Revolutionary Janus Metasurface Developed for Enhanced Optical Security

**KAIST's research team** led by Professor **Jonghwa Shin** has achieved a technological breakthrough with the development of the **Janus metasurface**. This innovative metasurface allows for perfect asymmetric light transmission, overcoming longstanding limitations of traditional metasurfaces that struggled to control light's intensity, phase, and polarization directionally. The Janus design, inspired by the dual-faced Roman god, enables the metasurface to perform two independent optical functions depending on the direction of light. KAIST's solution includes an optical encryption technology that displays different holograms based on light direction and polarization, significantly enhancing security as information is only decodable under specific conditions. This technology's potential applications span **quantum communication** to **AR** and **LiDAR systems**. The lighter and thinner structure of the metasurface is expected to drive the miniaturization of optical devices. **Hyeonhee Kim** and **Joonkyo Jung** contributed as co-first authors, and their work is to be published in **Advanced Materials**.