Theme: Photons in Applied Materials
Example Project: Ultrafast laser spectroscopy of electronic materials
Faculty Mentor: Susan L. Dexheimer
Femtosecond laser spectroscopic techniques (1 fs = 10-15 s, or a millionth of a billionth of a second) allow us to study ultrafast physical phenomena. Since femtosecond laser pulses are short compared to the time scales of atomic-scale motions in molecules and solids and of carrier processes in electronic materials, femtosecond techniques can directly time-resolve these processes. Applications of these methods in the Dexheimer laboratory have included fundamental studies of quasiparticle dynamics in molecular-based electronic materials and studies of photo-carrier processes that have a direct impact on the efficiency of solar cell materials. Current NSF-funded work includes studies of exciton and polaron dynamics in structurally tunable charge density wave materials, focusing on the relationship between the nature of the electron-phonon interactions and the formation and evolution of localized electronic excitations. REU students, working with graduate students and the faculty mentor, will investigate branching between exciton and polaron formation, a process that is crucial to understand for the development and optimization of molecular electronic materials. Students will have the opportunity to receive training in optical instrumentation and techniques, signal processing electronics, computer interfacing and data acquisition, data reduction and numerical analysis techniques, and research methodology in the course of their research activities.
Prof. Dexheimer has a long record of mentoring undergraduate researchers, including students from groups traditionally underrepresented in STEM fields, and has provided students with research opportunities that have contributed to their interest in pursuing scientific careers and have enhanced their applications for graduate school admission. Most recently, she has mentored Elizabeth Wells, a promising sophomore physics major who is carrying out modeling of photoexcitation dynamics in charge density wave materials, and Sarah Kim, who carried out modeling of X-ray spectroscopy of these materials  as an undergraduate in bioengineering, and who received an award for this work in a university-wide competition. Prof. Dexheimer was awarded the WSU College of Arts and Sciences Thomas E. Lutz Teaching Award (one awarded annually) in 2015, in recognition of her work in integration of research and education and her work in increasing participation of underrepresented groups, including her work in the WSU Physics and Astronomy Department, the WSU NSF ADVANCE program, and her contributions to the APS Conference for Undergraduate Women in Physics.
 EXAFS Spectroscopy of Fractional Mixed-Valence Charge Density Wave Systems, N.A. Turner, S. S. Kim, J.A. Brozik, M.A. Marcus, S.C. Fakra, and S.L. Dexheimer, J. Phys. Chem. C 123, 6182-6189 (2019)