Second Harmonic Ellipsometry and Spectroscopy of Biological Interfaces

在这个由化学系实验物理化学计划资助的项目中，普渡大学的Garth Simpson教授将利用基于表面二次谐波（SHG）产生和频率产生（SFG）的非线性光学技术研究表面上生物分子的手性。 SHG偏振测量比传统的基于吸收的方法对界面手性更敏感几个数量级。 本研究的目标是获得生物界面的非线性光学性质的基本理解，从而建立一个解释未来的研究这样的系统的基础。 本项目的研究内容包括三个方面：1）阐明有序手性薄膜非线性光学测量中大手性效应的机理; 2）发展非线性光学零椭圆偏振法，作为一种新的、可靠的方法，用于获得和解释定向手性和非手性表面系统的非线性偏振测量;以及3）对模型脂质和蛋白脂质界面进行非线性光学测量，以提供解释更复杂生物系统的非线性光学测量的背景。 研究生和本科生以及博士后研究人员将参与这项研究。除了这些基础研究之外，Simpson教授还将通过普渡大学科学约束试点计划开发适用于K-12教育的激光仪器模块。 该方案通过三个组成部分针对印第安纳波利斯公立学校的7至12年级学生：1）课后方案; 2）后续活动; 3）导师教师专业发展。

In this project, funded by the Experimental Physical Chemistry Program of the Chemistry Division, Prof. Garth Simpson of Purdue Universty will investigate the chirality of biological molecules on surfaces using nonlinear optical techniques based on surface second harmonic (SHG) generation and sum frequency generation (SFG). SHG polarization measurements are by several orders of magnitude more sensitive to interfacial chirality than traditional absorbance-based methods. The goal of this research is to gain a fundamental understanding of the nonlinear optical properties of biological interfaces and thereby establish a foundation for interpreting future studies of such systems. The research component of this project consists of three specific tasks: 1) to elucidate the mechanisms responsible for the large chiral effects in nonlinear optical measurements of ordered chiral films; 2) to develop nonlinear optical null ellipsometry as a novel and robust approach for acquiring and interpreting nonlinear polarization measurements of oriented chiral and achiral surface systems; and 3) to make nonlinear optical measurements of model lipid and proteolipid interfaces to provide a context in which to interpret nonlinear optical measurements of more complex biological systems. Graduate and undergraduate students as well as postdoctoral research associates will participate in the research.In addition to these fundamental investigations Prof. Simpson will develop laser instrumentation modules suitable for use in K-12 Education through the Purdue University Science Bound pilot program. This program targets 7th through 12th grade students in the Indianapolis Public Schools by means of three components: 1) after school programs; 2) follow-up activities; and 3) mentor teacher professional development.