Plasmonic Focal Plane Arrays for High-Performance Terahertz Imaging

Terahertz time-domain spectroscopy (THz-TDS) and imaging systems offer unique functionalities for material characterization, non-destructive quality control (QC), chemical detection, and biomedical imaging. However, practical utilization of these systems for solving real-world problems has been limited because of the absence of high-performance, multi-pixel terahertz detectors that can offer both high data quality and fast data acquisition over a broad frequency range. Existing THz-TDS systems consist of single pixel detectors and require two-dimensional scanning of either the scanned object or the detector, which is not practical for many potential applications of these systems. Developing a broadband terahertz focal plane array (THz-FPA) can address this problem; however, realization of a THz-FPA for THz-TDS systems has not been possible yet due to the design restrictions of conventional photoconductive terahertz detectors. The plasmonic nanoantenna technology developed by the co-founders of Lookin, Inc. provides a unique solution for developing THz-FPAs. As proved by feasibility tests during the Phase I program, terahertz detectors based on plasmonic nanoantennas offer record-high sensitivity levels and, through their scalable architecture, they can be fabricated over large areas without introducing bandwidth-limiting parasitics. Encouraged by the results of the Phase I program, during which a 64-pixel THz-FPA prototype was successfully developed, Lookin, Inc. intends to further extend this advanced terahertz detector technology during the Phase II Base program to develop THz-FPAs consisting of 256×256 pixels. The THz-FPAs will be designed to offer large field-of-view (FOV) and image acquisition rates up to 10 Hz. In addition to the THz-FPA development, Lookin, Inc. plans to build a multi-pixel terahertz imaging platform through a custom-made compact, fiber-coupled, and high-power femtosecond laser. The team also plans to design various terahertz lenses to offer different functionalities, such as adjustable FOV and line scanning with the THz-FPA and multi-pixel imaging system. After the development of the proposed large-pixel-count THz-FPAs and high-speed terahertz imaging systems, Lookin, Inc. plans to use the multi-pixel terahertz imaging systems as a transformative solution for a currently unmet need in lithium-ion battery (LIB) manufacturing, in-line QC of LIB electrodes. In-line QC of LIB electrodes can improve manufacturing capability to deliver high power batteries with better shelf life, increased safety, lower cost, and decreased production lead-time. During the Phase II Option program, Lookin, Inc. plans to modify the high-speed terahertz imaging systems to be installed in LIB manufacturing facilities for high throughput scanning of LIB electrodes and conduct extensive validation studies in collaboration with battery manufacturers.