Adv Mater. 2021 Nov 03. e2107243
Innovative multiplexing technologies based on nano-optics for anti-counterfeiting have been proposed as overt (visible without tools) and covert (hidden and only visible with tools) technologies to secure products and make them difficult to counterfeit. However, most of these nano-optical anti-counterfeiting materials are metasurfaces and metamaterials with complex and expensive fabrication process, often resulting in materials that are not damage tolerant. Highly efficient anti-counterfeiting technologies with easy fabrication process are targeted for intuitive and effective authentication of banknotes, secure documents and goods packing. Here, a simple strategy exploiting self-assembling and nanoimprinting technique to fabricate a composite lattice photonic crystal architecture featuring full spatial control of light, multiplexed full-pixel imaging, and multichannel cryptography combined with customized algorithms is reported. In particular, the real-time encryption/recognition of mobile quick response codes and anti-counterfeiting labels on a postage stamp, encoded by our proposed photonic architecture, are both demonstrated. The wave optics of scattering, diffraction, and polarization process involved are also described, validated with numerical simulations and experiments. By introducing a new degree of freedom in the three-dimensional space, the multichannel image (multiplexed image) switching exhibits unprecedented variability of encryption, providing a promising roadmap to achieve larger information capacity, better security, and higher definition for the benefit of modern anti-counterfeiting security. This article is protected by copyright. All rights reserved.
Keywords: anti-counterfeiting; composite lattice photonic crystal; information multiplexing; polarization