U.S.-Japan Cooperative Research: Study of Phase Transition Dynamics by Coherent Phonon Excitation

9418058 Nelson该奖项支持麻省理工学院Keith Nelson博士和北海道大学Toshirou Tagi博士为期三年的合作研究项目。合作者将研究晶体在相变附近的晶格振动，玻璃形成液体和聚合物中的声波，以及聚合物和其他薄膜中的声波。相变和液-玻璃相变的研究旨在促进我们对凝聚态物质结构重排的基本理解。薄膜的研究可以提供关于薄膜与衬底粘附的重要信息，也可以直接应用于微电子和其他工业中薄膜的非侵入性表征。由Nelson博士领导的美国研究小组开发了皮秒和飞秒时域光散射方法，用于研究凝聚态物质中的声子和声子。由Yagi博士领导的日本团队特别感兴趣的是使用飞秒时间分辨方法来研究一类重要晶体的相变，这些晶体的非线性光学特性在实际设备中得到了广泛的利用。合作的共同利益将是双向技术转移，以显著提高两组的实验能力，就两组感兴趣的相关主题进行知识交流，以及在两类重要材料的结构相变方面的合作实验结果。＊＊＊

9418058 Nelson This award supports a three-year cooperative research project between Dr. Keith Nelson of the Massachusetts Institute of Technology and Dr. Toshirou Tagi of Hokkaido University. The collaborators will investigate lattice vibrations in crystals near phase transitions, acoustic waves in glass-forming liquids and polymers, and acoustic waves in polymers and other thin films. The study of phase transitions and liquid-glass transitions is intended to advance our fundamental understanding of structural rearrangements in condensed matter. The study of thin films can provide important information about adhesion of films to substrates, and also has immediate applications to noninvasive characterization of films in microelectronics and other industries. The U.S. group, led by Dr. Nelson, has developed picosecond and femtosecond time-domain light scattering methods for study of acoustic and optic phonons in condensed matter. Of particular interest for the Japanese group, led by Dr. Yagi, is the use of femtosecond time-resolved methods for the study of phase transitions in an important class of crystals whose nonlinear optical properties are widely exploited in practical devices. The mutual benefits of the collaboration will be two-way technology transfer for the significant enhancement of both groups experimental capabilities, intellectual exchange concerning the related topics of interest to both groups, and collaborative experimental results on structural phase transitions in two important classes of materials. ***