Tunable mid-infrared broadband absorption in the atmospheric window of wavelength in 3–5 μm using VO2 phase transition in a three-layer metamaterial

Tunable metasurfaces have garnered considerable attention for their remarkable ability to manipulate electromagnetic waves within carefully designed nanostructures. Achieving resonant absorption requires precise control over the geometry and size of micro-nano structures. This study introduces a highly versatile metasurface platform that leverages the unique phase transition properties of vanadium dioxide (VO2) for controlled absorption. Our design features a planar layered structure with a 0.1 μm thick VO2 top layer, enabling tunability in both thermal and intensity aspects. We demonstrate significant tuning of broadband light absorption across the mid-infrared spectrum, with absorption rates ranging from approximately 30 %–98 % in the critical atmospheric infrared window of 3–5 μm. This range is crucial for infrared sensing, imaging, and communication applications. Notably, the absorption rate increases as the temperature decreases, indicating a positive shift in dynamics, for which we provide a physical explanation. Numerical simulations highlight the ability to control absorption bandwidth by adjusting the thickness and temperature of VO2 layer. These adaptable broadband absorbers hold significant promise for a diverse range of applications, including absorption filters, thermal emitters, thermos photovoltaics, and thermal imaging. Furthermore, the introduced thermally switchable, spectrally selective metamaterials can find applications in dynamic infrared camouflage and active radiative thermal management, opening new horizons in the realm of metamaterial-based technologies.