Advanced Terahertz Imaging Systems based on Plasmonic Antenna Arrays

太赫兹波对于医学成像应用非常有吸引力，因为它们不会对人体组织构成电离危险，因为与医学成像系统中经常使用的较短波长的波相比，太赫兹波的能量非常低。此外，与光波相比，太赫兹波对生物组织的散射较少，因为它们的波长较长，因此可以更深入地了解不同类型的生物组织。此外，水的几条吸收线位于太赫兹频谱中，这使得太赫兹波成为区分具有不同水合水平的组织的非常强大的手段，这通常对诊断目的有用。太赫兹波的这些吸引人的属性的结合已经引起了人们对太赫兹成像系统的极大兴趣，并已被用于各种医学成像和诊断应用。尽管近年来太赫兹成像系统有了显著的进步，但现有的太赫兹成像系统在尺寸、图像采集时间、图像分辨率和可探测深度方面存在限制，这限制了它们在各种医学成像和诊断应用中的潜在使用范围。该计划的研究部分将通过开发一种在活体成像和诊断应用中具有潜在应用的高性能脉冲太赫兹成像系统来解决现有太赫兹成像系统的一些物理限制。此外，该计划将通过开发新课程、招募和参与本科生以及组织高中研讨会，将研究与教育和外展活动相结合。这项研究的目标是开发新一代非接触式太赫兹成像系统，与现有的太赫兹成像技术相比，这种系统提供更大的可探测深度和更快的图像采集速度。为此，将实现一种新型的脉冲太赫兹成像系统，该系统基于与商用内窥镜兼容的大面积等离子体光导太赫兹源和探测器的二维阵列。大面积等离子体光电导源和探测器的使用将提高太赫兹源的输出功率、太赫兹探测器的探测灵敏度和信噪比，从而使成像系统的可探测深度大大增加。这项拟议的工作为太赫兹技术在各种医疗诊断应用中的潜在应用提供了一个新的视角，由于现有太赫兹成像系统的浅可探测深度和笨重性质，目前这些应用是不可能的。拟议的理论研究将提供对等离子体太赫兹源/探测器操作的基本物理限制的详细了解，而实验工作将开发与内窥镜系统兼容的适当设备制造和封装工艺。

Terahertz waves are very attractive for medical imaging applications since they do not pose an ionization hazard for human tissue, due to their very low energy compared to shorter wavelength waves often used in medical imaging systems. Moreover, terahertz waves experience less scattering from biological tissue compared to optical waves due to their longer wavelengths making it possible to see deeper into different biological tissue types. Additionally, several absorption lines of water lie in the terahertz frequency spectrum, making terahertz waves very powerful means for distinguishing between tissues with different hydration levels that is often useful for diagnostics purposes. The combination of these attractive attributes of terahertz waves has created a great deal of interest in terahertz imaging systems and has been utilized for various medical imaging and diagnostics applications. In spite of a significant advancement in terahertz imaging systems over recent years, existing terahertz imaging systems have constraints in their size, image acquisition time, image resolution, and detectable depth, which has limited the scope of their potential use for various medical imaging and diagnostics applications. The research component of this program will address some of the physical limitations of existing terahertz imaging systems by developing a high-performance pulsed terahertz imaging system with potential application in in-vivo imaging and diagnostics applications. Additionally, this program will integrate research with education and outreach activities by developing new courses, recruitment and involvement of undergraduate students, and organizing high-school seminars. The objective of this research is to develop a new generation of non-contact terahertz imaging systems that offer significantly larger detectable depths and faster image acquisition rates compared to existing terahertz imaging technologies. For this purpose, a novel pulsed terahertz imaging system based on a two-dimensional array of large area plasmonic photoconductive terahertz sources and detectors compatible with a commercial endoscope will be implemented and experimentally demonstrated. The use of large area plasmonic photoconductive sources and detectors will enhance the output power of terahertz sources, detection sensitivity of terahertz detectors, and signal-to-noise ratio, thus enabling significantly larger detectable depths for the imaging system. The proposed work presents a new perspective on the potential use of terahertz technology for various medical diagnostics applications that are not currently possible due to the shallow detectable depth and bulky nature of existing terahertz imaging systems. The proposed theoretical investigation will provide a detailed understanding of the fundamental physical limitations of plasmonic terahertz source/detector operations, while the experimental effort will develop appropriate device fabrication and packaging processes compatible with endoscopy systems.