Terahertz (THz) sensing is emerging as a promising new technology with application to a wide number of compelling problems in material probing, medical imaging, and device design. This tremendous potential has prompted rapid advancements in THz sensor technology, but advanced processing approaches that exploit the unique capability of THz sensors are still not fully developed. Perhaps the most promising application, three-dimensional (3D) THz imaging with simultaneous chemical characterization, has remained elusive due to challenges posed by the unique geometries of THz imaging configurations and the subsequent scattering of THz waves. A core contribution of this research will be the development of advanced physics-based signal processing techniques for 3D imaging with concurrent spectroscopic material characterization. These techniques are based on predictions of electromagnetic scattering theory (for example, reflection from planar cracks and curved layers) to preferentially combine reflection measurements from multiple sensors, frequencies and polarizations. This work will produce methods for advanced 3D focusing of Synthetic Aperture Imaging systems with the simultaneous detection of spectroscopic material features from THz reflection spectra. While this work will provide advances in specific THz sensing applications, the need to understand and exploit wave interactions with physics-based processing has wide applicability, and the integrated theoretical, modeling and measurement effort proposed will significantly advance knowledge in the field.
Broader Impacts This research will support an integrated activity of research and education at Portland State University in collaboration with international academic and industry partners. The potential societal benefits are truly impressive, potentially enabling the ability for rapid and robust 3D chemical mapping for future industry applications in non-destructive evaluation, medical imaging, and security screening. This research will specifically target two imaging applications: 1) rapid assessment of the shape and material composition of coated pharmaceutical tablets; and 2) detection of cracks in solar panels for enhanced production of ?green? energy. In addition to these broader impacts of the work, undergraduate and graduate students will have the opportunity to engage in cutting-edge THz research and participate in the international collaboration. The PI will continue her activities of K-12 outreach and mentoring of women in science and engineering.
