"Fake Currency and Counterfeits Beware"…Development of Next-Generation Anti-Counterfeiting and Tampering Display

[Asia Economy Reporter Kim Bong-su] Domestic researchers have developed a device that appears identical to ordinary printed materials but reveals hidden information when viewed with an infrared camera. It is highly regarded as a next-generation anti-counterfeiting security technology because it can contain various information in one place.

The research team led by Professor Song Young-min of the Department of Electrical, Electronics and Computer Engineering at Gwangju Institute of Science and Technology (GIST) succeeded in developing a next-generation multi-spectral anti-counterfeiting display for security that embeds infrared information invisible to the naked eye into images rendered in various colors.

This display can reproduce vivid colors in the visible light wavelength range, appearing as ordinary color printing to the naked eye, but when observed with a thermal imaging camera that detects the infrared spectrum, hidden information can be confirmed. Unlike existing security elements based on holography or fluorescent materials, it is indistinguishable from regular printing. Since it does not reveal itself as a security device, it can contain multiple pieces of information, granting it a high security rating.

Previously, multi-spectral photonics technology faced difficulties in development because optical properties had to be independently controlled by wavelength. However, the research team applied different optical resonance structures. By individually controlling the visible and infrared bands, they succeeded in implementing two spectra within a single structure. The visible light region uses an ultra-thin color structure composed of metal-high absorption materials capable of coloration at the scale of tens of nanometers. The infrared region selectively achieves strong absorption through a plasmonic structure utilizing micro-hole patterns, realizing multi-spectral characteristics at an ultra-thin thickness (~3 μm).

To implement visible color reproduction and infrared information embedding, the team overcame the previous limitation of fabrication only on very restricted substrates and achieved it on ultra-thin flexible device substrates. Since no separate energy is required for operation, it can be applied in various fields requiring security such as finance, government offices, and the military.

Professor Song said, "The technology to prevent counterfeiting has been further enhanced by inducing multi-spectral light control," adding, "In the future, by applying materials capable of active modulation, it is expected to be developed into a next-generation ultra-compact security display that can change images in real time."

This research result was published as the cover paper on June 4 in the international journal Advanced Optical Materials (IF: 9.926).

This content was produced with the assistance of AI translation services.