Brownian Transport Through Modulated Potential Energy Landscapes

通过调制势能景观的布朗输运

• 批准号: 0451589
• 负责人: David Grier
• 金额: --
• 依托单位: New York University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-09 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0451589&HistoricalAwards=false
• 关键词: Brownian; Transport; Through; Modulated; Potential

This program focuses on how colloidal particles move through extensive potential energy landscapes created with dynamic holographic optical tweezers. Transport through modulated potential energy landscapes is a classic problem in condensed matter physics, with variants arising in systems as diverse as flux flow through type-II superconductors, quasiparticle tunneling in Josephson junctions and procession in biological molecular motors. While much is known about transport in one-dimensional periodic potentials, much more remains to be understood regarding modulated Brownian transport in higher dimensions, particularly in aperiodic, quasiperiodic, random, and time-varying landscapes, all of which figure heavily in natural and industrial settings. Previous efforts to understand such processes have been hampered by the difficulty of controlling most relevant systems' potential energy landscapes while tracking their microscopic components' motions. Dynamic holographic optical tweezers present a unique opportunity to construct arbitrary one-, two-, and three-dimensional potential energy landscapes for micrometer-scale colloidal particles by projecting up to several thousand optical traps in any desired configuration. Unlike most other model systems, colloidal particles' microscopic motions can be tracked with exquisite accuracy using digital video microscopy. The combination of optical manipulation and high-resolution particle tracking provides an extraordinarily flexible and well-characterized model system for studying driven modulated Brownian transport, not only for single particles but also for strongly interacting systems of particles. In addition to the fundamental knowledge gained from such studies, the particular application to mesoscopic transport promises immediate practical applications in nanotechnology, biotechnology, and photonics.How does an electron find its way through the labyrinth of a metallic glass? How does a DNA molecule thread through a gel? Answering such questions requires a new fundamental insights into how objects traverse complicated potential energy landscapes. And the answers will have immediate practical ramifications for fields as diverse as high-temperature superconductivity, drug discovery, nanotechnology and engineering. This program combines state-of-the-art micromanipulation made possible by the recent introduction of holographic optical tweezers (HOTs) with precision digital video microscopy to provide just such insights. The heart of this program is provided by HOT's ability to create arbitrary custom-designed potential energy landscapes from an ordinary beam of laser light. The technique uses computer-generated holograms to craft the beam into thousands of individual optical traps, each of which can be moved independently in three dimensions under computer control. If a single optical trap can be likened to Star Trek's tractor beam, then holographic optical tweezers more closely resemble the holodeck. Micrometer-scale colloidal particles driven through such latticeworks of light trace out solutions to long-standing fundamental physics questions. In so doing, they also provide the basis for practical applications such as sorting proteins, DNA, nanoclusters, and living cells using light. The new techniques on which this program is based were developed with direct involvement of high school and undergraduate students, as well as graduate students and postdocs. These students' unique training in these methods has helped them to land positions in top-rated schools, as well as long-term employment in industry and academia. This program's methods have been patented, and the patents have led to the foundation of a new industry in optical micromanipulation. Such substantive involvement of industry and students at all levels will continue to be a central theme of this program.

该程序的重​​点是胶体颗粒如何通过动态全息光学镊子产生的广泛势能景观进行移动。 通过调制势能景观的运输是凝聚态物理物理学的一个经典问题，在流经II型超导体的系统中会产生变体，Josephson连接中的Quasiparticle隧道和生物分子运动中的游动。 尽管对一维周期电位的运输知之甚少，但对于更高维度的调制布朗运输，尤其是在基质，准层状，随机和时变的景观中，还有更多的了解，这些景观在自然和工业环境中都很大。 以前的理解此类过程的努力受到控制最相关的系统势能景观的困难，同时跟踪其微观组件的动作。 动态全息光学镊子提供了一个独特的机会，可以通过在任何所需构型中投影多达几千个光学陷阱来构建微米尺度胶体颗粒的任意单，二维和三维势能景观。 与大多数其他模型系统不同，可以使用数字视频显微镜以精确的精度跟踪胶体颗粒的微观运动。 光学操纵和高分辨率粒子跟踪的组合提供了一种非常灵活且特征良好的模型系统，用于研究驱动的调制布朗运输，这不仅用于单个颗粒，而且用于强烈的粒子相互作用系统。 除了从此类研究中获得的基本知识外，对介质运输的特殊应用也有望在纳米技术，生物技术和光子学上立即实用应用。 DNA分子如何通过凝胶螺纹？ 回答此类问题需要对物体如何穿越复杂的势能景观的新基本见解。 答案将对像高温超导性，药物发现，纳米技术和工程等多样化的领域产生立即的实践影响。 该程序结合了最先进的微观计算，这是由于最近引入全息光学镊子（HOTS）和精确的数字视频显微镜，以提供此类见解。 该程序的核心是HOT能够从普通的激光光束创建任意定制设计的势能景观的能力。 该技术使用计算机生成的全息图将光束制作成数千个单独的光学陷阱，每个陷阱都可以在计算机控制下以三个维度独立移动。 如果可以将单个光学陷阱比作《星际迷航》的拖拉机光束，则全息光学镊子更类似于Holodeck。 千分尺尺度的胶体颗粒通过此类光线的晶格驱动，从而将解决方案带到了长期存在的基本物理问题上。 这样一来，它们还为使用光的蛋白质，DNA，纳米群和活细胞等实用应用提供了基础。 该计划所基于的新技术是通过直接参与高中和本科生以及研究生和博士学位的直接参与的。 这些学生在这些方法中的独特培训帮助他们在最高的学校以及行业和学术界的长期就业中占据了职位。 该计划的方法已获得专利，专利为光学微观计算的新行业提供了基础。 各级行业和学生的实质性参与将继续是该计划的核心主题。