Multiplexed anti-counterfeiting meta-image displays with single-sized nanostructures

Metasurfaces have recently been used for multi-channel image displays with pixel-size lower than a wavelength, which indicates the potential application in ultra-compact anti-counterfeiting with high-dense and hidden information. However, current multi-channel metasurfaces, which can be applied in anti-counterfeiting, are based on the sophisticated nanostructure design or at the cost of giving up some controls on the optical transmission matrix to encode multiple information channels. That is, the overall degrees of freedom offered by these metasurfaces are a “zero-sum game”. Here, inspired by the orientation degeneracy indicated in Malus law, we propose a multiplexed anti-counterfeiting metasurface consisting of single-sized nanostructures, which provides a new degree of freedom to increase the information capacity of anti-counterfeiting without burdening the nanostructure design and fabrication. Specifically, the proposed metasurfaces can record a continuous grayscale image (channel one) multiplexed wit...