Entangled Photon Imaging and Microscopy for Chemical and Biological Investigations

密歇根大学的古德森教授和他的团队在化学系化学测量和成像项目以及“理解大脑倡议”的支持下，正在开发一种光学技术，在对样品损害最小的情况下提高成像空间分辨率。光学显微镜的使用在过去的十年中有了很大的进步。许多光学显微方法已用于材料和生物成像以及化学传感。虽然这些技术在灵敏度上有很大的希望，但有些技术确实需要高的、有潜在破坏性的光照强度。现在需要的是一种化学成像技术，这种技术可以利用双光子过程的高度聚焦行为，同时将峰值强度保持在较低水平。古德森教授正在开发的成像技术使用一束光，其中光子对的量子态是相连的，即纠缠光子。利用量子纠缠的特性，古德森教授和他的团队用极少量的光子以极高的分辨率探测和成像分子。这项发展起来的技术随后使他们能够研究有趣的生物系统，如阿尔茨海默病患者的组织成像和淀粉样蛋白的形成。来自美国国家科学基金会的这种支持也有助于培养和指导化学、物理和材料科学等领域的各种科学家（研究生和博士后）。有了这笔资金，密歇根大学的古德森教授和他的研究小组正在研究一种通过纠缠双光子吸收（ETPA）显微镜来提高化学灵敏度的新方法。纠缠双光子显微镜的概念提供了一个突破，超越了经典的TPA显微镜，允许10个数量级的激发强度降低，这对生物和材料的应用是非常重要的。该项目的目标是a)证明ETPA显微镜在极低输入通量下的灵敏度限制，b)测试ETPA显微镜在极低输入通量和增强的空间分辨率下探测重要化学过程的能力，以及c)将该方法应用于一个重要的化学系统，说明ETPA显微镜方法的影响。这项工作的广泛影响：a)通过WISE计划为中学生提供夏季光学教育经验，b)为高中生提供更广泛的化学和物理经验，重点是光学，c)为下一代可能对包括光学在内的物理科学有浓厚兴趣的教授开发和扩展研讨会。这项研究的影响还包括为化学和成像界提供了一种新的方法，其中包含了关于方法、材料和理论的重要细节。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry and the Understanding the Brain Initiative, Professor Goodson at the University of Michigan and his group are developing an optical technique to enhance imaging spatial resolution with minimal damage to samples. The use of optical microscopy has greatly progressed over the last decade. Many optical microscopic methods have been used in materials and biological imaging as well as chemical sensing. While these techniques hold great promise in sensitivity, some do require high and potentially damaging light intensities in illumination. What is now needed, is a chemical imaging technique which takes advantage of the highly focused behavior of the two photon process, but at the same time it keeps the peak intensity at low levels. The imaging technique under development by Professor Goodson uses a beam of light where the quantum states of photon pairs are linked, i.e. entangled photons. Utilizing the property of quantum entanglement, Professor Goodson and his group probe and image molecules with extremely high resolution and with a very small number of photons. The developed technique subsequently enables them to study interesting biological systems such as tissue imaging and the formation of amyloids with Alzheimer's patients. This support from the National Science Foundation also helps to train and mentor a diverse group of scientists (graduate students and postdoctoral students) in areas such as chemistry, physics and materials science.With this grant, Professor Goodson at the University of Michigan and his research group are investigating a new approach to chemical sensitivity through entangled two-photon absorption (ETPA) microscopy. The entangled two-photon microscopy concept provides a breakthrough over the classical TPA microscopy allowing 10 orders of magnitude lower excitation intensity which is of immense importance for biological and materials applications. The objectives of the project are to a) demonstrate the limits of sensitivity of the ETPA microscopy at very low input flux, b) test the ETPA microscope's ability to probe important chemical processes at very low input flux and with enhanced spatial resolution, and c) apply the methodology to an important chemical system illustrating the impact of the ETPA microscopy method. The broader impact of the work: a) provides summer educational experience in optics through the WISE program for middle school students, b) provides a broader experience for high school students in chemistry and physics with an emphasis on optics, and c) develops and expands a workshop for the next generation professors who might have a strong interest in the physical sciences including optics. The impact of this investigation also includes providing the chemical and imaging community a new approach with important details regarding the specifics of the methodology, materials, and theory.