu group, multimodal spectroscopic and mechanical microscopy are possible for chemical, biological, and environmental samples. Professor Xu's team studies the chemical composition and physical properties of individual sub-micron-sized urban contaminant particles in the atmosphere, allowing his team to decipher their chemical origins and photochemical transformations, with identification of and control over aerosol pollutions being his team's ultimate goal. From efforts associated with the educational plan, many students in elementary and high school classrooms are connected to an advanced research instrument in a laboratory via real-time multimedia capture and streaming devices. The students experience the operation of advanced research instruments, solidifying learning outcomes. Educational activities will be shared with students in schools in the Bethlehem, PA School District.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.