We report on the optical generation and detection of ultrashort acoustic pulses that propagate in three-dimensional semiconductor crystals. Photoexcitaiton of lattice-matched GaP layers grown on Si(001) gives rise to a sharp spike in transient reflectivity due to the acoustic pulse generated at the GaP/Si interface and detected at the GaP surface and vice versa. The extremely short width of the reflectivity spike, 0.5 ps, would translate to a spatial extent of 3 nm or 10 atomic bilayers, which is comparable with the width of the intermixing layer at the GaP/Si interface. The reflectivity signals are also modified by quasi-periodic Brillouin oscillations of GaP and Si arising from the acoustic pulses during the propagation in the crystals. The present results demonstrate the potential application of the simple optical pump-probe scheme in the nondestructive evaluation of the buried semiconductor interface quality.
Switching picosecond magnetoacoustic regimes in a ferromagnetic waveguide
Ioffe Institute（约费研究所）；Institute for Physics of Microstructures, RAS（俄罗斯科学院微观物理研究所）；Lobachevsky State University of Nizhny Novgorod（下诺夫哥罗德罗巴切夫斯基国立大学）；Radboud University（拉德堡德大学）
Probing of magnetic dimensional crossover in CrSiTe$_{3}$ through picosecond strain pulses
Indian Institute of Science Education and research, Kolkata（印度科学教育研究所加尔各答分校）；Tata Institute of Fundamental research, Mumbai（塔塔基础研究所孟买）；S. N. Bose National Centre for Basic Sciences, Kolkata（S.N. 玻色基础科学国家中心加尔各答）
Thermal Characterization of Buried Interfaces in Multilayer Heterostructures via TDTR with Periodic Waveform Analysis
School of Energy and Power Engineering, Huazhong University of Science and Technology（华中科技大学能源与动力工程学院）；School of Mechanics and Engineering Science, Peking University（北京大学力学与工程科学学院）
Time-domain Brillouin scattering theory for probe light and acoustic beams propagating at an angle and acousto-optic interaction at material interfaces
Revealing sub-μm inhomogeneities and μm-scale texture in H2O ice at Megabar pressures via sound velocity measurements by time-domain Brillouin scattering
Unraveling energy flow mechanisms in semiconductors by ultrafast spectroscopy: Germanium as a case study
University of Basel（巴塞尔大学）；University of Cagliari（卡利亚里大学）；Ecole Polytechnique（巴黎综合理工学院）；Institut Polytechnique de Paris（巴黎理工学院）；CEA/DRF/IRAMIS（法国原子能和替代能源委员会/研究与发展部/放射同位素和物质研究所）
