Switchable and expandable mid-infrared broadband metasurface absorber for adaptive infrared stealth based on VO2 phase change materials

Dynamic thermal emission with broadband tunability has attracted increasing interest in energy and military fields. Here, a thermally switchable and expandable metasurface absorber with broadband mid-infrared emission is proposed based on a metallic resonant element and vanadium dioxide (VO₂) phase change material film. Through the insulating-metal transition of VO₂, the metasurface switches between "stealth" and "non-stealth" states across the mid-infrared spectrum, and even active tuning of the absorption bandwidth and resonant peak can be achieved. At room temperature, the absorber shows near-perfect broadband absorption in the long-wave infrared atmospheric window. At high temperatures, the absorption band moves toward 5-8 μm while the atmospheric window bands present low emissivity, allowing infrared camouflage and effective heat dissipation. The proposed metasurface absorber has simple structural geometry and broad, switchable spectral response in the infrared region, showing promising applications in thermal photonics, including information storage, infrared stealth, thermal imaging, and detectors.