Colloquium: Vanessa Huxter

    Thursday, October 31, 2013 - 3:30pm - 5:00pm
    Meinel 307

    "From Diamond Defects to Clever Plants: Mapping Energy Flow with Ultrafast Optical Spectroscopy"


    Ultrafast electronic spectroscopy connects the spatial, temporal and dynamic landscapes of complex systems. These connections are essential to our understanding of structure-function relationships and energy transport. Using two-dimensional electronic spectroscopy, or 2DES, we can map the flow of energy through a system by correlating the initial absorptive interaction with the signal emission. By generating correlation maps, 2DES allows us to observe the evolution of vibrational and electronic coherences and populations, providing unprecedented insights into couplings and energy transfer. Using 2DES to study synthetic and natural photosynthetic pigment systems provides insight into the advantages of particular molecular architectures that are ubiquitous in nature, demonstrating the importance of static disorder and vibrational coupling. The critical role of vibrations in these pigments is mirrored in the response of the nitrogen vacancy centers in diamond (NV-diamond) quantum material system. 2DES studies of NV-diamond reveal an array of coherent nuclear vibrations coupled to the electronic state, providing the first glimpse of its ultrafast dynamics [1]. In this system, strongly coupled local modes, primarily associated with nuclear motion localized to within a couple of unit cells of the defect, dominate the vibrational bath. These initial ultrafast dynamics provide a starting point for new insights into dephasing, spin addressing and relaxation — processes key to quantum computing and sensing applications. In addition to 2DES, I will discuss a frequency generation ultrafast spectroscopic technique that reveals relationships between delocalized excitations, providing a novel and generalizable means to understand relaxation in strongly coupled systems.

    [1] V. Huxter et al., Nature Physics (2013) Advance Online Publication (doi:10.1038/nphys2753)

    Speaker Bio(s): 

    Vanessa Huxter joined the faculty at the University of Arizona in August 2013 as an assistant professor in the Department of Chemistry and Biochemistry. She received her B.Sc. from McGill University (Canada) and her Ph.D. from the University of Toronto (Canada) and went on to hold an Natural Sciences and Engineering Research Council of Canada Postdoctoral Fellowship jointly at the University of California, Berkeley, and Lawrence Berkeley National Laboratory.

    She has authored papers and book chapters on topics ranging from semiconductor spin dynamics to correlation in molecules and vibrational coherences in solid-state materials. Her current research interests span ultrafast spectroscopy and microscopy and are focused on developing new techniques to understand energy dynamics in synthetic and natural light harvesting systems, nanoscale organization and quantum materials.