Adaptive thermal camouflage using sub-wavelength phase-change metasurfaces

Date
2022-12-09
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Source Title
Journal of Physics D: Applied Physics
Print ISSN
0022-3727
Electronic ISSN
1361-6463
Publisher
Institute of Physics Publishing Ltd.
Volume
56
Issue
2
Pages
1 - 8
Language
English
Type
Article
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Abstract

Sub-wavelength metasurface designs can be used to artificially engineer the spectral thermal signature of an object. The real-time control of this emission can provide the opportunity to switch between radiative cooling (RC) and thermal camouflage functionalities. This performance could be achieved by using phase-change materials (PCMs). This paper presents a sub-wavelength dynamic metasurface design with the adaptive property. The proposed metasurface is made of vanadium dioxide (VO2) nanogratings on a silver (Ag) substrate. The design geometries are optimized in a way that both narrowband and broadband mid-infrared (MIR) emitters can be realized. At low temperatures, insulating VO2 nanogratings trigger the excitation of Fabry–Perot mode inside the grating and surface plasmon polaritons at the metal–dielectric interface with an emission peak located in the MIR region to maximize the RC performance of the design. As temperature rises, the PCM transforms into a metallic phase material and supports excitation of Wood's anomaly and localized surface plasmon resonance modes. Accordingly, the thermal signature is adaptively suppressed.

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Keywords
Thermal camouflage, Metasurface, Phase-change materials, Surface plasmon polaritons, Wood’s anomaly resonance
Citation
Published Version (Please cite this version)