title: Acoustic pulse echoes probed with time-resolved X-ray triple-crystal diffractometry.
abstract: Acoustic pulse echoes generated by femtosecond laser irradiation were detected using time-resolved x-ray triple-crystal diffractometry. The determined time-dependent longitudinal strain component for pulse echoes in silicon and gallium arsenide plates showed that the polarity of the strain pulse was dependent on the optically induced initial stress, and that the bipolar pulse waveform was gradually deformed and broadened in the course of propagation. The three-dimensional wave front distortion of pulse echoes was shown simply as the pulse duration broadening, which was consistent with a boundary roughness for an unpolished plate.
authors.affiliation: Interdisciplinary Graduate School of Engineering Sciences, Kyushu Univ., Kasuga, Fukuoka 816-8580, Japan.
authors.forename: Yujiro
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kirimura
authors.forename: Noboru
authors.initials: N
authors.lastname: Tsukuda
authors.forename: Eiichi
authors.initials: E
authors.lastname: Kuramoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ishikawa