Security applications of metasurface holograms with color print features

Optical security devices (OSDs) leverage the properties of multicolor holograms to display different images depending on the type of illumination, with applications in data encryption and document authentication, helping to combat counterfeiting. Recent advances in nanofabrication have demonstrated new possibilities for enhancing OSD design, including those combining color printing with holography.

Despite interest in these integrated metasurface holograms, design complexity and scalability issues hinder their realistic applications. To fill research gaps, Khaleghi et al. proposed a novel hybrid dielectric/plasmonic metasurface approach that balances color printing and holography tradeoffs.

The authors proposed a hybrid metasurface hologram device encoded with color print images and studied it via simulations. One part of the device consists of a three-layer color filter for blue, green, and red channels, and the other part of the device consists of nanopillars modulating the phase of outgoing light. The authors thus achieved low cross-talk between color channels.

“Crosstalk is a critical issue affecting the performance of dual-function metasurface holograms,” said author Kenneth Crozier. “By achieving a crosstalk between filter channels of less than 17%, better than previous reports, the proposed hybrid dielectric/plasmonic metasurface design demonstrates an important advancement in improving the purity and quality of multicolor holographic images integrated with color print features.”

The authors expect that hybrid metasurfaces will improve the security features of confidential documents.

“We believe this paper will motivate policy-makers, optical engineers, and researchers in optical security documents, such as banknotes and passports, to pursue dual-functionality designs instead of traditional single-function devices,” said Crozier. “Developing a low-cost fabrication process for practical implementations would be a fruitful next step.”

Source: “High resolution multicolor holograms encoded into color print images with hybrid dielectric/plasmonic metasurfaces,” by Seyed Saleh Mousavi Khaleghi, Dandan Wen, Jasper Cadusch, and Kenneth B. Crozier, Applied Physics Letters (2025). The article can be accessed at https://doi.org/10.1063/5.0232468 .