Combined multi-band infrared camouflage and thermal management via a simple multilayer structure design

Infrared camouflage is crucial for high-temperature objects to avoid detection, and spontaneous infrared radiation is also an important way for high-temperature objects to dissipate heat. Therefore, selective infrared emission has become significant for the coating design of surfaces such as aircraft, which require low emission in the atmospheric window band (3-5 µm and 8-14 µm) and high emission outside it (5-8 µm). This Letter employs a simple multilayer film structure to achieve selective regulation of the material emission spectrum. Combining the transfer matrix method and genetic algorithm, a multilayer film structure containing 12 layers of three high-temperature-resistant materials (SiO₂, TiO₂ and Ge) has been designed. It shows fairly low emissivity in two main bands of infrared detection (ε_3∼5µm=0.14, ε_8∼14µm=0.21) and high emissivity outside them (ε_5∼8µm=0.86), and this infrared selectivity can be well maintained with the incident angle rising from 0 to 60 deg. The Poynting vector distribution in the material at different incident wavelengths is analyzed to further explore the interference mechanism to achieve spectral selective emission. The significance of this work lies in the construction of a relatively simple coating design while ensuring efficient infrared camouflage and thermal management performance.