OP: Model Theory of Single Nanoparticle Photothermal Absorption Spectroscopy via Optical Microresonators

华盛顿大学的David J. Masiello获得了化学系化学理论、模型和计算方法项目的奖励，他开发了理论和实验方法来理解和解释一类新的单粒子光热吸收光谱实验。光热光谱为测量室温下单分子的吸收光谱提供了一个独特的平台，在生物学、材料科学等领域有许多潜在的应用。Masiello和他由本科生、研究生和博士后组成的多元化团队正在努力了解单个纳米级物体（如单分子、量子点和等离子体纳米粒子）是如何处理光的。光可能被粒子吸收，也可能被散射。虽然很难测量，但吸收包含了关于纳米粒子的重要信息，而这些信息不存在于散射中。Masiello的理论进步，应用到这些新的最先进的吸收实验中，使实验人员能够在单个粒子水平上区分吸收和散射。他们还确定了其他迷人现象所需的条件，如实验中使用的高质量微谐振腔中远距离纳米级物体之间的远距离非辐射能量转移和室温量子纠缠。Masiello和一位同事开发并教授了一门研究生水平的科学写作课程，旨在培养和提高不同学生群体的科学交流技能。本工作的技术重点是：1)建立分子、量子点和金属纳米结构中单个和集体电子激发的简单而严格的分析模型，以及它们与支撑环形微谐振腔的高质量光学低语廊模式的相互作用；2)利用这些模型和麦克斯韦方程组的全波数值模拟来理解光热吸收光谱中存在的复杂线形；3)研究光学微谐振器在远距离纳米级物体之间的相互作用和相干能量转移的能力，这些物体在超远程类里德堡等离子体中混合甚至纠缠。

David J. Masiello of the University of Washington is supported by an award from the Chemical Theory, Models and Computational Methods Program in the Division of Chemistry to develop theoretical and experimental approaches to understand and interpret a new class of single particle photothermal absorption spectroscopy experiments. Photothermal spectroscopy offers a unique platform to measure absorption spectra of single molecules at room temperature and has many potential applications in biology, materials science and other fields. Masiello and his diverse team of undergraduates, graduate students and postdoctoral associates are working to understand how individual nanoscale objects such as single molecules, quantum dots, and plasmonic nanoparticles process light. The light may be absorbed into the particle or it may be scattered. While it is difficult to measure, absorption contains important information about the nano-particle that is not present in the scattering. Masiello's theoretical advances, applied to these new state-of-the-art absorption experiments, allow the experimentalists to distinguish absorption from scattering at the single particle level. They also determine the conditions that are required for other fascinating phenomena such as long-range, nonradiative energy transfer and room-temperature quantum entanglement between distant nanoscale objects in the high quality microresonator cavities that are used in the experiments. Masiello and a colleague have developed and teach a graduate level course on scientific writing aimed at developing and enhancing the scientific communication skills for a diverse group of students.The technical focus of this work is to: 1) develop simple yet rigorous analytical models of the individual and collective electronic excitations in molecules, quantum dots, and metallic nanostructures as well as their interaction with the high-quality optical whispering-gallery modes of their supporting toroidal microresonator cavity; 2) use these models together with full-wave numerical simulations of Maxwell's equations to understand the complex line shapes present in photothermal absorption spectra; and 3) investigate the ability of optical microresonators to assist in the interaction and coherent energy transfer between distant nanoscale objects hybridized or even entangled in ultra-long-range Rydberg-like plasmons.