Spatiotemporally Encoded Plasmonic Structural Coloration for Multilevel Information Encryption and Anticounterfeiting

Metasurface-based dynamic structural colors have found wide applications in dynamic display, information encryption, and optical anticounterfeiting. However, achieving spatiotemporally encoded structural colors, essential for enhancing information capacity, remains a pivotal challenge in this field. In this study, we experimentally demonstrate a spatiotemporally encoded dynamic coloration platform based on pixelated moisture-sensitive Fabry-Pérot (FP) resonators. By locally tailoring the porosity and thickness of the top gold layer in each FP resonator, their moisture-driven response times are precisely tuned from 2 s to several minutes. This localized self-regulation effect of water molecule diffusion kinetics provides a new pathway for realizing spatiotemporally encoded plasmonic structural coloration and multilevel information encryption without the need for a complex external addressing system. As proof of concept, we demonstrate several innovative applications in information security, including bifunctional devices for sensing and information encryption, humidity-time dual-lock encryption, and time-cascaded quick response (QR) codes. Importantly, unlike conventional encryption systems, our platform maintains unprecedented stability and adaptability across a wide range of ambient conditions (30-90% RH, 20-70 °C) and diverse observation conditions (0-70° viewing angle, 0-90° polarization angle). These results indicate the system's great potential for high-security, high-capacity, and high-adaptability information security applications based on active meta-optics.