Lithography-free thermal camouflage device with efficient thermal management for ultrahigh-temperature objects

Abstract

Infrared detectors make use of atmospheric transmission windows, typically in the 3–5 μm and 8–14 μm ranges, to identify objects by capturing the thermal radiation they emit, thereby posing a threat to the survival of military assets like aircraft. For high-temperature objects, minimizing emissivity in the 3–5 μm band is more important for effective infrared stealth. Additionally, radiative cooling utilizing a non-atmospheric window in the 5–8 μm range can efficiently lower the temperature of hot objects. In this study, we employ cost-effective molybdenum (Mo) in combination with germanium (Ge) dielectric to achieve selective emission in the infrared spectrum. Using the Finite Element Method (FEM), the average emissivity in the 3–5 μm band is calculated to be 0.29, while in the 5–8 μm band, the emissivity reaches 0.86. We also conduct infrared thermal imaging simulations, confirming its effectiveness for mid-infrared (MIR) stealth under both high and low-temperature conditions, as well as its radiative cooling capability. In addition, the film we propose has potential for application in high-temperature environments compared to previous studies, with a simple structure that is easy to fabricate. Its emissivity in the 5–8 μm band is significantly better than that of previous works, presenting highly promising application opportunities.