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

Area of Science:

• Materials Science
• Optics
• Nanotechnology

Background:

• Materials with spectral selectivity in the thermal infrared are crucial for applications like thermophotovoltaics, radiative cooling, and infrared stealth.
• Existing infrared stealth technologies often rely on low-emissivity materials, which can be further improved through spectral engineering.

Purpose of the Study:

• To design and demonstrate a spectrally selective thermal emitter for efficient infrared stealth.
• To achieve simultaneous suppression of emissivity and temperature for enhanced thermal signature reduction.

Main Methods:

• Utilized the intrinsic spectral properties of aluminum nitride combined with a fully dielectric multilayered band-pass filter for spectral engineering.
• Fabricated a selective thermal emitter capable of operating from ambient temperature to 400 °C.
• Integrated the dielectric selective thermal emitter with a microwave absorber to achieve infrared and radar-compatible stealth.

Main Results:

• The emitter exhibits high emissivity (ε = 0.78) in the 5-8 μm non-atmospheric window for heat dissipation and low emissivity (ε = 0.29 in 3-5 μm, ε = 0.26 in 8-14 μm) in atmospheric windows.
• Achieved a significant temperature reduction of 8.2 °C by enhancing heat dissipation.
• Demonstrated superior infrared stealth performance compared to conventional low-emissivity materials.

Conclusions:

• The developed spectrally selective thermal emitter effectively reduces thermal signatures for infrared stealth applications.
• The fully dielectric structure offers a flexible and straightforward solution for engineering selective emission characteristics.
• The integration with microwave absorbers provides a pathway towards compatible infrared and radar stealth solutions.