Coupling of Epsilon-Near-Zero Mode to Mushroom-Type Metamaterial for Optimizing Infrared Suppression and Radiative Cooling

Abstract

Abstract We report a complementary metal oxide semiconductor (CMOS) compatible metamaterial-based spectrally selective absorber/emitter (MBSSAE) for infrared (IR) stealth, which has the low absorption/emissivity in the IR atmospheric transmission window (3 µm–5 µm, 8 µm–14 µm) and ultra-high and broadband absorption/emissivity in the IR non-atmospheric window (5 µm–8 µm). We propose a novel method for the broadband absorption/emissivity in 5 µm–8 µm with incorporation of an epsilon-near-zero (ENZ) material between the top patterned aluminum (Al) disks layer and the silicon oxide (SiO2) spacer layer. With an appropriate design, the peaks in the IR atmospheric transmission window can be suppressed while the peak intensity in the non-atmospheric window remains high. The optimized MBSSAE has an average absorption/emissivity less than 10% in 8 µm–14 µm and less than 6% in 3 µm–5 µm. And the average absorption/emissivity in 5 µm–8 µm is approximately over 64%. This proposed scheme may introduce the opportunities for the large-area and low-cost infrared stealth coating, as well as for the radiative cooling, spectral selective thermal detector, optical sensor, and thermophotovoltaic applications.

Keywords

• Metamaterials
• infrared stealth
• ENZ mode
• Rabi splitting
• broadband thermal emitter