Rapid chemical imaging with sum-frequency generation microscopy

在这个由化学部化学测量和成像计划资助的项目中，加州大学欧文分校的Eric Potma教授正在开发一种快速激光扫描非线性光学（NLO）显微镜平台，其中包括一种新的化学选择性成像模式：和频生成（SFG）。这一进展为活跃在生物学和材料研究领域的研究人员提供了一种新形式的化学成像对比度，这种对比度以前在实际的采集速度和分辨率下是不可用的。将SFG模态添加到光学显微镜上依赖于新的消色差光学元件，这些元件是在该项目中特别设计和开发的，并且可能在其他形式的红外成像和显微镜中找到重要的新应用。 这项工作的更广泛的影响包括使用SFG成像平台作为生物物理学研究生课程的培训工具，以及开发面向社区的互动步行图尔斯之旅，通过当地的荒地，照亮自然界中的生物物理效应。SFG使得可视化一类特殊的材料成为可能，即那些在分子水平上表现出非中心对称性的材料。由于SFG对分子振动也很敏感，因此所得图像可以根据化学键振动区分非中心对称材料。作为一种成像方式，这种对比机制使研究人员能够以迄今为止仍然无法达到的图像采集速度对无数材料进行详细研究，包括生物纤维和手性微晶。

In this project funded by the Chemical Measurement and Imaging program of the Chemistry Division, Professor Eric Potma of the University of California, Irvine, is developing a fast laser-scanning nonlinear optical (NLO) microscope platform that includes a new chemically selective imaging modality: sum-frequency generation (SFG). This advance offers researchers active in the fields of biology and materials research a new form of chemical imaging contrast, which was previously not available at practical acquisition speeds and resolution. The addition of the SFG modality onto the optical microscope relies on new achromatic optical components, which are especially designed and developed in this project, and which may find important new applications in other forms of infrared imaging and microscopy. Further broader impacts of this work include the use of the SFG imaging platform as a training tool in a biophysics graduate course and the development of community-oriented, interactive walking tours through local wildlands that illuminate biophysical effects in nature.This project integrates the unique imaging capabilities of SFG into a laser-scanning optical microscope. SFG makes it possible to visualize a special class of materials, namely those that exhibit non-centrosymmetry on a molecular level. Because SFG is also sensitive to molecular vibrations, the resulting images can differentiate non-centrosymmetric materials based on their chemical bond vibrations. As an imaging modality, this contrast mechanism enables researchers to perform detailed studies on a myriad of materials, including biological fibers and chiral microcrystals, at image acquisition speeds that have hitherto remained out of reach.