Dozens of high resolution holograms fit on ultra thin light controlling surface
by Riko Seibo
Tokyo, Japan (SPX) May 28, 2025

From televisions and smartphones to banking cards, modern life relies heavily on technologies that manipulate light. While holography has long been a key player in this space, its traditional forms have struggled to display multiple high resolution images on a single platform. Now, researchers at POSTECH, led by Professor Junsuk Rho, have unveiled a metasurface technology capable of presenting up to 36 images on a structure finer than a human hair.

The innovation lies in a nanoscale material called a metasurface, composed of meticulously arranged silicon nitride pillars, or meta-atoms, which manipulate light at unprecedented precision. Silicon nitride's strength and optical clarity make it ideal for this application.

Each image appears based on a unique combination of light wavelength and polarization spin. For example, one setting might show a red apple under left-circularly polarized light, while switching to right-circularly polarized red light reveals a car. The metasurface encodes 36 images at 20 nm spacing within the visible spectrum and an additional 8 images spanning visible to near-infrared ranges.

This method not only simplifies the manufacturing process but also improves image clarity. By applying a noise reduction algorithm, the team eliminated much of the background interference and overlap between different images.

"This is the first demonstration of multiplexing spin and wavelength information through a single phase-optimization process while achieving low noise and high image fidelity," said Professor Rho. "Given its scalability and commercial viability, this technology holds strong potential for a wide range of optical applications, including high-capacity optical data storage, secure encryption systems, and multi-image display technologies."

Funding support came from POSCO Holdings' N.EX.T Impact Program and Korea's National Research Foundation under the Ministry of Science and ICT.

Research Report:36-Channel Spin and Wavelength Co-Multiplexed Metasurface Holography by Phase-Gradient Inverse Design

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