NER: Torque Spectroscopy for Nanosystem Characterization and Fabrication

该项目是对NSF 01-157类纳米科学与工程倡议的响应。这项研究的目的是开发向纳米系统提供受监管的扭矩的技术；这种扭矩将在皮牛顿-纳米量级。具有角动量的Helicallv结构光将被用于光学捕获装置中，以向被捕获的粒子传递角动量，从而向被捕获的物体施加扭矩。利用螺旋波前和平面波的干涉构成的俘获波束，可以获得被困物体的位置和方向。这项研究的重点是利用传统的单光束陷阱结构，构建所需的螺旋结构激光模式作为拉盖尔-高斯(LG)光束模式，并构建LG光束模式与平面波光束模式之间的干涉图样。将进行生物分子的扭矩光谱实验。候选分子包括肌球蛋白等卷曲卷曲蛋白、纤维连接蛋白和Tenascin等模块化基质蛋白以及DNA双螺旋。这项研究计划将对知识、教育、工业和技术的进步产生广泛影响。光学扭矩捕获器是纳米科学和工程技术全面发展的一种使能技术，在纳米技术从表征到制造方面具有广泛的应用前景。在纳米规模的生物系统中，它将被用来提供对单分子行为的理解。对于纳米级结构，它将使表征依赖于旋转运动的新型纳米级结构和现象成为可能。最后，对于纳米级的制造过程，它将使新的纳米制造过程成为可能，这些过程将依赖于六维粒子的操纵，其他应用包括测量旋转纳米电机的扭矩和功率输出，测量分子的弯曲强度，测量纳米排列的阻力，以及通过光子组件驱动纳米系统。该计划还将对研究生的新课程产生影响，将纳米科学和工程学的工程和物理元素结合起来；纳米系统和纳米生物系统的研究；通过参与研究项目为本科生提供纳米技术培训机会；以及产业合作为教师、研究助理和学生提供技术转移和培训机会。

This project was received in response to Nanoscale Science and Engineering initiative, NSF 01-157, category NER. The purpose of this research is to develop the technology to deliver regulated torques to nanosystems; such torques would be on the order of piconewton-nanometers. Helicallv structured light possessing angular momentum will be used in an optical trapping arrangement to deliver angular momentum to trapped particles thereby applying a torque to the trapped object. Position and orientation of a trapped object will be achieved with a trapping beam constructed from the interference of a helical wave front and a plane wave. This research focuses on developing an optical trap using a conventional single-beam trap architecture; constructing the requisite helically-structured laser beam modes as Laguerre-Gaussian (LG) beam modes and constructing an interference pattern between LG beam modes and plane-wave beam modes. Torque spectroscopy experiments of biomolecules will be performed. Candidate molecules are coiled-coil proteins like myosin, modular matrix proteins like fibronectin and tenascin, and the DNA double helix.This research program will have a broad impact in the advancement of knowledge, education, industry and technology. An optical torque-trap is an enabling technology for the comprehensive development of nanoscience and engineering, and will have wide application in nanotechnology from characterization to fabrication. In nanoscale biosystems it would be used to provide an understanding of the behavior of single molecules. For nanoscale structures, it would enable the characterization of novel nanoscale structures and phenomena which depend upon rotary motion . Finally for nanoscale manufacturing processes it would enable new nanofabrication processes which would depend upon the manipulation of particles in six-dimensions Other applications include measuring the torque and power output of rotary nanomotors, measuring the bending strength of molecules, measuring the drag on nanobearings, and driving nanosystems by photonic components. This program will also have impacts in new curriculum for graduate students, combining elements of engineering and physics for nanoscience and engineering; the study of nanosystems and nanobiosystems; training opportunities for undergraduate students in nanotechnology through participation in research projects; and industrial collaboration providing technology transfer and training opportunities for faculty, research associates, and students.