Nano-Metamaterial Design and Fabrication, Hybridized with Various Nanostructures for Gigantic THz Electromagnetic Wave Modulation and Their Biochemical Applications

Large-scaled metamaterial design and fabrication, hybridized with various nanostructures for gigantic terahertz (THz) electromagnetic wave modulation and their applications. Their potential applications as highly sensitive target molecule-specific sensors, amplifying interactions between light and materials, are particularly noteworthy [1-2]. On the one hand, the terahertz (THz) waves offer non-destructive interactions with molecular modes for the sensing purpose, and reasonable process capabilities in terms of fabrication size. Metamaterials operating at this range, with similar-sized structures (micrometer scale), can be manufactured using photolithography methods on a wafer-to-chip basis. Notably, a large-area nanoscale process was successfully developed by selectively combining different techniques based on their intended purpose. This structure takes the form of a slot-shaped antenna, with a width of hundreds of nanometers and a high aspect ratio, extending tens of micrometers in the transverse direction. To enhance sensitivity and minimize noise levels, over 1,000 antennas per sensor chip were designed and arranged in an array configuration. The design of the metamaterial was thoughtfully engineered to enable the tuning of its resonant frequency by adjusting the antenna's length. Furthermore, the additional nanostructures including nanowires, self-assembled nanoparticles, 2D materials such as MXene, graphene, and catalytic materials as well were integrated to get further functionality. This innovative feature allows excellent detection of trace amounts of biomaterials, leading to several groundbreaking research outcomes at the forefront of the field.<br/>In conclusion, we successfully produced nanoscale THz metamaterials using various process equipment, enabling high field enhancement, thus improving sensing and imaging ability. These THz metamaterial sensing chips demonstrated the ability to detect even DNA nucleotides, COVID viruses, micro-plastics, and trace biochemical substances with greatly improved sensitivity compared to existing light sources [3-4]. Its unique and powerful capabilities offer significant advancements in sensing and control applications, promising to revolutionize electro-optics and open up new possibilities across various industries.<br/><br/><b>References </b><br/>[1] Y. Roh et al., Ultrastrong coupling enhancement with squeezed mode volume in terahertz nano-slots, Nano Letters 23, 7086 (2023)<br/>[2] G. Lee et al., Frontiers in Terahertz Imaging Applications beyond Absorption Cross Section- and Diffraction-Limits, ACS Photonics 9, 1500 (2022)<br/>[3] S. Lee et al., Detection and discrimination of SARS-CoV-2 spike protein-derived peptides using THz metamaterials, Biosensors and Bioelectronics 113981 (2022)<br/>[4] E. Yu et al., Nanoscale terahertz monitoring on multi-phase dynamic assembly of nanoparticles under aqueous environment, Advanced Science 2004826 (2021)<br/><b>Acknowledgment: </b>The National Research Foundation of Korea (NRF) (2023R1A2C2003898), and KIST Institutional Program (No. 2E32451)<br/><b>Keywords</b>: Metamaterial, Terahertz spectroscopy, nanostructures