Development of scalable anti-counterfeiting optical metasurfaces with nanoprint

Due to the fusion of our life with IoT (Internet of Things) technologies, we are about to enter the hyper-connected communities. Here at, identity concerned about who I am, who they are, what things are has become surely essential issues. However, the emergence of information society entails a lot of problems concerned with data and information security. For enhancement of the security levels, a new concept of cryptography in a variety of fields has been of great interests of international society.

Metasurfaces, the 2D counterparts of metamaterials, are known to be capable of manipulating amplitude and wavefront of incident light. This unprecedented function has enabled structural coloring, holograms, polarization encoding and so on. Researchers have noticed that metasurfaces have remarkable potential as an optical security device owing to its ultra-high resolution (100,000dpi), multiple data storage possibilities, and near-permanent life-time.

In this project, we plan to develop multi-functional metasurfaces working as not only structural color prints under white light and but also fully polarized holograms under coherent laser source with combination of output polarizer/retarder. Those features can possibly be the ultimate optical security technologies.

The project targets the initiation of a productive long-term research collaboration between Germany, Korea, and Japan (note: the Japanese group will participate through the funding of the Korean project partner). In previous years, both groups from Korea and Germany had already some interaction and Prof. Rho visited Paderborn University already two times. By the establishment of a detailed research collaboration, this previous contact will be strengthened and even further extended into a multinational collaboration network. The work of the groups is strongly complementary: the German team has extensive experience in the design of novel holographic metasurface elements while the Korean team has an international reputation in the realization of challenging nanostructures for optical meta-devices. Here, the Japanese team can further contribute to the project by providing new 3D fabrication schemes for metamaterials that will greatly enhance the capabilities for the project.

Both teams (Korea and Germany) will work on a cooperation agreement between both institutions in the field of material science which should result in future exchange of graduate students for research as well as academic studies. For that Paderborn University has already established two international Master programs (Materials Science, Optoelectronics & Photonics).