CAREER: Integrated Research and Education in Nano- and Microscale Photoacoustic and Photothermal Microscopy

CMS 0448796CAREER：纳米和微米级光声和光热显微镜的综合研究和教育T.W.默里：波士顿大学摘要本CAREER项目的主要目标是实现微米和纳米尺度上的热性能和机械性能的快速、准确成像，从而有助于提高微米尺度系统的性能和可靠性，并有助于理解和控制纳米尺度材料的热性能和机械性能。PI开发了新颖的光声和光热（PA/PT）测量功能，用于纳米级表面特性和亚表面缺陷的非接触和非破坏性成像，沿着了解测量量与目标材料的热机械特性的关系。一种用于生产PA/PT成像的高度局部化的热源和探针的技术进行了探索，其目标是将PA/PT显微镜的横向分辨率推向纳米级范围。这种新的成像模式利用了在等离子体共振频率下激发的纳米颗粒周围的高吸收和局部场增强，并将在寻求理解和表征纳米级材料行为方面产生广泛的影响。其次，研制了一种高分辨率的光声显微系统，该系统使用高频（GHz）调制激发源。预期通过带宽减小和脉冲编码技术，可以改善脉冲系统的信噪比，从而扩大这种无损检测技术适用的应用范围。本提案的最后一个重点领域是对复杂材料系统中声波和热波的激光生成进行建模，这是解释这些系统中的热和声信号以及准确反演这些信号以获得材料特性信息所必不可少的领域。研究结果将直接应用于纳米制造：在线监测制造过程以及测量“制造”材料系统的基本特性。该项目支持研究生和本科生的研究人员，并培训这些学生在工程科学的广泛的横截面，该项目借鉴包括无损检测，应用光学，弹性波传播和纳米工程。这个职业生涯项目支持新科学家学习经验（LENS）计划的开发和实施，在该计划中，学术上有风险的7年级和8年级学生来到波士顿大学进行为期一周的动手演示和解决问题的活动。该计划针对处于科学技能发展关键时期的学生，旨在减少缺乏基本科学和数学能力的高中毕业生人数。为LENS计划开发的多媒体演示文稿被放在网上，以传播给其他教育工作者，并通过波士顿大学的学习资源网络（LERNet）计划提供给其他外展计划。PI已经安排了一名研究生在劳伦斯利弗莫尔国家实验室工作一个夏天。这个机会使学生能够与LLNL的几位激光超声专家进行互动，并扩大他/她的教育背景。PI在材料的力学行为领域开发了一门新的本科课程，其中将讨论材料的NDE。PI还为固体力学实验技术的研究生课程开发NDE演示。PI担任专业社会学生团体的教师顾问，并将在BU主办未来的区域学生会议。PI计划邀请当地公司和教育机构的代表向学生讲述NDE的重要性。

CMS 0448796CAREER: Integrated Research and Education in Nano- and Microscale Photoacoustic and Photothermal MicroscopyT.W. Murray: Boston UniversityAbstract The primary objective of this CAREER project is to enable rapid, accurate imaging of thermal and mechanical properties on micrometer and nanometer length scales, thereby contributing to the effort to improve the performance and reliability of micron scale systems and in the effort to understand and control the thermal and mechanical behavior of materials at the nanoscale. The PI develops novel photoacoustic and photothermal (PA/PT) measurement capabilities for the noncontact and nondestructive imaging of surface properties and subsurface defects at the nanoscale, along with an understanding of how the measured quantities relate to the thermo-mechanical properties of the target material. A technique for producing highly localized heat sources and probes for PA/PT imaging is explored, with the goal of pushing the lateral resolution of PA/PT microscopy to the nanoscale regime. This novel imaging modality makes use of the high absorption and local field enhancement around nanoparticles excited at the plasmon resonance frequency, and will have a broad impact in the quest to understand and characterize material behavior at the nanoscale. Next, A high-resolution photoacoustic microscopy system is developed which uses a high-frequency (GHz) modulated excitation source. Improvements in signal to noise ratio over pulsed systems are expected through bandwidth reduction and pulse coding techniques, expanding the range of applications for which this NDE technique is suitable. The final thrust area in this proposal focuses on the modeling of laser generation of acoustic and thermal waves in complex materials systems, an area which is essential for the interpretation of thermal and acoustic signals in these systems, and for accurate inversion of these signals to obtain material property information. The research results will have direct applications in nanofabrication: for online monitoring of the fabrication process as well as in the measurement of the fundamental properties of "as-fabricated" materials systems. This project supports both graduate and undergraduate researchers, and trains these students in a wide cross-section of engineering science that this project draws upon including NDE, applied optics, elastic wave propagation, and nanoscale engineering. This CAREER project supports the development and implementation of the Learning Experiences for New Scientists (LENS) program in which academically at-risk 7th and 8th grade students come to Boston University for a week of hands on demonstrations and problem solving activities. This program targets students at a critical time in the development of science skills, and is aimed at reducing the number of students graduating from high school who lack basic proficiency in science and math. The multi-media presentations developed for the LENS program are placed on the Web to disseminate to other educators, and are made available for other outreach programs through the Learning Resource Network (LERNet) program at Boston University. The PI has arranged for a graduate student to work at Lawrence Livermore National Lab for one summer under this project. This opportunity allows the student to interact with several experts on laser ultrasonics at LLNL, and to broaden his/her educational background. The PI develops a new undergraduate course in the area of mechanical behavior of materials, in which the NDE of materials will be discussed. The PI also develops NDE demonstrations for a graduate course in experimental techniques in solid mechanics. The PI serves as the faculty advisor for a professional society student group, and will host a future regional student conference at BU. The PI plans to invite representatives from local companies and educational institutions to speak to the students about the importance of NDE.