Professor Junsuk Rho and his team at POSTECH conducted a thorough quantitative analysis to determine the ideal printing material for crafting ultraviolet metasurfaces. Their research, featured in the journal Microsystems & Nanoengineering, aimed to improve the efficiency of metasurfaces in controlling light down to nanometer thickness, expanding their applications to infrared and ultraviolet light. Nanoimprint lithography, a technology used in metasurface production, promises affordable and large-scale manufacturing but suffers from low refractive index resin.
The team focused on exploring nanocomposites, integrating nanoparticles into the resin to boost its refractive index, and conducted experiments to evaluate the impact of nanoparticle concentration and solvent selection on pattern transfer and UV metaholograms. By manipulating the concentration of zirconium dioxide (ZrO2) ranging from 20% to 90%, they found that the highest pattern transfer efficiency was achieved at an 80% concentration level. When combining ZrO2 with various solvents such as methylisobutyl ketone, methyl ethyl ketone, and acetone, they achieved impressive conversion efficiencies in the ultraviolet spectrum.
Their research marks a significant milestone in establishing an optimal metric for achieving metaholograms specifically tailored for the ultraviolet domain, pioneering the development of new nanocomposites. Professor Junsuk Rho mentioned the potential use of titanium dioxide (TiO2) and silicon (Si) nanocomposites for visible and infrared light, and expressed expectations for future research focusing on refining the preparation conditions for optimal nanocomposites to advance optical metasurface fabrication technology.
The research was supported by various programs and projects from the National Research Foundation of Korea, the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, and POSCO Holdings, highlighting the collaborative effort and resources involved in advancing optical metasurface fabrication technology. The findings of this study have implications for the commercial viability and scalability of metasurfaces, offering potential for applications in next-generation displays, imaging, and biosensing, with the possibility of expanding into visible and infrared light as well.
Overall, Professor Junsuk Rho and his team have made significant progress in optimizing printing materials for ultraviolet metasurfaces, demonstrating the importance of nanocomposites in enhancing metasurface efficiency and performance. Their research opens up new possibilities for metasurface applications across different light spectra, contributing to the advancement of optical technology and fabrication methods. The collaboration and support from various organizations and funding sources have been instrumental in driving this research forward and laying the foundation for future advancements in the field.