Quasi-3-D Au mushrooms with programmable morphology for high-capacity flexible plasmonic encoding

Plasmonic encoding composed of metallic nanostructures makes a great contribution to the practical application of information encryption. However, most reports have so far shown the preparation of single or binary plasmonic encoding patterns because of the technical difficulty of assembling multiplex nanostructures on a single platform, which cannot satisfy the requirements of high encoding capacity for increasing information security. Herein, we developed a strategy based on plasma etching combined with in-situ growth to fabricate patterned arrays of quasi-three-dimensional (3-D) plasmonic Au nano-mushrooms with controlled morphologies, and successfully realized ideal high-capacity plasmonic encoding by arranging Au nano-mushrooms on one platform. On this basis, such multiplex encoding patterns have been transferred to the flexible substrate to realize the triple-mode encryption of the Morse code of “FUNSOM”, indicating great prospects in the applications of information encryption and data storage.