Thinner lenses, brighter colors: Metalens research clears two hurdles for AR and VR glasses
AR and VR glasses once seen only in science fiction may soon be realized not as bulky stacks of lenses but as a single eyeglass-like optical element. That future is now closer to reality.
Thin, advanced lenses known as metalenses are paving the way for lighter, more compact AR and VR glasses, according to recent research from Pohang University of Science and Technology (POSTECH). Metalenses, which are ultrathin and made of densely packed nanoscale structures, have the potential to replace bulky stacks of conventional lenses.
However, two key challenges must be overcome for metalenses to become commercially viable in these devices: achieving high optical performance and developing scalable manufacturing methods.
The POSTECH team addressed these challenges by developing new techniques for fabricating metalenses. In the first study, they used two-photon lithography, a high-precision 3D printing method, to directly create complex three-dimensional nanopillars. By varying the height of these nanopillars, the team was able to precisely focus red, green, and blue light onto the same point, resulting in sharp full-color images when integrated with an OLED display.
This achievement, detailed in a Nature Communications article, demonstrated that relatively inexpensive, low-refractive-index materials could be used to create achromatic metalenses that focus all visible colors at once.
In the second study, the researchers focused on scalable manufacturing. They employed a grayscale electron-beam lithography technique to create a height-encoded nano-template, which was then used in nanoimprint lithography for replicating the metalenses. This new approach allowed for the production of multi-height structures simultaneously, improving both the optical performance and scalability of the fabrication process.
By overcoming the limitations of low-refractive-index materials, the team has created two critical components for the industrialization of metalens-based optics: high optical performance and scalable replication strategies. Lead researcher Junsuk Rho emphasized the significance of these findings, stating that they could enable the development of full-color achromatic metalenses for AR and VR displays in practical industrial use, with potential applications extending to various optical industries.
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