Sound Velocities at High Pressure: An Application of Laser Induced Phonon Spectroscopy

PI将在大学建立一个实验室， 华盛顿，用于测量 高温高压下的地幔矿物。 对 在成功的初步实验的基础上，他 这表明，这是可行的，使这样的测量对 小（100 μ m）样品在金刚石砧高压室中。 激光形式的脉冲受激散射（ISS） 诱导声子光谱学提供了一种稳健的技术， 研究晶体在高压下的弹性。 相干声子，由一对重叠激光产生 脉冲在时间和空间上调制折射率 的样本。 探测激光脉冲可以被 产生的时间相关光栅。 信号是命令 比任何其他技术都要大。 这种技术 也回避了不确定的折射率问题， 与布里渊散射实验有关。 的 确定地幔条件下的压力和 候选地幔弹性常数的温度导数 矿物成分是当前矿物学研究的重要课题之一 物理学

The PI will assemble a laboratory at the University of Washington for the purpose of measuring sound velocities of candidate mantle minerals at high pressure and temperature. On the basis of successful preliminary experiments, he has demonstrated that it is feasible to make such measurements on small (100 um) samples in a diamond anvil high pressure cell. Impulsive stimulated scattering (ISS) in the form of laser induced phonon spectroscopy provides a robust technique to investigate the elastic properties of crystals at high pressure. Coherent phonons, generated by a pair of overlapping laser pulses, temporally and spatially modulate the index of refraction of sample. A probe laser pulse can be strongly diffracted by the resultant time-dependent grating. Signals are orders of magnitude greater than with any other technique. This technique also side-steps the uncertain index-of-refraction problem often associated with Brillouin scattering experiments. The determination, under mantle conditions, of pressure and temperature derivatives of elastic constants for candidate mantle constituents is one of the important current problems in mineral physics.