Visible Light and Infrared Camouflage Based on Epsilon Near Zero Materials

As advanced detection technologies advance toward intelligent capabilities, the camouflage has become increasingly prominent. In recent years, research has focused on integrating infrared directional thermal emission and selective full-angle thermal emission in the long-wave infrared spectrum with visible light camouflage through structural innovations, including multilayer photonic crystals, phase-change materials, equidistantly excited gratings, and 2D materials. To date, the integration of infrared directional thermal emission with visible light camouflage remains unexplored in published literature. This study proposes a novel approach for achieving infrared directional thermal emission by employing gradient epsilon-near-zero (ENZ) materials. Thin film structures, including Al₂O₃/TiO₂/Ge/SiO₂/SiO and TiO₂/Ta₂O₅/Ge/Y₂O₃/MgO, are designed to facilitate directional thermal radiation emission in the 8–12 and 12–16 µm bands, respectively. These structures enable the selective detection of p-polarized infrared signals at specific angles, thereby advancing infrared camouflage strategies. Furthermore, leveraging the thin-film interference effect of visible light, a color modulation layer is incorporated into the gradient ENZ structure. By manipulating the thickness of the ZnS film layer, extensive color variations can be achieved, thereby providing a foundation for visible light camouflage applications.