Spectrally Selective Thermal Emitter for Efficient Infrared Stealth Compatible with Microwave Absorption

Materials exhibiting spectral selectivity in the thermal infrared waveband have received considerable attention in thermophotovoltaic, radiative cooling, and infrared stealth areas. Herein, a thermal emitter with remarkable spectral selectivity is designed to achieve efficient infrared stealth through the simultaneous suppression of emissivity and temperature. Our method for spectral engineering relies on the intrinsic spectral characteristics of aluminum nitride and a fully dielectric multilayered band-pass filter. The proposed emitter that functions from ambient temperature to 400 °C has high-emissivity in the nonatmospheric window (ε_5–8 μm = 0.78) for heat dissipation, and low-emissivity in the atmospheric windows (ε_3–5 μm = 0.29; ε_8–14 μm = 0.26). The spectrally selective thermal emitter achieves a real temperature reduction of 8.2 °C via facilitating the heat dissipation process and exhibits superior infrared stealth capabilities through dual suppression of emissivity and thermal signature, outperforming conventional low-emissivity counterparts widely used in infrared stealth applications. Moreover, we realize infrared radar-compatible stealth by integrating a dielectric selective thermal emitter with a microwave absorber. This work provides a straightforward solution to engineering the selective emission characteristics for infrared stealth with great flexibility by a fully dielectric structure and is of great significance to promote the application of the selective emissive material in infrared stealth compatible with microwave absorption.