Laser Induced Kerr effect spectroscopy

激光诱导克尔效应光谱

基本信息

批准号：
09450035
负责人：
SAKAI Keiji
金额：
$ 8.32万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

Complex fluids such as gels, emulsions and bio-systems attract a great physical interest since they could be applied for various industries as new functional materials. The characteristic properties of the complex fluids can be attributed to their large degree of freedom, such as molecular conformation and association. The molecular orientation is one of the important orders, which plays a significant role in creating the liquid crystal phase. The purpose of the study is to develop a new experimental system for observing the orientational molecular dynamics of liquid materials in a wide frequency range.We successfully developed the optical Kerr effect spectroscopy technique with a continuous wave laser. The anisotropic shape of the molecule necessarily accompanies the anistropic dielectricity. The electric field of the polarized laser beam induces the molecular orientation, which is measured by the optical ellipsometry as the Kerr effect. The critical phenomenon was observed for the nematogen near the nematic-isotropic phase transition temperature. The system was improved to observe the dynamic process of molecule rotation. The Pockels cell was driven with a wide band power supply for the high frequency control of the laser polarization. The complex response function was accurately measured, which gives us an important information on the phase transition and the molecular dynamics of liquid crystals. We observed the relaxation of the optical Kerr effect for the first time in the frequency domain in various kinds of liquid crystals. The laser induced molecular orientation technique would be a powerful tool for the investigation of the mechanism of phase transition of liquid crystals.

凝胶，乳液和生物系统等复杂的流体引起了极大的身体兴趣，因为它们可以作为新的功能材料应用于各种行业。复杂流体的特性可以归因于它们的较大自由度，例如分子构象和关联。分子取向是重要阶，它在创建液晶相中起着重要作用。该研究的目的是开发一种新的实验系统，用于观察液态材料的定向分子动力学。我们成功地开发了具有连续波激光器的光学KERR效应光谱技术。该分子的各向异性形状必然伴随着元素介电性。极化激光束的电场诱导分子方向，该分子取向以光学椭圆法作为KERR效应来测量。观察到近距性相位过渡温度附近的线索原子的临界现象。改进了系统以观察分子旋转的动态过程。 Pockels电池是用宽带供电驱动的，用于激光极化的高频控制。精确测量了复杂的响应函数，这为我们提供了有关液晶的相变和分子动力学的重要信息。我们在各种液晶中首次观察到光学KERR效应的松弛。激光诱导的分子取向技术将是研究液晶相变机理的强大工具。