Photonic Crystal Heterostructure Film for High-Temperature Mid-Far Infrared Stealth and Radiative Cooling with Band-Selective Radar Transmission

Photonic crystal films possess excellent capability for infrared radiation modulation, and applying them to the surfaces of high-temperature targets represents an effective approach to achieving mid-far infrared stealth. In this work, a novel photonic crystal heterostructure film comprising 12 layers and constructed from Al2O3, Ge, and HfO2 is designed based on the transfer matrix method. Experimental measurements show that, at room temperature, the film exhibits an emissivity of 0.181 in the mid-infrared band and 0.144 in the far-infrared band, demonstrating favorable infrared stealth performance; meanwhile, an emissivity of 0.475 in the non-detection band (5–8 µm) enables effective radiative cooling. As the temperature is gradually elevated up to 500 °C, the film structure maintains favorable infrared stealth and radiative cooling performance. Furthermore, both theoretical simulations and experimental measurements demonstrate that the film exhibits excellent wave-transmission performance in the 2–18 GHz range, which enables its potential integration with radar-absorbing materials to achieve multi-band compatible stealth. The designed and fabricated photonic crystal heterostructure film provides a new reference for infrared stealth strategies under high-temperature conditions.