Ultrafast and Nanoscale Raman Approaches for Materials Science

Our lab focuses on the development and application of Raman spectroscopies with high temporal and spatial resolution, with the goal of understanding local environmental impacts on chemical reaction dynamics. This talk will focus on the use of these spectroscopic and microscopic approaches in order to understand two coupled light-matter systems: plasmon-molecule interactions and excitonic polariton dynamics. In the quest to understand how plasmonic nanomaterials can serve as photocatalysts, we have developed ultrafast surface-enhanced Raman approaches to understand molecule responses following photoexcitation. This talk will focus on our quantitation of plasmon-to-molecule charge transfer, which enables us to determine the yield and energy of hot carriers relevant for driving chemical reactions. Secondly, we have used femtosecond stimulated Raman spectroscopy and resonance Raman intensity analyses in order to understand the similarly strong coupled light-matter system of excitonic polaritons. Here we map out multiple dimensions of the coupled potential energy landscape to determine how coupling to a photonic cavity can change molecular reaction coordinates. Taken together, these works demonstrate how probing multiple molecular degrees of freedom can lead to new insights into the rational design of coupled systems.