Infrared stealth without overheating

Conventional infrared stealth technology, used in military applications, suppresses emissivity across the entire infrared spectrum. While this strategy avoids infrared detection, it results in poor heat dissipation and overheating.

Li et al. proposed a spectrally selective emitter that provides infrared stealth while allowing radiative cooling. The design reduces emissivity in the 3 to 5 µm and 8 to 14 µm atmospheric infrared bands, the wavelength ranges that need to be blocked for infrared stealth performance, while maintaining high emissivity in the 5 to 8 µm band — which is not relevant to infrared sensing. The unblocked emission band enables radiative cooling to reduce dependence on cooling systems.

The proposed design could enable targets to avoid detection by infrared sensors while dissipating heat via thermal radiation, “a critical technological breakthrough for stealth applications in high-heat sources, such as hypersonic vehicles and aircraft carrier decks,” said author Xiaohu Wu.

The emitter is expected to achieve selective emission through its structure, which is made up of Si/HfO₂ multilayer films and SiO₂. The multilayer films reflect light in the atmospheric bands while the SiO₂ promotes high emissivity in the non-atmospheric band. The emitter is also expected to be robust against polarization, making it adaptable for different environments.

Though the structure of the spectrally selective emitter and its efficacy have been studied computationally, the spectrally selective emitter has not yet been fabricated. This is the next step for further testing on its ease of integration into existing stealth technologies.

“We provide a complete technological roadmap — from simulation and design to performance tuning — for future researchers, and lay a solid foundation for early-stage development of military stealth platforms and civilian thermal control materials,” Wu said.

Source: “Near-perfect spectrally selective emitter for infrared stealth and radiative cooling,” by Mingze Li, Xiqiao Huang, Biyuan Wu, and Xiaohu Wu, Journal of Applied Physics (2025). The article can be accessed at https://doi.org/10.1063/5.0271012 .