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Diatom Cribellum-Inspired Hierarchical Metamaterials The cribellum layer of diatom skeleton, termed frustule, features a hierarchical porous structure on the nanoscale. In article number 2403304 by Xin Zhang and co-workers, diatom cribellum inspired hierarchical metamaterials are presented to integrate the perfect absorption and subwavelength color printing. These diatom cribellum-inspired metamaterials offer a fresh perspective on multifunctional metamaterial design, promising scalability production by utilizing the frustule as a template for nanopatterning or bio-template synthesis. 

Abstract Diatom exoskeletons, known as frustules, exhibit a unique multilayer structure that has attracted considerable attention across interdisciplinary research fields as a source of biomorphic inspiration. These frustules possess a hierarchical porous structure, ranging from millimeter‐scale foramen pores to nanometer‐scale cribellum pores. In this study, this natural template for nanopattern design is leveraged to showcase metamaterials that integrates perfect absorption and subwavelength color printing. The cribellum‐inspired hierarchical nanopatterns, organized in a hexagonal unit cell with a periodicity of 300 nm, are realized through a single‐step electron beam lithography process. By employing numerical models, it is uncovered that an additional induced collective dipole mode is the key mechanism responsible for achieving outstanding performance in absorption, reaching up to 99%. Analysis of the hierarchical organization reveals that variations in nanoparticle diameter and inter‐unit‐cell distance lead to shifts and broadening of the resonance peaks. It is also demonstrated that the hierarchical nanopatterns are capable of color reproduction with high uniformity and fidelity, serving as hexagonal pixels for high‐resolution color printing. These cribellum‐inspired metamaterials offer a novel approach to multifunctional metamaterial design, presenting aesthetic potential applications in the development of robotics and wearable electronic devices, such as smart skin or surface coatings integrated with energy harvesting functionalities.