3 research outputs found
Pump Pulse Bandwidth-Activated Nonlinear Phononic Coupling in CdWO
To control structure-function relationships in solids with light, we must
harness the shape of the potential energy surface, as expressed in anharmonic
coupling coefficients. We use two-dimensional terahertz (THz) spectroscopy to
identify trilinear coupling between sets of vibrational modes in CdWO. It
is generally understood that efficient trilinear coupling occurs when the
frequencies of two coupled modes add or subtract to the frequency of the third
mode. Interestingly, we observe that this condition is not necessary: the THz
driving-pulse itself can activate the coupling by contributing broad frequency
content to the initial motion of the excited modes. Understanding that the
bandwidth of the driving force can activate energy-flow pathways has broad
implications for coherent control of collective modes using intense THz light
pulses.Comment: 27 Pages, 15 Figure