Polarization Dependent Nonlinear Optical Properties of Biomolecules

普渡大学的加思·辛普森得到了实验物理化学计划的支持，以开发一个系统的框架，为解释定向生物分子组装的偏振相关非线性光学(NLO)测量提供基础。主要目标是：(1)改进和测试基于微扰理论的描述生物聚合物偏振相关非线性光学性质的计算方法，(2)发展新的仪器方法，用于二次谐波产生(SHG)、和频产生(SFG)和双光子吸收的详细偏振分析，以及(3)评估微扰理论方法的有效性，通过对模型取向的细菌视紫红质薄膜和胶原纤维的电子倍频、和频和电子双光子吸收的联合测量。非线性光学方法在理解生物系统的微观结构方面有很大的应用前景。该项目将使能够有效地用于化学和生物的新技术得到重大发展。随着免费分发软件包NLOPredict的继续开发，以及发起和组织新的非线性光学夏季年度会议，这项工作的有益影响将扩大到更广泛的社区。

Garth Simpson of Purdue University is supported by the Experimental Physical Chemistry Program to develop a systematic framework that will provide a foundation for interpreting polarization-dependent nonlinear optical (NLO) measurements of oriented biomolecular assemblies. The primary objectives are to: (1) refine and test computational methods based on perturbation theory for describing the polarization-dependent NLO properties of biopolymers, (2) develop new instrumental methods for detailed polarization analysis in second harmonic generation (SHG), sum frequency generation (SFG), and two-photon absorption, and (3) assess the range of validity of the perturbation theory approach from combined electronic SHG, vibrational SFG, and electronic two-photon absorption measurements of model oriented bacteriorhodopsin thin films and collagen fibrils. Nonlinear optical methods have great promise as probes to understand microscopic structure in biological systems. This project will enable significant development of new techniques that can be used effectively in chemistry and biology. The useful impacts of this work will be extended to the broader community with the continued development of the freely distributed software package NLOPredict, and initiation and organization of a new annual summer meeting on nonlinear optics.