Virtual and CREOL: CROL-103

Title: Time-domain optical control of molecular and material dynamics

Abstract: Since the advent of femtochemistry, researchers have sought to both manipulate and monitor chemical dynamics at the intrinsic length and time scales of atoms, electrons, and the bonds that hold them together. Two-pulse pump-probe approaches have long served as the workhorse of this endeavor, providing a window into dynamics launched by an initial excitation. In this seminar, I will describe our efforts to move beyond passive observation by employing multi-pulse pump-control-probe schemes that guide the microscopic partitioning of energy along distinct dynamical pathways. I will highlight suite of modalities that we have developed through their application to two broad classes of systems: (i) semiconductor materials relevant to solar energy conversion -- including halide perovskites, colloidal nanocrystals, and two-dimensional materials -- where optical probes track the exchange of energy between photons, electrons, and phonons; and (ii) diatomic gas-phase molecules, representing the most fundamental level of photochemistry, where hard X-ray scattering enables real-space and real-time visualization of wavepacket shaping via coherent control. Together, these efforts advance the broader goal of unveiling and ultimately controlling the coupled electronic and structural dynamics that underpin function in condensed phases.

About the Speaker: Tom Hopper is an Assistant Professor at the Department of Chemistry, University of Central Florida. After completing a Masters degree in Chemistry at Newcastle University (2016), he became the first graduate student of Artem Bakulin at Imperial College London, which began with building a brand-new femtosecond laser suite for the Chemistry department, and culminated in numerous awards for his thesis on ultrafast photophysics in organic, hybrid and nanoscale materials and devices. Following an EPSRC Doctoral Prize Fellowship in the same lab, Tom moved to Stanford University (2021) as a TomKat Postdoctoral Fellow in Sustainable Energy, continuing research into energy transport in emerging photovoltaics in the group of Aaron Lindenberg. Tom then joined SLAC National Accelerator Laboratory (2023) full time as a Postdoctoral Scholar in Photon Science. Working with Adi Natan and Kelly Gaffney, Tom developed pulse sequences to exert coherent control of photochemical structural and solvation dynamics, and image these processes with the world's brightest X-rays at the LCLS free electron laser. Since December 2024, Tom has led a research group at UCF, focusing on ultrafast laser control tools to advance the materials & device science of molecular and nanoscale systems for novel energy, optoelectronic and quantum technologies.

Virtual Location URL: https://ucf.zoom.us/j/91734379009?from=addon