Dynamic selective emitter for low infrared signal over wide temperature range based on VO2

Abstract

The infrared signal intensity of objects contains the thermal radiation from objects themselves and the reflected signal from their surface. Here, we theoretically propose the rule of regulating the infrared signal intensity in mid-wave infrared band, which is influenced by both the reflected solar irradiation and the self-emitted radiation. Then we propose a dynamic selective emitter (DSE) operating in the mid-infrared (MIR) band based on vanadium dioxide (VO2) for lowest infrared signal intensity within the low and high temperature ranges. In the dielectric state of VO2, the selective emitter exhibits the broadband selective absorption attributed to the excitation of magnetic polariton resonance, which can effectively reduce the solar irradiation reflection in 3–4.5 μm band (R‾3–4.5 μm = 0.18) and suppress the thermal radiation in 4.5–5 μm and 8–14 μm band (ε‾4.5–5 μm = 0.28, ε‾8–14 μm = 0.02). In the metallic state of VO2, the resonance absorption disappears and the structure exhibits broadband low emissivity in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) bands (ε‾3–5 μm = 0.28, ε‾8–14 μm = 0.21) for suppression of the thermal radiation. This work highlights the impact of solar irradiation on MWIR camouflage and offers new possibilities for solar and infrared spectral regulation.