Generation of acoustic pulses from a photo-acoustic transducer measured by time-resolved x-ray diffraction

摘要

Picosecond acoustic pulses generated by ultrafast optical excitation of a 100nm gold photo-acoustic transducer deposited on a germanium substrate are observed using time-resolved x-ray diffraction. The resulting pump-probe spectra reveal that the spatiotemporal structure of the acoustic pulse is bipolar with acoustic wavevectors up to inverse of the film thickness.