Polariton Dynamics - Dr. Jeff Owrutsky

I will describe recent work that involves coupled excitation to produce polaritons. Polaritons are quasiparticles of mixed optical-material nature that provide an opportunity for designing new properties in material systems. Our group works on steady state and time-resolved optical studies of molecules and materials to follow processes such as photochemistry and energy transfer. The first coupled system is vibration cavity polaritons, in which the optical mode of cavity and molecular vibrational absorption mix to produce new states called polaritons. Our interest in cavity polaritons is sparked by recent reports that they can modify chemical reactions on the fly. Our group has been investigating whether cavities alter transient, relaxation properties of molecular vibrations that might explain the modified chemistry. The second type of coupling is active tuning of phonon polaritons. Surface phonon polaritons (SPhPs) are narrow absorption bands produced in nanostructures of polar dielectrics like silicon carbide.  These resonances resemble plasmon bands but are narrower and more naturally in the infrared region. SPhPs can be tuned by injecting carriers via ultraviolet, which has potential applications for chemical sensing and other nanophotonic and optical processes. Other experimental studies being conducted in our group will also be described, including optical studies of fuel cells and batteries as well as degradation of perfluorinated substances (PFAS) by solvated electrons.