NER: Development of an Ultrafast Scanning Probe Microscope

本纳米级探索性研究（NER）提案是响应NSE，NSF 02-148而收到的。 这项为期一年的项目涉及开发一种新型的飞秒无孔径扫描近场光学显微镜（FANSOM），它将提供前所未有的纳米空间分辨率和飞秒时间分辨率相结合的运动图像。该仪器将用于探测电子激发，退相，和人口衰减动力学的个别人工纳米结构，如量子点，以及光诱导的电子和构象动力学的个别有机大分子。该显微镜将基于一个成熟的无孔近场成像技术，其中光散射从一个尖锐的金属尖端扫描整个基板提供纳米空间分辨率的图像。使用飞秒激光脉冲的光学泵浦探测技术将获得快速的时间分辨率。对应于泵浦和探测脉冲之间的延迟时间增加的多个图像将被组装为具有飞秒时间分辨率的纳米尺度动力学过程的实际电影。 该项目的成功完成将产生一个强大的新工具来探测地球，在几乎所有领域（物理，化学，材料科学，生命科学，量子计算等）都有潜在的应用。其中有趣的动力学发生在纳米级，并被不均匀的影响所掩盖。所获得的运动图像的图形性质，再加上纳米结构的动力学的基本和实际的兴趣，使该仪器成为科学学生和公众的理想教育工具。 研究生和本科生将参与仪器的开发，以及其使用的科学研究。 该项目由材料研究和物理部门共同支持。该纳米尺度探索性研究（NER）提案是响应NSE，NSF 02-148而收到的。 这个为期一年的项目涉及开发一种新型显微镜，它将提供具有近原子空间分辨率和超快时间分辨率的前所未有的组合的移动图像。特别是，该仪器将用于探测单个人造纳米结构的激发和衰变，以及单个有机大分子的光诱导变化。该显微镜将基于一种成熟的技术，其中从一个尖锐的金属尖端扫描整个表面的光散射提供纳米空间分辨率的图像。利用超短激光脉冲将获得快速的时间分辨率。一系列泵浦脉冲激发纳米结构，并且时间延迟的探测脉冲用于成像。对应于泵浦脉冲和探测脉冲之间的增加的时间延迟的多个图像然后将被组装为感兴趣的过程的实际电影。 该项目的成功完成将产生一个强大的新工具来探测地球，在几乎所有领域（物理，化学，材料科学，生命科学等）都有潜在的应用。有趣的过程发生在纳米尺度上。所获得的运动图像的图形性质，再加上对纳米结构的基本和实际兴趣，使该仪器成为科学学生和公众的理想教育工具。 研究生和本科生将参与仪器的开发，以及其使用的科学研究。 该项目由材料研究和物理部门共同支持。

This Nanoscale Exploratory Research (NER) proposal was received in response to NSE, NSF 02-148. The one-year project involves developing a novel femtosecond apertureless scanning near-field optical microscope (FANSOM), which will provide moving images with the unprecedented combination of nanometer spatial resolution and femtosecond time resolution. The instrument will be used to probe the electronic excitation, dephasing, and population decay dynamics of individual artificial nanostructures such as quantum dots, as well as the photoinduced electronic and conformational dynamics of individual organic macromolecules. The microscope will be based on a proven apertureless near-field imaging technique, in which light scattering from a sharp metallic tip scanned across the substrate provides images with nanometer spatial resolution. Fast temporal resolution will be obtained using optical pump-probe techniques with femtosecond laser pulses. Multiple images corresponding to increasing delay time between pump and probe pulses will then be assembled as actual movies of nanometer-scale dynamical processes with femtosecond time resolution. Successful completion of this project will give rise to a powerful new tool to probe the nanoworld, with potential applications in virtually every field (physics, chemistry, materials science, life sciences, quantum computing, etc.) in which interesting dynamics occurs at the nanoscale and is obscured by inhomogeneous effects. The graphical nature of the moving images obtained, coupled with the fundamental and practical interest in the dynamics of nanostructures, make this instrument an ideal educational tool for both scientific students and the general public. Graduate and undergraduate students will be involved with the development of the instrument, as well as its use scientific studies. The project is jointly supported by the Divisions of Materials Research and Physics.This Nanoscale Exploratory Research (NER) proposal was received in response to NSE, NSF 02-148. The one-year project involves developing a novel microscope that will provide moving images with the unprecedented combination of near-atomic spatial resolution and ultrafast time resolution. In particular, the instrument will be used to probe the excitation and decay of individual artificial nanostructures, as well as light-induced changes of individual organic macromolecules. The microscope will be based on a proven technique, in which light scattering from a sharp metallic tip scanned across a surface provides images with nanometer spatial resolution. Fast time resolution will be obtained with ultrashort laser pulses. A series of pump pulses excites the nanostructure, and time-delayed probe pulses are used for imaging. Multiple images corresponding to increasing time delay between pump and probe pulses will then be assembled as actual movies of the processes of interest. Successful completion of this project will give rise to a powerful new tool to probe the nanoworld, with potential applications in virtually every field (physics, chemistry, materials science, life sciences, etc.) in which interesting processes occur at the nanoscale. The graphical nature of the moving images obtained, coupled with the fundamental and practical interest in nanostructures, make this instrument an ideal educational tool for both scientific students and the general public. Graduate and undergraduate students will be involved with the development of the instrument, as well as its use scientific studies. The project is jointly supported by the Divisions of Materials Research and Physics.