title: Phonon dynamics in γ-ray irradiated sapphire crystals studied by fs-CARS technique.
abstract: We have studied the ultrafast dynamics of coherent phonons in sapphire crystals irradiated with 60Co γ-rays for three different doses by femtosecond time-resolved coherent anti-Stokes Raman scattering (fs-CARS) technique at room temperature. The obtained fs-CARS signals exhibit well-defined quantum beats, which are ascribed to the interference of the 645 and 750 cm-1 phonon modes. The dephasing times of the two modes both decrease with increasing irradiation dose, which is due to the scattering of coherent phonons by the defects introduced by γ-ray irradiation.
authors.affiliation: Department of Physics, Center for Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Du
authors.forename: Mingfu
authors.initials: M
authors.lastname: Zhang
authors.forename: Qingkun
authors.initials: Q
authors.lastname: Meng
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Song
authors.forename: Xing
authors.initials: X
authors.lastname: He
authors.forename: Yanqiang
authors.initials: Y
authors.lastname: Yang
authors.forename: Jiecai
authors.initials: J
authors.lastname: Han