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的Keith Nelson博士和北海道大学的Toshirou Tagi博士之间为期三年的合作研究项目。合作者将研究相变附近晶体中的晶格振动，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。对相变和液体-玻璃相变的研究是为了促进我们对凝聚态中结构重排的基本理解。对薄膜的研究可以提供有关薄膜与衬底附着力的重要信息，在微电子和其他行业的薄膜非侵入性表征方面也有直接的应用。由纳尔逊博士领导的美国团队已经开发出皮秒和飞秒的时间域光散射方法，用于研究凝聚态物质中的声学和光学声子。八木博士领导的这个日本团队特别感兴趣的是，使用飞秒时间分辨方法研究了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。合作的互惠互利将是双向技术转让，以显著增强两组的实验能力，就两组感兴趣的相关主题进行智力交流，并就两类重要材料的结构相变进行合作实验结果。***

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. ***