Super-Resolution Two-Dimensional Infrared Imaging

在化学系化学测量和成像(CMI)项目的支持下，圣母大学的Arnaldo Serrano博士和他的团队正在开发一种技术，以匹配最快的化学反应，短于皮秒(万亿分之一秒)的时间尺度上成像分子的动力学，并在长度尺度上使它们能够解析单个细胞内的事件。能够同时提供高时间分辨率和高空间分辨率的化学信息的成像方法可以帮助回答关于高度不均匀的微观环境的化学的详细问题，例如细胞内部。为了使这种测量成为可能，研究小组正在研究几种方法来克服所谓的红外光“衍射限制”，这是使用传统技术可以成像的最小长度尺度。该团队正在寻求的一种方法是使用充当微型放大镜的微球体来记录图像。另一种方法涉及对入射光进行图案化，以利用“混叠”，这与通过两个桩栅栏查看时产生莫尔图案的效果相同，以便从测量中提取更详细的信息，以便重建高分辨率图像。这些努力有望最终实现对活细胞内化学异质性的新测量。该项目还包括一项组织“中西部超快光谱和成像研究生研讨会”的计划，该地区的研究生可以在那里学习先进的光学方法和与同事建立网络。该项目将研究提高广域二维红外(2DIR)显微镜空间分辨率的方法。红外成像的最新发展，包括广视场二维红外显微镜，使在微米尺度上测量材料的超快动力学成为可能。虽然二维红外显微镜能够实现一种新的无标记成像，但这项技术仍处于初级阶段，仍然受到红外光学的低空间分辨率(约3微米)的限制。该项目利用2DIR信号的固有非线性，使用微球近场增强和结构照明显微镜(SIM)在纳米范围内进行超快振动测量。这种分辨率的增强将使超快红外成像能够在各种不同的系统上进行，例如红外等离子体设备和生物样品的亚细胞结构。这项工作的更广泛的影响包括为研究生和本科生提供高级培训机会，以及在高中和本科生的物理课程中强调数学技能的教育推广活动。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 (CMI) Program in the Division of Chemistry, Dr. Arnaldo Serrano and his group at the University of Notre Dame are developing a technique to image the dynamics of molecules on a time scale that matches the fastest chemical reactions, shorter than a picosecond (one trillionth of a second), and on a length scale that allows them to resolve events inside of a single cell. Imaging methods that can provide chemical information with both high time resolution and high spatial resolution can help answer detailed questions about the chemistry of highly nonuniform microscopic environments, such as the interior of a cell. To make such measurements possible, the research team is investigating several approaches to overcome the so-called “diffraction-limit” for infrared light, which is the smallest possible length scale that can be imaged using traditional techniques. One approach the team is pursuing involves recording images with microscopic spheres that act as tiny magnifying glasses. Another approach involves patterning the incoming light to take advantage of “aliasing”, the same effect the causes moiré patterns when looking through two picket fences, in order to extract more detailed information from a measurement in order to reconstruct high-resolution images. These efforts hold promise for eventually enabling new measurements of the chemical heterogeneity inside living cells. The project also includes a plan to organize a “Midwest Ultrafast Spectroscopy and Imaging Graduate Workshop”, where graduate students in the region can learn about advanced optical methods and network with colleagues.This project will investigate methods for enhancing the spatial resolution of wide-field two-dimensional infrared (2DIR) microscopy. Recent developments in infrared imaging, including wide-field 2DIR microscopy, make it possible to measure the ultrafast dynamics of materials on the micron-scale. While 2DIR microscopy enables a new kind of label-free imaging, the technique is still in its infancy and remains limited by the low spatial resolution (about 3 microns) of infrared optics. This project takes advantage of the intrinsic nonlinearity of 2DIR signals to make ultrafast vibrational measurements in the nanometer regime using microsphere-enabled near-field enhancements and structured illumination microscopy (SIM). Such enhancements of the resolution would enable ultrafast IR imaging on a wide variety of heterogenous systems, such as infrared plasmonic devices and the subcellular structures of biological samples. The broader impacts of the work include advanced training opportunities for graduate and undergraduate research students, and educational outreach activities emphasizing mathematics skills in physical science courses at the high school and undergraduate levels.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.