CAREER: Integrated Research and Education in Nano- and Microscale Photoacoustic and Photothermal Microscopy
|Anticipated Total Funding||$400,000.00|
|Anticipated End Year||2010|
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.