PECASE: Electromagnetic Scattering and Propagation in Random Media at Terahertz Frequencies

ecs - 0545417 l。太赫兹（THz）成像正在成为一项有前途的新技术，随着超快光学激光器产生太赫兹脉冲的进步，科学界对这一潜力的探索终于成为可能。该研究计划的目标是通过开发先进的电磁（EM）模型来表征宽带太赫兹（THz）脉冲在随机介质中的传播和散射，这些模型集成到严格的系统仿真框架中。这些模型还将被用作电磁学教育的互动学习工具，并为本科生融入研究过程提供途径。研究工作的成功完成将导致对太赫兹传播特性的理解取得重大进展，特别侧重于太赫兹光谱在爆炸物探测和医学成像中的应用。计算模型也将促进基于计算机的可视化工具的发展，这些工具将把研究纳入课堂和实验室环境中。整个过程将以全面的指导方针记录下来，并根据对学生学习和发展的影响进行定量评估。这些报告将通过在互联网上发布和在美国工程教育学会（American Society for Engineering Education）等教育期刊上发表，传播给更广泛的教育界。提出的研究包括开发用于从随机介质预测太赫兹场统计的计算软件，并将该计算纳入系统表征，包括量子力学（QM）框架和太赫兹脉冲产生的频谱。因此，这项活动需要：1)发展基于粒子和连续变化的随机介质模型，以表示炸药和生物医学材料的不均匀性；2)扩展电磁散射理论，以解释发生在太赫兹波长的粒子共振和色散；3)应用傅立叶合成，将QM、EM和系统光谱成分结合起来，产生时域响应。4)通过与华盛顿大学（UW）太赫兹测量设施的合作实验活动验证所得模型；5)将模型纳入教育活动。知识价值。所提议的活动具有实质性的智力价值。它将极大地促进对太赫兹波传播的理解，同时为随机介质模型和EM散射计算技术提供严格的评估。该代码将由PI在波特兰州立大学（PSU）装备齐全的西北电磁学和声学研究实验室（NEAR-Lab）开发，并将利用PI先前的研究活动，其中PI开发了随机介质模型和微波通过密集球体系统传播的散射公式。该方法的一个独特组成部分是合成时域响应的过程，以获得严格推导的端到端集成系统响应，该响应捕获了复杂的散射物理，并提供了探索和评估太赫兹成像对各种材料的潜在应用的能力。更广泛的影响。拟议的活动将促进科学理解，同时通过开发可视化工具和将本科生纳入（和评估）研究过程的附带程序丰富教育环境。它将通过共享实验设施来促进PSU和UW之间的伙伴关系，并通过（女性）PI的领导为女性在工程领域提供榜样，从而加强女性在这两个机构中的参与。潜在的社会效益确实令人印象深刻，包括检测有害爆炸装置或检测癌症存在的能力。科学成果将通过科学期刊和技术会议广泛传播。

ECS-0545417L. Zurk Portland State UniversityTerahertz (THz) imaging is emerging as a promising new technology, and exploration of this potential by the scientific community has finally become possible with advances in ultrafast optical lasers to generate THz pulses. The goal of this research program is to characterize broadband Terahertz (THz) pulse propagation and scattering in random media with the development of advanced electromagnetic (EM) models that are integrated into a rigorous systems simulation framework.These models will additionally be utilized as an interactive learning tool for electromagnetics education and to provide an avenue for integration of undergraduates into the research process. Successful completion of the research e_ort will result in significant advances in understanding of THz propagation characteristics, with specific focus on application of THz spectroscopy to detection of explosives and to medical imaging. The computational models will also facilitate the development of computer-based visualization tools that will incorporate research into lecture and laboratory environments. The process will be documented with comprehensive guidelines and evaluated quantitatively in terms of the impact on student learning and development. These will be disseminated to the wider educational community by posting to the internet and presentation in educational journals such as the American Society for Engineering Education.The proposed research consists of the development of computational software for the prediction of THz field statistics from random media, and the incorporation of this calculation into a system characterization which includes the quantum mechanical (QM) framework and the spectrum of the THz pulse generation. The activity thus requires: 1) development of particle-based and continuously varying random medium models to represent the inhomogeneities of the explosive and biomedical materials, 2) extension of EM scattering theory to account for particle resonances and dispersion that occur at THz wavelengths, 3) application of Fourier synthesis to combine the QM, EM, and system spectral components to generate the time domain response, 4) validation of the resulting models through a collaborative experimental activity with the University of Washingtons(UW) THz measurement facility, and 5) incorporation of the models into educational activities.Intellectual Merit. The proposed activity has substantial intellectual merit. It will significantly advance understanding of THz wave propagation, while simultaneously providing a rigorous assessment of random media models and techniques for EM scattering calculation. The code will be developed in the PIs well-equipped Northwest Electromagnetics and Acoustics Research Laboratory (NEAR-Lab) at Portland State University (PSU), and will leverage previous research activities in which the PI developed random medium models and scattering formulations for microwave propagation through densely packed systems of spheres. A unique component of the proposed approach is the process for synthesizing the time domain response to obtain a rigorously derived end-to-end integrated system response that captures the complicated scattering physics and provides the ability to explore and assess the potential application of THz imaging for a variety of materials.Broader Impacts. The proposed activity will advance scientific understanding while simultaneously enriching the educational environment through development of visualization tools and an accompanying procedure for the incorporation (and evaluation) of undergraduate students into the research process. It will promote partnership between PSU and UW through shared use of experimental facilities, and strengthen the participation of women in each of these institutions by providing a role model for women in engineering through the leadership of the (woman) PI. The potential societal benefits are truly impressive, including the ability to detect harmful explosive devices or detect the presence of cancer. The scientific results will be broadly disseminated through scientific journals and technical conferences.