Double Modulation Enhances Hologram Security

A holographic color print developed by scientists in Singapore could help ensure the authenticity of identity cards and money.

AsianScientist (Jan. 21, 2019) – Researchers from the Singapore University of Technology and Design (SUTD) have invented a type of anti-counterfeiting device that can be used to secure important documents such as identity cards, passports and banknotes. They published their findings in the journal Nature Communications.

Anti-counterfeiting products are important and essential for protecting products and documents. To date, the most popular anti-counterfeiting products are based on holograms that are attached to electronic device package boxes, medicine bottles and the surfaces of bank cards. However, these anti-counterfeiting hologram products only modulate the phase of light and can be easily copied.

Scientists have now developed a more secure type of anti-counterfeiting device, a holographic color print that modulates both the phase and amplitude of light. Their device tunes the amplitude of light while projecting up to three different holograms under red, green or blue laser illumination.

The unique properties of their holographic color print were enabled by nanostructured pixels strategically arranged on a plane. Associate Professor Joel Yang of SUTD who led the study shared that the pixel arrangement was determined by a proprietary computer algorithm that takes multiple images as its input, then generates an output file with the precise pixel arrangement pattern, which is then 3D printed at the nanoscale using polymers.

“For the first time, multiple holograms that are color selective are ‘woven’ into a colorful image using advanced nanofabrication techniques. We are hopeful that these new holographic color prints are user friendly but counterfeiter unfriendly—they are readily verified but challenging to copy, and can provide enhanced security in anti-counterfeiting applications,” said Yang.

The article can be found at: Lim et al. (2019) Holographic Colour Prints for Enhanced Optical Security by Combined Phase and Amplitude Control.


Source: Singapore University of Technology and Design.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Asian Scientist Magazine is an award-winning science and technology magazine that highlights R&D news stories from Asia to a global audience. The magazine is published by Singapore-headquartered Wildtype Media Group.

Related Stories from Asian Scientist