Super-Resolution Two-Dimensional Infrared Imaging

在化学部化学测量和成像（CMI）计划的支持下，Arnaldo塞拉诺博士和他在圣母大学的团队正在开发一种技术，在与最快的化学反应相匹配的时间尺度上对分子的动态进行成像，短于皮秒（万亿分之一秒），并且在长度尺度上，允许他们解决单个细胞内的事件。可以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有关高度不均匀的微观环境（如细胞内部）的化学的详细问题。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红外光的所谓“衍射极限”，这是使用传统技术可以成像的最小可能长度尺度。该团队正在研究的一种方法是用微观球体记录图像，这些球体充当微小的放大镜。另一种方法涉及图案化入射光以利用“混叠”，当通过两个尖桩栅栏观看时，相同的效果会导致莫尔图案，以便从测量中提取更详细的信息，从而重建高分辨率图像。这些努力有望最终实现对活细胞内化学异质性的新测量。该项目还包括一项计划，组织一个“中西部超快光谱和成像研究生研讨会”，在那里该地区的研究生可以学习先进的光学方法和与同事的网络。该项目将研究提高宽视场二维红外（2D）显微镜的空间分辨率的方法。红外成像的最新发展，包括宽场2D显微镜，使得在微米尺度上测量材料的超快动力学成为可能。虽然2D显微镜能够实现一种新的无标记成像，但该技术仍处于起步阶段，并且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2kHz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各样的异质系统上进行，例如红外等离子体器件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，以及在高中和本科阶段强调物理科学课程中数学技能的教育推广活动。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

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.