Coherent phonon spectroscopy using time-resolved x-ray diffraction

Summary form only given. Time-resolved x-ray diffraction enables one to directly measure the dynamics of solids on atomic length scales in real-time. In this experiment, x-ray diffraction with 2 ps resolution is used to observe coherent acoustic vibrations at frequencies approaching 0.1 THz. The acoustic phonon dispersion relation in InSb near the Brillouin zone center is measured. Microscopic electron-phonon coupling-times are extracted. On time-scales shorter than the dephasing of the coherent oscillations, two-pulse excitation is used to coherently control the amplitude of the vibrational excitations. X-rays from the Advanced Light Source synchrotron are monochromatized to a wavelength of 5 keV and then diffracted off an InSb wafer onto a streak camera detector.