Extended Data Fig. 9: Structural dynamics excited by 400-nm optical pulses.
a, Normalized changes of 004-vortex peak intensity as a function delay. b, Fourier spectra of a. L and T represent the acoustic waves that travel along the out-of-plane direction with longitudinal and transverse sound speeds, respectively. c, Calculated phonon dispersion curves. The vertical dashed line indicates the boundary of the folded Brillouin zones. The shaded region corresponds to the scattering vectors probed in the experiment. The solid circles show the measured modes upon 400-nm excitation, while the stars show the measured modes upon THz excitation. The error bars show the full-width at half-maximum of the peaks in the Fourier spectra. dSL, superlattice periodicity.
