Intellectual Merit: The objective of the proposed research is establishing and demonstrating a one-of-a-kind Terahertz imaging and sensing infrastructure at the University of Alabama that is suitable for sustaining a permanent multidimensional interdisciplinary research activity. Intellectual merit: Terahertz biomedical imaging promises to become the technique of the future for early cancer detection by combining the strengths of current imaging techniques, which could lead to much fewer false positives, while being harmless to healthy tissues. THz radiation will be generated at room temperature using a femtosecond laser source through optical down-conversion in a nonlinear optical crystal. To enhance the efficiency of THz generation, the interaction length between the THz and the optical pulses needs to be increased. This will be done using quasi-phase matching structures, such as orientation-patterned GaAs or GaN. This infrastructure will be used to gather original imaging data and thereby enable the collaborative development of complementary multi-modal imaging techniques that can yield biochemical information.
Broader Impact: The proposed outreach program is designed to attract women to pursue career engineering because it is a major health issue in their lives that transcends any ethnic and social background. Furthermore, the numerous proposed proactive education and outreach activities in the classroom and outside the University are purposefully designed to enhance the participation of all members of underrepresented groups, especially women and African American, by taking advantage of the unique position of the University of Alabama in this domain, leveraging resources already available here, and fully integrating the established research laboratory and capability into an education program in which the PI will be a role model for other members of underrepresented groups. These activities will be in addition to disseminating research data in prominent journals and widely attended scientific forums where UA students can serve as an example for others.
Intellectual merit: The proposed research activity is aimed at establishing and demonstrating a one-of-a-kind THz imaging and sensing infrastructure and know-how at the University of Alabama (UA) that is suitable for sustaining a permanent multidimensional interdisciplinary research activity in this area. Terahertz radiation, corresponding to frequencies between 0.3~10THz, is non-ionizing and has sub-mm wavelengths, which thus has a high potential not only in high-resolution medical imaging but also in yielding biologically meaningful information. Indeed, in addition to common absorption methods, THz radiation can excite interactions between adjacent molecules, resulting in the generation of secondary radiation that provides specific biochemical information of great use in imaging structures, such as tumors. We have built a Terahertz time domain spectrometer (THz-TDS) successfully through this award. This infrastructure has been actively being used to gather original imaging data, train undergraduate and graduate students, and develop complementary multi-modal imaging techniques that can yield biochemical information, and to serve as a teaching tool. The imaging system has been greatly improved and enhanced their capabilities through the versatile imaging acquisition algorithms and signal processing capabilities. We have successfully demonstrated imaging of various materials including the tissues. THz-TDS has been also used for carrier lifetime measurements in conventional semiconductors including nanowires. Our results proved THz-TDS as a non-destructive testing and characterization methods determining optical and electrical properties such as complex refractive indices, dielectric constants, and conductivity. We applied this measurement technique and calculation to various tissues including osseous tissues. This leads to study structural changes in the osseous tissues by probing the changes in optical parameters in THz frequencies, and bring new Even though THz TDS is the most versatile and applicable to many areas of research, there are still strong needs for high power and high sensitive THz sources and detectors. We proposed optical down conversion and THz generation through quasi-phase matched orientation patterned GaN using conventional Ti:S femtosecond laser. Through this project, we successfully demonstrated orientation patterned GaN and THz generation. Our method of THz generation is pending for US patent. Further work is needed to improve the performances. At the same time, we had a great progress in metamaterials based detector design operating in THz frequencies. Broader impacts resulting from the proposed activity: The proposed investigation of THz biomedical imaging techniques and modalities will help boost cancer cure and survival rates by allowing the effective early detection of cancerous tumors. The development of such imaging technology would also benefit Homeland Security applications (e.g. concealed weapon detection) since THz radiation has the unique ability to safely penetrate a wide variety of non-conducting materials (e.g. clothing). By its intrinsic nature, the topic of THz based biomedical imaging applied to early breast cancer detection has a potential to attract women to pursue a career in engineering in this field since they would be able to see the public benefit of their field of studies and because it is a major health issue in their lives that transcends any ethnic and social background. The numerous proposed proactive education and outreach activities in the classroom, outside the classroom at UA, and outside the University were performed to enhance the participation of all members of underrepresented groups, especially women and African American, by taking advantage of the University of Alabama’s unique position in this domain, leveraging resources already available here, and fully integrating the established research capability into an education program in which the PI was a role model for other members of underrepresented groups. Furthermore, this award helped one marine veteran to finish his PhD through graduate research diversity supplement. Mr. Wilbert was marine veteran, who served 4 years in Iraq and came back to continue his education. The supplement awards was one of the major force him to finish his PhD. He is graduating this May. PI gave a numerous talks at the Society of Women Engineers meetings on campus and disseminated research data through publications in refereed journals and conference proceedings, and numerous presentation and invited talks. As summarizing 1 book chapters, 9 refereed journal articles, 18 refereed conference proceedings has been published, and gave 16 invited talks, and 17 presentation in the international conferences related to this work and supports from this award. Through this award, 2 Masters (1 African American), 1 PhD (Veteran) were granted and 10 Undergraduates (including, 4 underrepresentives, with and without REU support) have been supported.
