Abstract by Megan Nielson
Chemistry and Biochemistry
Analysis of Terahertz Phonon Modes in beta-Barium Borate
Terahertz (THz) radiation can excite specific, frequency-dependent, vibrations in crystals and sufficiently strong radiation can drive those vibrations nonlinearly. Previous work in the Johnson Lab showed that different nonlinear responses (such as two-photon absorption and anharmonic phonon coupling) can be differentiated via 2D spectroscopy. We are currently studying beta-barium borate (BBO) using THz pump-probe measurements to analyze the nonlinear response, better understand ultrafast energy flow, and characterize the nonlinear energy flow as phononic or photonic.