In the realm of smartphone design, the days of protruding rear cameras may be numbered, thanks to the promising strides made in metasurface technology. Spearheaded by a collaborative team led by Professor Junsuk Rho of POSTECH, along with researchers from Korea University, a remarkable breakthrough has been achieved – the development of a water-soluble mold that could revolutionize camera lens fabrication.
Intriguingly, this cutting-edge approach addresses several critical challenges in lens production. Conventionally, methods such as electron beam lithography are not only expensive but also painstakingly slow. In sharp contrast, the team’s innovation harnesses nanoimprint lithography, a swifter and more cost-effective technique, propelled by the utilization of a mold that can dissolve in water.
The significance of this breakthrough becomes evident when considering the intricacies of separating fragile structures from molds. The larger the structure, the greater the potential for damage, hampering the attainment of the pristine high-resolution and high aspect ratio necessary for metasurfaces.
Enter the water-soluble nanoimprint mold, a game-changing solution that sidesteps the separation challenge altogether. Rather than physically extricating the structure from the mold, the researchers opted for a dissolution technique using polyvinyl alcohol (PVA), a flexible material known to dissolve effortlessly in water.
The practical application of this ingenious mold has yielded impressive results. The researchers successfully manufactured a metalens with a remarkable 1 cm area, boasting an impressive high aspect ratio of 10:1. This metalens boasts the capability to transcribe structures smaller than 100 nm, all while maintaining its effectiveness within the visible light spectrum.
Professor Junsuk Rho, the driving force behind this breakthrough, articulated the significance of the research. He underscored the achievement of combining high-resolution and high aspect ratio through nanoimprinting, made possible by the employment of a water-soluble mold. Looking ahead, he expressed optimism about the potential for large-area mold fabrication based on deep ultraviolet lithography, envisioning a future marked by affordable and rapid production of metasurfaces.